Universe Today

The Sun is increasing its intensity on schedule, continuing its approach to solar maximum. In just over a 24-hour period on May 5 and May 6, 2024, the Sun released three X-class solar flares measuring at X1.3, X1.2, and X4.5. Solar flares can impact radio communications and electric power grids here on Earth, and they also pose a risk to spacecraft and astronauts in space.

NASA released an animation that shows the solar flares blasting off the surface of the rotating Sun, below.

NASA’s Solar Dynamics Observatory captured these images of the solar flares — as seen in the bright flashes in the upper right — on May 5 and May 6, 2024. The image shows a subset of extreme ultraviolet light that highlights the extremely hot material in flares and which is colorized in teal. Credit: NASA/SDO

Predicting when solar maximum will occur is not easy and the timing of it can only be confirmed after it happens. But NOAA’s Space Weather Prediction Center (SWPC) currently estimates that solar maximum will likely occur between May 2024 and early 2026. The Sun goes through a cycle of high and low activity approximately every 11 years, driven by the Sun’s magnetic field and indicated by the frequency and intensity of sunspots and other activity on the surface. The SWPC has been working hard to have a better handle on predicting solar cycles and activity. Find out more about that here.  

Solar flares are explosions on the Sun that release powerful bursts of energy and radiation coming from the magnetic energy associated with the sunspots. The more sunspots, the greater potential for flares.

Flares are classified based on a system similar to the Richter scale for earthquakes, which divides solar flares according to their strength. X-class is the most intense category of flares, while the smallest ones are A-class, followed by B, C, M and then X. Each letter represents a 10-fold increase in energy output. So an X is ten times an M and 100 times a C. The number that follows the letter provides more information about its strength. The higher the number, the stronger the flare.

Flares are our solar system’s largest explosive events. They are seen as bright areas on the Sun and can last from minutes to hours. We typically see a solar flare by the photons (or light) it releases, occurring in various wavelengths.

Sometimes, but not always, solar flares can be accompanied by a coronal mass ejection (CME), where giant clouds of particles from the Sun are hurled out into space.  If we’re lucky, these charged particles will provide a stunning show of auroras here on Earth while not impacting power grids or satellites.

Thankfully, missions like the Solar Dynamics Observatory, Solar Orbiter, the Parker Solar Probe are providing amazing views and new details about the Sun, helping astronomers to learn more about the dynamic ball of gas that powers our entire Solar System.

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Does another undetected planet languish in our Solar System’s distant reaches? Does it follow a distant orbit around the Sun in the murky realm of comets and other icy objects? For some researchers, the answer is “almost certainly.”

The case for Planet Nine (P9) goes back at least as far as 2016. In that year, astronomers Mike Brown and Konstantin Batygin published evidence pointing to its existence. Along with colleagues, they’ve published other work supporting P9 since then.

There’s lots of evidence for the existence of P9, but none of it has reached the threshold of definitive proof. The main evidence concerns the orbits of Extreme Trans-Neptunian Objects (ETNOs). They exhibit a peculiar clustering that indicates a massive object. P9 might be shepherding these objects along on their orbits.

This orbital diagram shows Planet Nine (lime green colour, labelled “P9”) and several extreme trans-Neptunian objects. Each background square is 100 AU across. Image Credit: By Tomruen – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=68955415

The names Brown and Batygin, both Caltech astronomers, come up often in regard to P9. Now, they’ve published another paper along with colleagues Alessandro Morbidelli and David Nesvorny, presenting more evidence supporting P9.

It’s titled “Generation of Low-Inclination, Neptune-Crossing TNOs by Planet Nine.” It’s published in The Astrophysical Journal Letters.

“The solar system’s distant reaches exhibit a wealth of anomalous dynamical structure, hinting at the presence of a yet-undetected, massive trans-Neptunian body—Planet Nine (P9),” the authors write. “Previous analyses have shown how orbital evolution induced by this object can explain the origins of a broad assortment of exotic orbits.”

To dig deeper into the issue, Batygin, Brown, Morbidelli, and Nesvorny examined Trans-Neptunian Objects (TNOs) with more conventional orbits. They carried out N-body simulations of these objects that included everything from the tug of giant planets and the Galactic Tide to passing stars.

29 objects in the Minor Planet Database have well-characterized orbits with a > 100 au, inclinations < 40°, and q (perihelia) < 30 au. Of those 29, 17 have well-quantified orbits. The researchers focused their simulations on these 17.

This figure from the research shows the 17 planets, their orbits, their perihelions, semi-major axes, and their inclinations. Image Credit: Batygin et al. 2024.

The researchers’ goal was to analyze these objects’ origins and determine if they could be used as a probe for P9. To accomplish this, they conducted two separate sets of simulations. One set with P9 in the Solar System and one set without.

The simulations began at t=300 million years, meaning 300 million years into the Solar System’s existence. At that time, “intrinsic dynamical evolution in the outer solar system is still in its infancy,” the authors explain, while enough time has passed for the Solar System’s birth cluster of stars to disperse and for the giant planets to have largely concluded their migrations. They ended up with about 2000 objects, or particles, in the simulation with perihelia greater than 30 au and semimajor axes between 100 and 5000 au. This ruled out all Neptune-crossing objects from the simulation’s starting conditions. “Importantly, this choice of initial conditions is inherently linked with the assumed orbit of P9,” they point out.

The figure below shows the evolution of some of the 2,000 objects in the simulations.

These panels show the evolution of selected particles within the calculations that attain nearly planar (i < 40°) Neptune-crossing orbits within the final 500 Myr of the integration. “Collectively, these examples indicate that P9-facilitated dynamics can naturally produce objects similar to those depicted in Figure 1” (the previous figure), the researchers explain. The top, middle, and bottom panels depict the time series of the semimajor axis, perihelion distance, and inclination, respectively. The rate of chaotic diffusion greatly increases when particles attain Neptune-crossing trajectories. Image Credit: Batygin et al. 2024.

These are interesting results, but the researchers point out that they in no way prove the existence of P9. These orbits could be generated by other things like the Galactic Tide. In their next step, they examined their perihelion distribution.

This figure from the research shows the perihelion distance for particles in a simulation with P9 (left) and without P9 (right.) The P9-free simulation shows a “rapid decline in perihelion distribution with decreasing q, as Neptune’s orbit forms a veritable dynamical barrier,” the researchers explain. Image Credit: Batygin et al. 2024.

“Accounting for observational biases, our results reveal that the orbital architecture of this group of objects aligns closely with the predictions of the P9-inclusive model,” the authors write. “In stark contrast, the P9-free scenario is statistically rejected at a ~5? confidence level.”

The authors point out that something other than P9 could be causing the orbital unruliness. The star was born in a cluster, and cluster dynamics could’ve set these objects on their unusual orbits before the cluster dispersed. A number of Earth-mass rogue planets could also be responsible, influencing the outer Solar System’s architecture for a few hundred million years before being removed somehow.

However, the authors chose their 17 TNOs for a reason. “Due to their low inclinations and perihelia, these objects experience rapid orbital chaos and have short dynamical lifetimes,” the authors write. That means that whatever is driving these objects into these orbits is ongoing and not a relic from the past.

An important result of this work is that it results in falsifiable predictions. And we may not have to wait long for the results to be tested. “Excitingly, the dynamics described here, along with all other lines of evidence for P9, will soon face a rigorous test with the operational commencement of the VRO (Vera Rubin Observatory),” the authors write.

A drone’s view of the Rubin Observatory under construction in 2023. The 8.4-meter is getting closer to completion and first light in 2025. The Observatory could provide answers to many outstanding issues, like the existence of Planet Nine. Image Credit: Rubin Observatory/NSF/AURA/A. Pizarro D

If P9 is real, what is it? It could be the core of a giant planet ejected during the Solar System’s early days. It could be a rogue planet that drifted through interstellar space until being caught up in our Solar System’s gravitational milieu. Or it could be a planet that formed on a distant orbit, and a passing star shepherded it into its eccentric orbit. If astronomers can confirm P9’s existence, the next question will be, ‘what is it?’

If you’re interested at all in how science operates, the case of P9 is very instructive. Eureka moments are few and far between in modern astronomy. Evidence mounts incrementally, accompanied by discussion and counterpoint. Objections are raised and inconsistencies pointed out, then methods are refined and thinking advances. What began as one over-arching question is broken down into smaller, more easily-answered ones.

But the big question dominates for now and likely will for a while longer: Is there a Planet Nine?

Stay tuned.

The post New Evidence for Our Solar System’s Ghost: Planet Nine appeared first on Universe Today.

It’s that time again. NIAC (NASA Innovative Advanced Concepts) has announced six concepts that will receive funding and proceed to the second phase of development. This is always an interesting look at the technologies and missions that could come to fruition in the future.

The six chosen ones will each receive $600,000 in funding to pursue the ideas for the next two years. NASA expects each team to use the two years to address both technical and budgetary hurdles for their concepts. When this second phase comes to an end, some of the concepts could advance to the third stage.

“These diverse, science fiction-like concepts represent a fantastic class of Phase II studies,” said John Nelson, NIAC program executive at NASA Headquarters in Washington. “Our NIAC fellows never cease to amaze and inspire, and this class definitely gives NASA a lot to think about in terms of what’s possible in the future.”

Here they are.

Fluidic Telescope (FLUTE): Enabling the Next Generation of Large Space Observatories

Telescopes are built around mirrors and lenses, whether they’re ground-based or space-based. The JWST’s large mirror is 6.5 meters in diameter but had to be folded up to fit inside the rocket that launched it and then unfolded in space. That’s a tricky engineering feat. Engineers are building larger and larger ground-based telescopes, too, and they’re equally tricky to design and build. Could FLUTE change this?

FLUTE envisions lenses made of fluid, and the FLUTE team’s concept describes a space telescope with a primary mirror 50 meters (164 ft.) in diameter. Creating glass lenses for a telescope this large isn’t realistic. “Using current technologies, scaling up space telescopes to apertures larger than approximately 33 feet (10 meters) in diameter does not appear economically viable,” the FLUTE website states.

But in the microgravity of space, fluids behave in an intriguing way. Surface tension holds liquids together at their surfaces. We can see this on Earth, where some insects use surface tension to glide along the surfaces of ponds and other bodies of water. Also, on Earth, surface tension holds small drops of water together. But in space, away from Earth’s dominating gravity, surface tension is much more effective. There, water maintains the most energy efficient shape there is: a sphere.

Another force governs water: adhesion. Adhesion causes liquids to cling to surfaces. In the microgravity of space, adhesion can bind liquid to a circular, ring-like frame. Then, due to surface tension, the liquid will naturally adopt a spherical shape. If the liquid can be made to bulge inward rather than outward, and if the liquid is reflective enough, it creates a telescope mirror.

The FLUTE team would like to make optical components in space. The liquid would stay in the liquid state and form an extremely smooth light-collecting surface. As a bonus, FLUTE would also self-repair after any micrometeorite strike.

The FLUTE study is led by Edward Balaban from NASA’s Ames Research Center in California’s Silicon Valley. The FLUTE team has already done some tests on the ISS and on zero-g flights.

FLUTE researchers experience microgravity aboard Zero Gravity Corporation’s G-FORCE ONE aircraft while operating an experiment payload during a series of parabolic flights. Image Credits: Zero Gravity Corporation/Steve Boxall

Pulsed Plasma Rocket (PPR): Shielded, Fast Transits for Humans to Mars

It takes too long to get to Mars. It’s a six-month journey each way, plus time spent on the surface. All that time in microgravity, exposure to radiation, and other challenges make the trip very difficult for astronauts. PPR aims to fix that.

PPR isn’t a launch vehicle for escaping Earth’s gravity well. It would be launched on a heavy lift vehicle like SLS and then sent on its way.

PPR was originally derived from the Pulsed Fission Fusion concept. But it’s more affordable, and also smaller and simpler. PPR might generate 100,000 N of thrust with a specific impulse (Isp) of 5,000 seconds. Those are good numbers. PPR could reduce the travel time to Mars to two months.

It has other benefits as well. It could propel larger spacecraft to Mars on trips longer than two months, carrying more cargo and also provide heavier shielding against cosmic rays. “The PPR enables a whole new era in space exploration,” the team writes.

PPR is basically a fusion system ignited by fission. It’s similar to a thermonuclear weapon. But rather than a run-away explosion, the combined energy is directed through a magnetic nozzle to produce thrust.

In phase two, the PPR team intends to optimize the engine design to produce more specific impulse, perform proof-of-concept experiments for major components, and design a shielded ship for human missions to Mars.

This study is led by Brianna Clements with Howe Industries in Scottsdale, Arizona.

The Great Observatory for Long Wavelengths (GO-LoW)

One of modern astronomy’s last frontiers is the low-frequency radio sky. Earth’s ionosphere blocks our ground-based telescopes from seeing it. And space-based telescopes can’t see it either. It’s because the wavelengths are so long, in the meter to the kilometre scale. Only extremely massive telescopes could see these waves clearly.

GO-LoW is a potential solution. It’s a space-based array of thousands of identical Small-Sats arranged as an interferometer. It would sit at an Earth-Sun Lagrange point and observe exoplanet and stellar magnetic fields. Exoplanet magnetic fields emit radio waves between 100 kHz and 15 MHz. The GO-LoW team says their interferometer could perform the first survey of exoplanetary magnetic fields within 5 parsecs (16 light years.) Magnetic fields tell scientists a lot about an exoplanet, its evolution, and its processes.

GO-LoW is a Great Observatory concept to open the last unexplored window of the electromagnetic (EM) spectrum. The Earth’s ionosphere becomes opaque at approximately 10m wavelengths, so GO-LoW will join Great Observatories like HST and JWST in space to access this spectral window. Image Credits: NASA/GO-LoW

While there’s no doubt that large telescopes like the JWST are powerful and effective, they’re extremely complex and expensive. And if something goes wrong with a critical component, the mission could end.

GO-LoW takes a different approach. By using thousands of individual satellites, the system is more resilient. GO-LoW would have a hybrid constellation. Some of the satellites would be smaller and simpler satellites called “listener nodes” (LN,) while a smaller number of them would be “communication and computation” nodes (CCNs). They would collect data from the LNs, process it, and beam it back to Earth.

The GO-LoW says it would only take a few heavy launches to place an entire 100,000 satellite constellation in space.

The technology for the SmallSats already exists. The challenge the GO-LoW team will address with their phase two funding is developing a system that will harness everything together effectively. “The coordination of all these physical elements, data products, and communications systems is novel and challenging, especially at scale,” they write.

GO-LoW is led by Mary Knapp with MIT in Cambridge, Massachusetts.

Radioisotope Thermoradiative Cell Power Generator

It’s sort of like solar power in reverse.

The RTCPG is a power source for spacecraft visiting the outer planets. They promise smaller, more efficient power generation for smaller science and exploration missions that can’t carry a solar power system or nuclear power system. Both those systems are bulky, and solar power is limited the further away from the sun a spacecraft goes.

The thermoradiative cell (TRC) uses radioisotopes to create heat as an MMRTG does. But the TRC uses the heat to generate infrared light which generates electricity. In initial testing, the system generated 4.5 times more power from the same amount of PU-238.

Much of phase two’s work will involve materials. “Metal-semiconductor contacts capable of surviving the required elevated temperatures will be investigated,” the team explains. The team developed a special cryostat testing apparatus in phase one.

“Building on our results from Phase I, we believe there is much more potential to unlock here,” the team writes.

This power generation concept study is from Stephen Polly at the Rochester Institute of Technology in New York.

FLOAT: Flexible Levitation on a Track

What if Artemis is enormously successful? How will astronauts move their equipment around the lunar surface efficiently?

If the team behind FLOAT has their way, they’ll build the Moon’s first railway. Sort of. This artist’s concept shows a possible future mission depicting the lunar surface with planet Earth on the horizon. Image Credit: Ethan Schaler

FLOAT would provide autonomous transportation for payloads on the Moon. “A durable, long-life robotic transport system will be critical to the daily operations of a sustainable lunar base in the 2030’s,” the FLOAT team writes.

The heart of FLOAT is a three-layer flexible track that’s unrolled into position without major construction. It consists of three layers: a graphite layer, a flex-circuit layer, and a solar panel layer.

The graphite layer allows robots to use diamagnetic levitation to float over the track. The flex-circuit layer supplies the thrust that moves them, and the thin-film solar panel layer generates electricity for a lunar base when it’s in sunlight.

The system can be used to move regolith around for in-situ resource utilization and to transport payloads around a lunar base, for example, from landing zones to habitats.

“Individual FLOAT robots will be able to transport payloads of varying shape/size (>30 kg/m^2) at useful speeds (>0.5m/s), and a large-scale FLOAT system will be capable of moving up to 100,000s kg of regolith/payload multiple kilometres per day,” the FLOAT team explains.

With their phase two funding, the FLOAT team intends to design, build, and test scaled-down versions of FLOAT robots and track. Then, they’ll test their system in a lunar analog testbed. They’ll also test environmental effects on the system and how they alter the system’s performance and longevity.

Ethan Schaler leads FLOAT at NASA’s Jet Propulsion Laboratory in Southern California.

SCOPE: ScienceCraft for Outer Planet Exploration

Some of the most intriguing planets and moons in the Solar System are well beyond Jupiter. But exploring them is challenging. Extremely long travel times, restrictive mission windows, and large expenses limit our exploration. But SCOPE aims to address these limitations.

Typically, a spacecraft carries a propulsion and power system along with its instruments and communication systems. NASA’s Juno mission to Jupiter, for example, carries a chemical rocket engine for propulsion, 50 square meters of solar panels, and 10 science instruments. The solar panels alone weigh 340 kg (750 lbs.) Juno is powerful, produces a wide variety of quality science data, and is expensive.

ScienceCraft takes a different approach. It combines a single science instrument and spacecraft into one monolithic structure. It’s basically a solar sail with a built-in spectrometer. They’re aiming their design at the Neptune-Triton system.

This artist’s depiction shows ScienceCraft, which integrates the science instrument with the spacecraft by printing a quantum dot spectrometer directly on the solar sail to form a monolithic, lightweight structure.
Image Credit: Mahmooda Sultana

“By printing an ultra-lightweight quantum dot-based spectrometer, developed by the PI Sultana, directly on the solar sail, we create a breakthrough spacecraft architecture allowing an unprecedented parallelism and throughput of data collection and rapid travel across the solar system,” the ScienceCraft team writes.

Instead of merely providing the propulsion, the sail doubles as the spacecraft’s science instrument. The small mass means that ScienceCraft could be carried into orbit as a secondary payload. The team says they’ll use phase two to identify and develop key technologies for the spacecraft and to further mature the mission concept. They say that because of the low cost and simplicity, they could be ready by 2045.

“By leveraging these benefits, we propose a mission concept to Triton, a unique planetary body in our solar system, within the short window that closes around 2045 to answer compelling science questions about Triton’s atmosphere, ionosphere, plumes and internal structure,” the ScienceCraft team explains.

ScienceCraft is led by NASA’s Mahmooda Sultana at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.

The post NASA Takes Six Advanced Tech Concepts to Phase II appeared first on Universe Today.

On Friday, May 3rd, the sixth mission in the Chinese Lunar Exploration Program (Chang’e-6) launched from the Wenchang Spacecraft Launch Site in southern China. Shortly after, China announced that the spacecraft separated successfully from its Long March 5 Y8 rocket. The mission, consisting of an orbiter and lander element, is now on its way to the Moon and will arrive there in a few weeks. By June, the lander element will touch down on the far side of the Moon, where it will gather about 2 kg (4.4 lbs) of rock and soil samples for return to Earth.

The mission launched four years after its predecessor, Chang’e-5, became China’s first sample-return mission to reach the Moon. It was also the first lunar sample return mission since the Soviet Luna 24 mission landed in Mare Crisium (the Sea of Crisis) in 1976. Compared to its predecessor, the Chang’e-6 mission weighs an additional 100 kg (220 lbs), making it the heaviest probe launched by the Chinese space program. The surface elements also face lesser-known terrain on the far side of the Moon and require a relay satellite for communications.

Speaking of surface elements, the China Academy of Space Technology (CAST) has since released images showing how the mission also carries a rover element. This payload was not part of mission data disclosed by China before the flight. But as SpaceNews’ Andrew Jones pointed out, the rover can be seen in the CAST images (see above) integrated onto the side of the lander.

Yeah, okay. That looks like a previously undisclosed mini rover on the side of the Chang'e-6 lander lol. Via CAST: https://t.co/gS0Jy5L9hw pic.twitter.com/9vvTnribpl

— Andrew Jones (@AJ_FI) May 3, 2024

“Little is known about the rover, but a mention of a Chang’e-6 rover is made in a post from the Shanghai Institute of Ceramics (SIC) under the Chinese Academy of Sciences (CAS),” he wrote. “It suggests the small vehicle carries an infrared imaging spectrometer.” This rover is no doubt intended to assist the lander with investigating resources on the far side of the Moon. This is consistent with China’s long-term plans for building the International Lunar Research Station (ILRS) around the southern polar region in collaboration with Roscosmos and other international patterns.

Similar to NASA’s plans for the Lunar Gateway and Artemis Base Camp, this requires that building sites be selected near sources of water ice and building materials (silica and other minerals). Ge Ping, the deputy director of the Center of Lunar Exploration and Space Engineering (CLESE) with the China National Space Administration (CNSA), related the importance of the sample-return mission to CGTN (a state-owned media company) before the launch:

“The Aitken Basin is one of the three major terrains on the Moon and has significant scientific value. Finding and collecting samples from different regions and ages of the Moon is crucial for our understanding of it. These would further study of the moon’s origin and its evolutionary history.”

In addition, the Chang’e-6 orbiter carries four international payloads and satellites including a French radon detector contributed by the ESA. Known as the Detection of Outgassing Radon (DORN), this payload will study how lunar dust and other volatiles (especially water) are transferred between the lunar regolith and the lunar exosphere. Then there’s the Italian INstrument for landing-Roving laser Retroreflector Investigations (INRRI), similar to those used by the Schiaparelli EDM module and InSight lander, that precisely measures distances from the lander to orbit.

The Chang’e-6 spacecraft stack shows a lunar rover attached to the mission lander. Credit: CAST

There’s also the Swedish Negative Ions on Lunar Surface (NILS), an instrument that will detect and measure negative ions reflected by the lunar surface. Lastly, there’s the Pakistani ICUBE-Q CubeSat developed by the Institute of Space Technology (IST) and Shanghai Jiao Tong University (SJTU), which will take images of the lunar surface using two optical cameras and measure the Moon’s magnetic field. The data these instruments provide will reveal new information about the lunar environment that will inform plans for long-duration missions on the surface.

By 2026, the Chang’e-6 mission will be joined by Chang’e-7, including an orbiter, lander, rover, and a mini-hopping probe. The data provided by the program will assist China’s plans to land taikonauts around the lunar south pole by 2030, followed by the completion of the ILRS by 2035.

Further Reading: CGTN

The post China is Going Back to the Moon Again With Chang'e-6 appeared first on Universe Today.

Earth is the only life-supporting planet we know of, so it’s tempting to use it as a standard in the search for life elsewhere. But the modern Earth can’t serve as a basis for evaluating exoplanets and their potential to support life. Earth’s atmosphere has changed radically over its 4.5 billion years.

A better way is to determine what biomarkers were present in Earth’s atmosphere at different stages in its evolution and judge other planets on that basis.

That’s what a group of researchers from the UK and the USA did. Their research is titled “The early Earth as an analogue for exoplanetary biogeochemistry,” and it appears in Reviews in Mineralogy. The lead author is Eva E. Stüeken, a PhD student at the School of Earth & Environmental Sciences, University of St Andrews, UK.

When Earth formed about 4.5 billion years ago, its atmosphere was nothing like it is today. At that time, the atmosphere and oceans were anoxic. About 2.4 billion years ago, free oxygen began to accumulate in the atmosphere during the Great Oxygenation Event, one of the defining periods in Earth’s history. But the oxygen came from life itself, meaning life was present when the Earth’s atmosphere was much different.

This isn’t the only example of how Earth’s atmosphere has changed over geological time. But it’s an instructive one and shows why searching for life means more than just searching for an atmosphere like modern Earth’s. If that’s the way we conducted the search, we’d miss worlds where photosynthesis hadn’t yet appeared.

In their research, the authors point out how Earth hosted a rich and evolving population of microbes under different atmospheric conditions for billions of years.

“For most of this time, Earth has been inhabited by a purely microbial biosphere albeit with seemingly increasing complexity over time,” the authors write. “A rich record of this geobiological evolution over most of Earth’s history thus provides insights into the remote detectability of microbial life under a variety of planetary conditions.”

It’s not just life that’s changed over time. Plate tectonics have changed and may have been ‘stagnant lid’ tectonics for a long time. In stagnant lid tectonics, plates don’t move horizontally. That can have consequences for atmospheric chemistry.

The main point is that Earth’s atmosphere does not reflect the solar nebula the planet formed in. Multiple intertwined processes have changed the atmosphere over time. The search for life involves not only a better understanding of these processes, but how to identify what stage exoplanets might be in.

This figure from the research shows how the abundance of major gases in Earth’s atmosphere has changed over time due to various factors. Image Credit: Stüeken et al. 2024.

It’s axiomatic that biological processes can have a dramatic effect on planetary atmospheres. “On the modern Earth, the atmospheric composition is very strongly controlled by life,” the researchers write. “However, any potential atmospheric biosignature must be disentangled from a backdrop of abiotic (geological and astrophysical) processes that also contribute to planetary atmospheres and would be dominating on lifeless worlds and on planets with a very small biosphere.”

The authors outline what they say are the most important lessons that the early Earth can teach us about the search for life.

The first is that the Earth has actually had three different atmospheres throughout its long history. The first one came from the solar nebula and was lost soon after the planet formed. That’s the primary atmosphere. The second one formed from outgassing from the planet’s interior. The third one, Earth’s modern atmosphere, is complex. It’s a balancing act involving life, plate tectonics, volcanism, and even atmospheric escape. A better understanding of how Earth’s atmosphere has changed over time gives researchers a better understanding of what they see in exoplanet atmospheres.

Earth’s Hadean Eon is a bit of a mystery to us because geologic evidence from that time is scarce. During the Hadean, Earth had its primary atmosphere from the solar nebula. But it soon lost it and accumulated another one via outgassing as the planet cooled. Credit: NASA

The second is that the further we look back in time, the more the rock record of Earth’s early life is altered or destroyed. Our best evidence suggests life was present by 3.5 billion years ago, maybe even by 3.7 billion years ago. If that’s the case, the first life may have existed on a world covered in oceans, with no continental land masses and only volcanic islands. If there had been abundant volcanic and geological activity between 3.5 and 3.7 billion years ago, there would’ve been large fluxes of CO2 and H2. Since these are substrates for methanogenesis, then methane may have been abundant in the atmosphere and detectable.

The third lesson the authors outline is that a planet can host oxygen-producing life for a long time before oxygen can be detected in an atmosphere. Scientists think that oxygenic photosynthesis appeared on Earth in the mid-Archean eon. The Archean spanned from 4 billion to 2.5 billion years ago, so mid-Archean is sometime around 3.25 billion years ago. But oxygen couldn’t accumulate in the atmosphere until the Great Oxygenation Event about 2.4 billion years ago. Oxygen is a powerful biomarker, and if we find it in an exoplanet’s atmosphere, it would be cause for excitement. But life on Earth was around for a long time before atmospheric oxygen would’ve been detectable.

Earth’s history is written in chemical reactions. This figure from the research shows the percentage of sulphur isotope fractionation in sediments. The sulphur signature disappeared after the GOE because the oxygen in the atmosphere formed an ozone shield. That blocked UV radiation, which stopped sulphur dioxide photolysis. “Anoxic planets where O2 production never occurs are more likely to resemble the early Earth prior to the GOE,” the authors explain. Image Credit: Stüeken et al. 2024.

The fourth lesson involves the appearance of horizontal plate tectonics and its effect on chemistry. “From the GOE onwards, the Earth looked tectonically similar to today,” the authors write. The oceans were likely stratified into an anoxic layer and an oxygenated surface layer. However, hydrothermal activity constantly introduced ferrous iron into the oceans. That increased the sulphate levels in the seawater which reduced the methane in the atmosphere. Without that methane, Earth’s biosphere would’ve been much less detectable. Complicated, huh?

“Planet Earth has evolved over the past 4.5 billion years from an entirely anoxic planet
with possibly a different tectonic regime to the oxygenated world with horizontal plate
tectonics that we know today,” the authors explain. All that complex evolution allowed life to appear and to thrive, but it also makes detecting earlier biospheres on exoplanets more complicated.

We’re at a huge disadvantage in the search for life on exoplanets. We can literally dig into Earth’s ancient rock to try to untangle the long history of life on Earth and how the atmosphere evolved over billions of years. When it comes to exoplanets, all we have is telescopes. Increasingly powerful telescopes, but telescopes nonetheless. While we are beginning to explore our own Solar System, especially Mars and the tantalizing ocean moons orbiting the gas giants, other solar systems are beyond our physical reach.

“We must instead remotely recognize the presence of alien biospheres and characterize their biogeochemical cycles in planetary spectra obtained with large ground- and space-based telescopes,” the authors write. “These telescopes can probe atmospheric composition by detecting absorption features associated with specific gases.” Probing atmospheric gases is our most powerful approach right now, as the JWST shows.

The JWST has made headlines for examining exoplanet atmospheres and identifying chemicals. A transmission spectrum of the hot gas giant exoplanet WASP-39 b, captured by Webb’s Near-Infrared Spectrograph (NIRSpec) on July 10, 2022, revealed the first definitive evidence for carbon dioxide in the atmosphere of a planet outside the Solar System. Credit: NASA, ESA, CSA, and L. Hustak (STScI). Science: The JWST Transiting Exoplanet Community Early Release Science Team

But as scientists get better tools, they’ll start to go beyond atmospheric chemistry. “We might also be able to recognize global-scale surface features, including light interaction with photosynthetic pigments and ‘glint’ arising from specular reflection of light by a liquid ocean.”

Understanding what we’re seeing in exoplanet atmospheres parallels our understanding of Earth’s long history. Earth could be the key to our broadening and accelerating search for life.

“Unravelling the details of Earth’s complex biogeochemical history and its relationship with remotely observable spectral signals is an important consideration for instrument design and our own search for life in the Universe,” the authors write.

The post What Can Early Earth Teach Us About the Search for Life? appeared first on Universe Today.

Multiple space agencies are looking to send crewed missions to the Moon’s southern polar region in this decade and the next. Moreover, they intend to create the infrastructure that will allow for a sustained human presence, exploration, and economic development. This requires that the local geography, resources, and potential hazards be scouted in advance and navigation strategies that do not rely on a Global Positioning System (GPS) developed. On Sunday, April 21st, the Chinese Academy of Sciences (CAS) released the first complete high-definition geologic atlas of the Moon.

This 1:2.5 million scale geological set of maps provides basic geographical data for future lunar research and exploration. According to the Institute of Geochemistry of the Chinese Academy of Sciences (CAS), the volume includes data on 12,341 craters, 81 impact basins, 17 types of lithologies, 14 types of structures, and other geological information about the lunar surface. This data will be foundational to China’s efforts in selecting a site for their International Lunar Research Station (ILRS) and could also prove useful for NASA planners as they select a location for the Artemis Base Camp.

Credit: CAS via Xinhua handout

Ouyang Ziyuan and Liu Jianzhong, a research professor and senior researcher from the Institute of Geochemistry of the CAS (respectively), oversaw these efforts. Since 2012, they have led a team of over 100 scientists and cartographers from relevant research institutions. The team spent more than a decade compiling scientific exploration data obtained by the many orbiters, landers, and rovers that are part of the Chinese Lunar Exploration Program (Chang’e), and other research about the origin and evolution of the Moon.

According to the CAS, the atlas includes an “upgraded lunar geological time scale” for “objectively” depicting the geological evolution of the Moon, including the lunar tectonics and volcanic activity that once took place. As a result, the volume could not only be significant in terms of lunar exploration and site selection. Still, it could also improve our understanding of the formation and evolution of Earth and the other terrestrial planets of the Solar System – Mercury, Venus, and Mars. As Jianzhong indicated in a CAS press release,

“The world has witnessed significant progress in the field of lunar exploration and scientific research over the past decades, which have greatly improved our understanding of the moon. However, the lunar geologic maps published during the Apollo era have not been changed for about half a century and are still being used for lunar geological research. With the improvements of lunar geologic studies, those old maps can no longer meet the needs of future scientific research and lunar exploration.”

Credit: CAS via Xinhua handout

Jianzhong also claims that the atlas could help inform future sample collection on the Moon. This includes the Chang’e-6 mission (consisting of an orbiter and lander), which launched this past Friday (May 3rd). The orbiter element will reach the Moon in a few weeks, and the lander element is expected to touch down the far side of the Moon by early June. By 2026, it will be joined by the Chang’e-7 mission, consisting of an orbiter, lander, rover, and a mini-hopping probe. While Chang’e-6 will obtain lunar soil and rock samples, Chang’e-7 will investigate resources and obtain samples of water ice and volatiles.

According to Gregory Michael, a senior scientist from the Free University of Berlin, the release of this atlas represents the culmination of decades of work, and not just by Chinese scientists:

“This map, in particular, is the first on a global scale to utilize all of the post-Apollo era data. It builds on the achievements of the international community over the last decades, as well as on China’s own highly successful Chang’e program. It will be a starting point for every new question of lunar geology and become a primary resource for researchers studying lunar processes of all kinds.”

Aside from updating data on lunar features and geology, the new maps reportedly double the resolution of the Apollo-era maps. These maps were compiled by the US Geological Survey in the 1960s and 70s using data from the Apollo missions. Among them was a global map at the scale of 1:5,000,000, though other regional maps and those that showed the terrain near the Apollo landing sites were of higher resolution. Geological and geographical information on the Moon has advanced considerably since then, requiring updated maps that reflect the objective of returning to the Moon with the intent to stay.

Credit: CAS via Xinhua handout

In addition to the Geologic Atlas of the Lunar Globe, the CAS also released a book called Map Quadrangles of the Geologic Atlas of the Moon. This document includes 30 sector diagrams that collectively form a visualization of the entire lunar surface. Both are available in Chinese and English, have been integrated into a digital platform called Digital Moon, and will eventually become available to the international research community.

Further Reading: CAS

The post China Creates a High-Resolution Atlas of the Moon appeared first on Universe Today.

Last November, NASA’s Lucy mission conducted a flyby of the asteroid Dinkinish, one of the Main Belt asteroids it will investigate as it makes its way to Jupiter. In the process, the spacecraft spotted a small moonlet orbiting the larger asteroid, now named Selam (aka. “Lucy’s baby”). The moonlet’s name, an Ethiopian name that means “peace,” pays homage to the ancient human remains dubbed “Lucy” (or Dinkinish) that were unearthed in Ethiopia in 1974. Using novel statistical calculations based on how the two bodies orbit each other, a Cornell-led research team estimates that the moonlet is only 2-3 million years old.

The research was led by Colby Merrill, a graduate student from the Department of Mechanical and Aerospace Engineering at Cornell. He was joined by Alexia Kubas, a researcher from the Department of Astronomy at Cornell; Alex J. Meyer, a Ph.D. student at the UC Boulder College of Engineering & Applied Science; and Sabina D. Raducan, a Postdoctoral Researcher at the University of Bern. Their paper, “Age of (152830) Dinkinesh-Selam Constrained by Secular Tidal-BYORP Theory,” recently appeared on April 19th in Astronomy & Astrophysics.

Merrill was also part of the NASA Double Asteroid Redirection Test (DART) mission, which collided with the moonlet Dimorphos on September 26th, 2022. As part of the Lucy mission, Merrill was surprised to discover that Dinkinesh was also a binary asteroid when the spacecraft flew past it on November 1st, 2023. They were also fascinated to learn that the small moonlet was a “contact binary,” consisting of two lobes that are piles of rubble that became stuck together long ago.

Artist’s Rendering of NASA’s Lucy mission, which will study asteroids within the Main Belt and Jupiter’s Trojan population. Credit: Southwest Research Institute

While astronomers have observed contact binaries before – a good example is the KBO Arrokoth that the New Horizons spacecraft flew past on January 1st, 2019 – this is the first time one has been observed orbiting a larger asteroid. Along with Kubas, the two began modeling the system as part of their studies at Cornell to determine the age of the moonlet. Their results agreed with one performed by the Lucy mission based on an analysis of surface craters, the more traditional method for estimating the age of asteroids. As Merrill said in a recent Cornell Chronicle release:

“Finding the ages of asteroids is important to understanding them, and this one is remarkably young when compared to the age of the Solar System, meaning it formed somewhat recently. Obtaining the age of this one body can help us to understand the population as a whole.”

Binary asteroids are a subject of fascination to astronomers because of the complex dynamics that go into creating them. On the one hand, there are the gravitational forces working on them that cause them to bulge and lose energy. At the same time, binary systems will also experience what is known as the Binary Yarkovsky–O’Keefe–Radzievskii–Paddack (BYORP) effect, where exposure to solar radiation alters the rotation rate of the bodies. Eventually, these forces will balance out and reach a state of equilibrium for the system.

For their study, Merril and his team assumed that Selam formed from material ejected from Dinkinesh before the BYORP effect slowed its rotation down. They also assumed that the system had since reached a state of equilibrium and that the density of both objects was comparable. They then integrated asteroid data obtained by the Lucy mission to calculate how long it would take Selam to reach its current state. After performing about 1 million calculations with varying parameters, they obtained a median age estimate of 3 million years old, with 2 million being the most likely result.

Artist’s impression of the DART mission impacting the moonlet Dimorphos. Credit: ESA

This new method complements the previous age estimates of the Lucy mission and has several advantages. As their paper indicates, this method can yield age estimates based on asteroid dynamics alone and does not require close-up images taken by spacecraft. It could also be more accurate where asteroid surfaces experienced recent changes and can be applied to the moonlets of other known binary systems, which account for 15% of near-Earth asteroids (NEAs). This includes Didymos and Dimorphos, which are even younger.

The researchers hope to apply their new method to this and other binary systems where the dynamics are well-characterized, even without close flybys. Said Kubas:

“Used in tandem with crater counting, this method could help better constrain a system’s age. If we use two methods and they agree with each other, we can be more confident that we’re getting a meaningful age that describes the current state of the system.”

Further Reading: Cornell Chronicle

The post Dinkinesh's Moonlet is Only 2-3 Million Years Old appeared first on Universe Today.

It’s that time again! Time for another model that will finally solve the mystery of dark matter. Or not, but it’s worth a shot. Until we directly detect dark matter particles, or until some model conclusively removes dark matter from our astrophysical toolkit the best we can do is continue looking for solutions. This new work takes a look at that old theoretical chestnut, primordial black holes, but it has a few interesting twists.

Primordial black holes are hypothetical objects formed during the earliest moments of the Universe. According to the models they formed from micro-fluctuations in matter density and spacetime to become sandgrain-sized mountain-massed black holes. Although we’ve never detected primordial black holes, they have all the necessary properties of dark matter, such as not emitting light and the ability to cluster around galaxies. If they exist, they could explain most of dark matter.

The downside is that most primordial black hole candidates have been ruled out by observation. For example, to account for dark matter there would have to be so many of these gravitational pipsqueaks that they would often pass in front of a star from our vantage point. This would create a microlensing flare we should regularly observe. Several sky surveys have looked for such an event to no avail, so PBH dark matter is not a popular idea these days.

This new work takes a slightly different approach. Rather than looking at typical primordial black holes, it considers ultralight black holes. These are on the small end of possible masses and are so tiny that Hawking radiation would come into play. The rate of Hawking decay is inversely proportional to the size of a black hole, so these ultralight black holes should radiate to their end of life on a short cosmic timescale. Since we don’t have a full model of quantum gravity, we don’t know what would happen to ultralight black holes at the end, which is where this paper comes in.

Observational limits for primordial black holes. Credit: S. Profumo

As the author notes, basically there are three possible outcomes. The first is that the black hole radiates away completely. The black hole would end as a brief flash of high-energy particles. The second is that some mechanism prevents complete evaporation and the black hole reaches some kind of equilibrium state. The third option is similar to the second, but in this case, the equilibrium state causes the event horizon to disappear, leaving an exposed dense mass known as a naked singularity. The author also notes that for the latter two outcomes, the objects might have a net electric charge.

For the evaporating case, the biggest unknown would be the timescale of evaporation. If PBHs are initially tiny they would evaporate quickly and add to the reheating effect of the early cosmos. If they evaporate slowly, we should be able to see their deaths as a flash of gamma rays. Neither of these effects has been observed, but it is possible that detectors such as Fermi’s Large Area Telescope might catch one in the act.

For the latter two options, the author argues that equilibrium would be reached around the Planck scale. The remnants would be proton sized but with much higher masses. Unfortunately, if these remnants are electrically neutral they would be impossible to detect. They wouldn’t decay into other particles, nor would they be large enough to detect directly. This would match observation, but isn’t a satisfying result. The model is essentially unprovable. If the particles do have a charge, then we might detect their presence in the next generation of neutrino detectors.

The main thing about this work is that primordial black holes aren’t entirely ruled out by current observations. Until we have better data, this model joins the theoretical pile of many other possibilities.

Reference: Profumo, S. “Ultralight Primordial Black Holes.” arXiv preprint arXiv:2405.00546 (2024).

The post The Universe Could Be Filled With Ultralight Black Holes That Can't Die appeared first on Universe Today.

NASA has given the go-ahead for SpaceX to work out a plan to adapt its Starlink broadband internet satellites for use in a Martian communication network.

The idea is one of a dozen proposals that have won NASA funding for concept studies that could end up supporting the space agency’s strategy for bringing samples from Mars back to Earth for lab analysis. The proposals were submitted by nine companies — also including Blue Origin, Lockheed Martin, United Launch Alliance, Astrobotic, Firefly Aerospace, Impulse Space, Albedo Space and Redwire Space.

Awardees will be paid $200,000 to $300,000 for their reports, which are due in August. NASA says the studies could lead to future requests for proposals, but it’s not yet making any commitment to follow up.

“We’re in an exciting new era of space exploration, with rapid growth of commercial interest and capabilities,” Eric Ianson, director of NASA’s Mars Exploration Program, said in a news release. “Now is the right time for NASA to begin looking at how public-private partnerships could support science at Mars in the coming decades.”

For years, SpaceX executives have been talking about using Starlink satellites in Martian orbit as part of billionaire founder Elon Musk’s vision of making humanity a multiplanetary species. In 2020, SpaceX President Gwynne Shotwell told Time magazine that connectivity will be an essential part of the company’s Mars settlement plan.

“Once we take people to Mars, they are going to need a capability to communicate,” she said. “In fact, I think it will be even more critical to have a constellation like Starlink around Mars. And then, of course, you need to connect the two planets as well — so, we need to make sure we have robust telecom between Mars and back in Earth.”

Musk delved into more detail during last October’s International Astronautical Congress in Azerbaijan. “For Mars, you’d want a laser relay system, essentially,” he said. “It depends on what bandwidth you’re looking for. … Ultimately, we’d want terabit, maybe petabit-level data transfer between Earth and Mars.” Check out his comments on YouTube:

Musk could capitalize on NASA’s need to upgrade its communication relay system at the Red Planet, which relies on satellites that are up to 23 years old. The space agency’s main focus for future Mars exploration is its multi-mission strategy to retrieve samples that have been cached by the Perseverance rover. Last month, NASA said it would rework that strategy to reduce costs, in part by taking advantage of innovations coming from private industry. The innovations that are now the focus of the Mars Exploration Commercial Services program could play prominent roles in the revised strategy.

Blue Origin, the space venture founded by Amazon billionaire Jeff Bezos, will look into adapting its Blue Ring transfer vehicle to host and deliver payloads heading for Mars. A separate study will focus on Blue Ring’s potential use for next-generation relay services. In a posting to X / Twitter, Blue Origin said it was “excited to be part of NASA’s studies around the future of Mars robotic science and the unique benefits our Blue Ring platform can provide by enabling large payload delivery, hosting, and next-gen relay services.”

Here are the other companies on NASA’s list, and the subjects of their studies:

• Albedo Space: How to adapt an imaging satellite originally meant for low Earth orbit to provide Mars surface imaging.
• Astrobotic Technology: How to modify a lunar-exploration spacecraft for large payload delivery and hosting services. Also, how to modify a lunar-exploration spacecraft for Mars surface imaging.
• Firefly Aerospace: How to adapt a lunar-exploration spacecraft for small payload delivery and hosting services.
• Impulse Space: How to adapt its Helios space tug to provide small payload delivery and hosting for Mars missions.
• Lockheed Martin: How to adapt a lunar-exploration spacecraft for small payload delivery and hosting. Also, how to provide communication relay services for Mars with a spacecraft originally meant for use in the vicinity of Earth and the moon.
• Redwire Space: How to modify a commercial imaging spacecraft originally meant for low Earth orbit to provide Mars surface-imaging services.
• United Launch Alliance (through United Launch Services): How to modify an Earth-vicinity cryogenic upper stage to provide large payload delivery and hosting services.

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The JWST is astronomers’ best tool for probing exoplanet atmospheres. Its capable instruments can dissect the light passing through a distant world’s atmosphere and determine its chemical components. Scientists are interested in everything the JWST finds, but when it finds something indicating the possibility of life it seizes everyone’s attention.

That’s what happened in September 2023, when the JWST found dimethyl sulphide (DMS) in the atmosphere of the exoplanet K2-18b.

K2-18b orbits a red dwarf star about 124 light-years away. It’s a sub-Neptune with about 2.5 times Earth’s radius and 8.6 Earth masses. The exoplanet may be a Hycean world, a temperate ocean-covered world with a large hydrogen atmosphere.

In October 2023, researchers announced the tentative detection of dimethyl sulphide in K2-18b’s atmosphere. They found it in JWST observations of the planet’s atmospheric spectrum. “The spectrum also suggests potential signs of dimethyl sulphide (DMS), which has been predicted to be an observable biomarker in Hycean worlds, motivating considerations of possible biological activity on the planet,” the researchers wrote.

The DMS caught people’s attention because it’s produced by living organisms here on Earth, mostly by marine microbes. So, finding it on an ocean world is cause for a deeper look. A team of researchers from the USA, Germany, and the UK examined the detection to see how it fits with atmospheric models.

“The best biosignatures on an exoplanet may differ significantly from those we find most abundant on Earth today.”

Eddie Schwieterman, astrobiologist, University of California, Riverside

They published their results in a paper in the Astrophysical Journal Letters. It’s titled “Biogenic Sulfur Gases as Biosignatures on Temperate Sub-Neptune Waterworlds.” The lead author is Shang-Min Tsai, a University of California Riverside project scientist.

Most of the thousands of exoplanets we’ve discovered are nothing like Earth. Habitability is impossible according to every known metric. But some are more intriguing. Some, like K2-18b, are more difficult to understand regarding habitability.

There’s some disagreement over what type of planet K2-18b is. It was the first exoplanet scientists ever detected water vapour on. It may be the first example of a Hycean world if they exist.

Artist depiction of the mini-Neptune K2-18 b. Credit: NASA, CSA, ESA, J. Olmstead (STScI), N. Madhusudhan (Cambridge University)

There are some clear differences between K2-18b and Earth. Our atmosphere is dominated by nitrogen, which makes up about 78%. K2-18b’s atmosphere is dominated by hydrogen. But it’s enough like Earth in some ways that scientists are keen to understand it better.

“This planet gets almost the same amount of solar radiation as Earth. And if atmosphere is removed as a factor, K2-18b has a temperature close to Earth’s, which is also an ideal situation in which to find life,” said lead author Shang-Min Tsai.

The researchers who found DMS in K2-18b’s atmosphere also found carbon dioxide and methane. Finding CO2 and CH4 is noteworthy, but finding DMS with them is even more intriguing.

“What was icing on the cake, in terms of the search for life, is that last year these researchers reported a tentative detection of dimethyl sulfide, or DMS, in the atmosphere of that planet, which is produced by ocean phytoplankton on Earth,” Tsai said. DMS is oxidized in Earth’s oceans and is the planet’s main source of atmospheric sulphur.

K2-18b’s atmospheric composition as measured by the JWST’s near-infrared instruments. The detection of Dimethyl Sulphide is not holding up under increased scrutiny. Image Credit: NASA/CSA/ESA/STScI

However, the 2023 findings were not conclusive. There were hints of DMS but nothing strong enough to convince scientists and overcome their professional skepticism. “The potential inference of DMS is of high importance, as it is known to be a robust biomarker on Earth and has been extensively advocated to be a promising biomarker for exoplanets,” the authors of the 2023 paper explained.

“The DMS signal from the Webb telescope was not very strong and only showed up in certain ways when analyzing the data,” Tsai said. “We wanted to know if we could be sure of what seemed like a hint about DMS.”

The JWST has no alarm bell and flashing indicator that lights up and says, ‘Biomarker Detected!’ It produces data that must be processed to tease out its secrets. Scientists also rely on battle-tested climate and atmospheric chemistry models to understand what the JWST sees.

“In this study, we explore biogenic sulphur across a wide range of biological fluxes and stellar UV environments,” the researchers write. They performed experiments with a 2D photochemical model and a 3D general circulation model (GCM.) According to Tsai and his co-researchers, the data is unlikely to show the presence of DMS in K2-18b’s atmosphere.

“The signal strongly overlaps with methane, and we think that picking out DMS from methane is beyond this instrument’s capability,” Tsai said.

That doesn’t mean that DMS is ruled out. It’s possible that the chemical could build up to detectable levels if plankton or some other life form were producing it. But, they’d have to produce about 20 times more DMS than there is on Earth.

Professor Madhusudhan from Cambridge University is the lead author of the 2023 paper on K2-18b’s atmosphere. He’s being touted in the media as the man who discovered alien life on another planet. He’s clearly uncomfortable with some of the hyperbole, but the message is becoming bigger than the messenger.

This study will probably put a damper on the media’s enthusiasm. But for people who follow science, this is just another instance of science correcting itself.

The fact is, we’re only groping our way toward understanding exoplanet atmospheres. Scientists have a powerful tool in the JWST, but it has limitations. It measures light in extreme detail and leaves the rest up to us. “We find that it is challenging to identify DMS at 3.4 ?m where it strongly overlaps with CH4,” the authors explain. But, they continue, “it is more plausible to detect DMS … in the mid-infrared between 9 and 13 ?m,” the authors explain.

This figure from the research compares how detectable DMS is in NIR (left) vs MIR (right.) We’re mostly interested in the 20xSorg (20 x organic sulphur.) Its presence at that concentration is muddy in NIR but stands out more clearly in simulated MIR data. Image Credit: Left: Madhusudhan et al. 2023. Right: Batalha et al. 2017.

That means there’s hope for K2-18b. These observations were taken with the JWST’s near-infrared instruments, the NIRISS and the NIRSpec. Sometime next year, the JWST will examine the exoplanet’s atmosphere again, this time with its mid-infrared instrument MIRI. This instrument should tell us definitively whether DMS is present.

This figure shows the wavelength ranges of its instruments and the modes available to them. Image Credit: NASA/STScI

Scientists’ understanding of biosignatures has grown more detailed. Instead of searching for biosignatures like the ones on Earth, scientists are taking a larger, more holistic view of biosignatures and the nature of the atmospheres they might be present in.

“The best biosignatures on an exoplanet may differ significantly from those we find most abundant on Earth today. On a planet with a hydrogen-rich atmosphere, we may be more likely to find DMS made by life instead of oxygen made by plants and bacteria as on Earth,” said UCR astrobiologist Eddie Schwieterman, a senior author of the study.

The team’s work does show that sulphur could be a detectable biomarker for Hycean worlds. “The moderate threshold for biological production suggests that the search for biogenic sulphur gases as one class of potential biosignature is plausible for Hycean worlds,” they conclude.

The post Did You Hear Webb Found Life on an Exoplanet? Not so Fast… appeared first on Universe Today.

First light for the Vera Rubin Observatory (VRO) is quickly approaching and the telescope is reaching milestone after milestone. A few weeks ago, the observatory announced that its digital camera, the largest one ever made, is complete.

Now the observatory has announced that its unique primary/tertiary mirror has its first reflective coating.

The Rubin’s massive digital camera has an important job and garners a lot of attention. But it’s powerless without the telescope’s innovative primary/tertiary mirror. Primary mirrors are always the most critical and time-consuming part of modern observatories. The VRO’s primary/tertiary mirror took seven years to make.

The mirror is called a primary/tertiary mirror because it comprises two optical surfaces with different curvatures. The primary mirror is 8.4 meters, while the tertiary mirror is 5 meters in diameter. The pair of surfaces are combined into one large structure. The unique design reduces the telescope’s engineering complexity without reducing its impressive light-gathering capability. It can be rotated quickly and also settles quickly.

The VRO’s unique primary/tertiary mirror is two mirrors in one. It’s mounted on lightweight honeycomb material for strength. Image Credit: VRO

The outer surface forms the primary mirror. It captures light from space first, then that light reflects upwards to the 3.4-meter secondary mirror. After that, it’s reflected back down to the inner 5.0-meter surface that forms the tertiary mirror. Then, the light is sent to the camera.

The primary mirror’s size is critical because it determines how much light the telescope can collect. More light means astronomers can study very faint or distant objects. The VRO’s design allows the camera to capture a large area of sky the size of 7 full moons across in a single image.

via GIPHY

Only meticulous engineering and construction can build a telescope like this. One of the stages is putting the reflective and protective coatings on the mirrors. The VRO announced that the primary/tertiary mirror has its first coating.

“This was a very well-conducted project from every angle, thanks to a combination of careful planning and the technical skills of our excellent team.”

Tomislav Vucina, Senior Coating Engineer, VRO

The VRO has a special onsite coating chamber built just for this purpose. It’s a 128-ton chamber on the observatory’s maintenance floor. It uses a process called magnetron sputtering to apply coatings. The chamber will be reused during the telescope’s lifetime whenever the mirror needs re-coating.

The chamber can apply coatings of different reflective materials alone or in combinations. It took a lot of work to determine the perfect coating for reflectivity and durability. Researchers tested different coatings on a steel stand-in mirror.

The first layer was an adhesive layer of nickel-chromium. Next came an incredibly thin layer of silver weighing only 64 grams spread over the 8.4-meter mirror. On top of that, another nickel-chromium adhesive layer, then a protective layer of silicon nitride to shield the reflective layer.

The person in charge of these precision coatings is Tomislav Vucina, the Senior Coating Engineer. Vucina describes the coatings as a balancing act. “This outer layer needs to be thick enough that it’s not worn off by cleaning,” said Vucina, “but not so thick that it absorbs too many photons and prevents the mirror from meeting Rubin’s scientific requirements.”

This image shows the Rubin Observatory’s 8.4-meter combined primary/tertiary mirror after being coated with protected silver in April 2024. The reflective coating was applied using the observatory’s onsite coating chamber, which will also be used to re-coat the mirror as necessary during Rubin’s 10-year Legacy Survey of Space and Time. Image Credit: RubinObs/NOIRLab/NSF/AURA

Until these coatings were applied, the glass was just glass. Highly specialized glass, but glass nonetheless. Now that the glass has received its reflective silver coating, it’s truly a mirror.

The application process took only 4.5 hours, nothing compared to the 7 years required to build the primary/tertiary mirror. Vucina and his team subjected the mirror to a battery of tests: reflectivity, adhesion, pinhole, and cosmetic. According to Vucina, the application process was successful.

“This was a very well-conducted project from every angle,” said Vucina, “thanks to a combination of careful planning and the technical skills of our excellent team.”

It’s been a long road to completion for the VRO. But after a long wait, first light is rapidly approaching. Excitement and anticipation for the observatory’s unique and powerful scientific contribution is growing. Its main output is the decade-long Legacy Survey of Space and Time.

“We’re extremely excited that both mirrors are now coated and will be installed on the telescope very soon,” said Sandrine Thomas, Deputy Director for Rubin Construction. “The combined reflectivity of these mirrors will enable Rubin to detect very faint and far-away objects, leading to great science!”

The post Vera Rubin’s Primary Mirror Gets its First Reflective Coating appeared first on Universe Today.

A beautiful nebula in the southern hemisphere with a binary star at it’s center seems to break our standard models of stellar evolution. But new data from the European Southern Observatory (ESO) suggests that there may once have been three stars, and that one was destroyed in a catastrophic collision.

About 3800 light years away, in the Southern constellation of Norma, you can find an object called the Dragon’s Egg Nebula (catalogue number NGC 6164). In the heart of this nebula lies a double star known as HD 148937. The pair are bright enough to be seen through binoculars and small telescopes but are far enough away that they only appear as a single star. Both of the stars that make up the pair are hot young blue giants, but the nebula surrounding them is quite unusual, which is why astronomers have been studying them for a long time.

Dr Abigail Frost is an astronomer at the European Southern Observatory (ESO) in Chile, and she has been paying attention to this system for the past nine years.

“When doing background reading, I was struck by how special this system seemed,” she says. “A nebula surrounding two massive stars is a rarity, and it really made us feel like something cool had to have happened in this system. When looking at the data, the coolness only increased.”

Frost, like other astronomers before her, have noticed many strange features about the nebula. Most obviously, hot young stars like these aren’t usually found in nebulae, as their intense radiation tends to disperse surrounding dust and gas quite efficiently. But beyond that, the nebula itself has an unusual composition. If this nebula were the remains of the gas cloud that birthed these stars, it would be composed almost entirely of molecular hydrogen. But instead, it contains heavier elements like oxygen, nitrogen and carbon. Old stars create these elements by fusing Helium, and they eject them in their final stages of life. But that cannot be the source of this nebula, as the stars are still young.

The stars themselves have their own mysteries. The larger of the two has a strong magnetic field. Magnetic fields in stars like our Sun are formed when the thick central shell of super-heated plasma circulates. Much of the heat from the Sun’s core is transferred to the surface by convection: hot plasma near the core bubbles up towards the surface, where it cools and then sinks back down. Plasma is electrically charged, and all that charge moving generates a magnetic field, in what scientists call a dynamo effect.

But truly massive stars, like those in HD 148937, are so big that heat can simply radiate out from the core. There is such a large distance from the core to the surface that the temperature gradient is very gradual. There is nowhere inside the star with a high enough temperature differential to start convection, so there is no flow of material to generate a magnetic field. Nevertheless, the star has a magnetic field, which leads to the next oddity: magnetic stars experience a braking effect, causing their spin to gradually slow. So, this star, with its strong magnetic field which it should not have, spins rapidly, which the magnetic field should have prevented.

Fighting Dragons of Ara (NGC 6188 and 6164) © Michael Sidonio

But that’s not all! The primary star is at least 1.5 million years younger than its companion. According to Dr Frost, this shouldn’t be possible: “After a detailed analysis, we could determine that the more massive star appears much younger than its companion, which doesn’t make any sense since they should have formed at the same time”

If this system of stars and nebula doesn’t match what our models of stellar evolution tell us to expect, then how do we explain all these anomalies?

“We think this system had at least three stars originally; two of them had to be close together at one point in the orbit whilst another star was much more distant,” explains Hugues Sana, a professor at KU Leuven in Belgium and the principal investigator of the observations. “The two inner stars merged in a violent manner, creating a magnetic star and throwing out some material, which created the nebula. The more distant star formed a new orbit with the newly merged, now-magnetic star, creating the binary we see today at the centre of the nebula.”

In other words, the system was originally a triple star, not a double. Triple systems tend to be quite unstable, and usually end up ejecting one of their members. But sometimes the third star will smash dramatically into one of its companions instead. Nobody has ever seen a stellar collision, but computer modelling predicts a number of things, which we see in NGC 6164. A star is, essentially, a vast and massive cloud of gas, so big and heavy that its central regions are compressed to an enormous temperature and pressure. So, when two stars collide, these masses of gas merge chaotically. The different layers mix, dredging nuclear ash (like helium, nitrogen, carbon and oxygen) from the core to the surface. A lot of the gas, including the heavier elements, is ejected to create a vast new nebula. What’s left will collapse back inwards, settling down into a new star, with a rapid spin to match. And finally, the turbulence of the collision generates and sustains a powerful magnetic field.

This sequence of events has long been predicted by astronomers trying to model stellar mergers, and the nine years of work by Dr Frost could well provide the evidence to confirm that they are right. The metal-rich gas of NGC 6164, the youthful appearance of the primary star, it’s rapid spin and strong magnetic field all seem to confirm that this was indeed once a three body system that ended with a collision between two stars.

Read the original press release at https://www.eso.org/public/news/eso2407/

The post Two Stars in a Binary System are Very Different. It's Because There Used to be Three appeared first on Universe Today.

The history of astronomy and observatories is full of stories about astronomers going higher and higher to get better views of the Universe. On Earth, the best locations are at places such as the Atacama Desert in Chile. So, that’s where the University of Tokyo Atacama Observatory just opened its high-altitude eye on the sky, atop Cerro Chajnantor.

This unique new observatory, which was just commissioned on April 30th, sits at 5,640 meters (3.5 miles) above sea level, making it the highest observatory in the world—with a Guinness World Record recognition to prove it. The idea is to use this position in one of the driest areas of the world to get a closer look at planet-forming regions, evolving galaxies, and the earliest accessible epochs of cosmic history.

“Thanks to the height and arid environment, TAO will be the only ground-based telescope in the world capable of clearly viewing mid-infrared wavelengths. This area of the spectrum is extremely good for studying the environments around stars, including planet-forming regions,” said Professor Takashi Miyata, director of the Atacama Observatory of the Institute of Astronomy and manager of the observatory’s construction.

Building an observatory at such a high altitude may give astronomers a great view, but it’s also is a difficult place to work. For that reason, the University cooperated closely with locals to build the observatory safely. It will be operated remotely as much as possible, to avoid risking human life in what can be very adverse conditions.

At 5,640 meters, the summit of Cerro Chajnantor, where Tokyo Atacama Observatory is located, allows the telescope to be above most of the moisture that would otherwise limit its infrared sensitivity. ©2024 TAO project CC-BY-ND Why a Mid-infrared Observatory?

Objects and events in the Universe give off light across the electromagnetic spectrum. On Earth, we can detect much of that light, but not all of it. For example, Earth’s atmosphere absorbs many infrared wavelengths. So, the higher a telescope is placed, the more infrared it can “see”. Going to space (as astronomers have done with JWST, for example) is great, and a lot gets accomplished there. But astronomers can do quite a lot of very good astronomy at high altitudes, where conditions are dry and the atmosphere is thinner.

Mid-infrared is a particularly interesting “regime” of the electromagnetic spectrum. This is where we can start to “see” objects such as asteroids and planets. They re-radiate heat from their stars in the mid-infrared range. The same thing happens with dust around stars. It gets warmed and re-radiates in the mid-infrared. Disks of material around newborn stars—called protoplanetary disks—give off infrared radiation. Since these disks are where new planets form, infrared views give more detail about their evolution.

Mid-infrared studies of distant galaxies offer insight into their formation histories, as well as their star-formation rates. In addition, that range of wavelengths opens up a window into the activities and existence of active galactic nuclei. And, there’s a lot more that mid-infrared observations of the Universe can tell astronomers.

TAO Specs

According to Professor Yuzuru Yoshii, the TAO project lead and principal investigator, the new observatory should provide unique insights at each wavelength it studies. “I’m seeking to elucidate mysteries of the Universe, such as dark energy and primordial first stars,” said Yoshii. “For this, you need to view the sky in a way that only TAO makes possible.”

A schematic of the Tokyo Atacama Observatory telescope. Courtesy TAO project.

The heart of TAO is a 6.5-meter mirror that will feed incoming light into specialized instruments. The Simultaneous-color Wide-field Infrared Multi-object Spectrograph (SWIMS) can observe a large area of the sky and simultaneously observe two wavelengths of light. The other is the Mid-Infrared Multi-field Imager for gaZing at the UnKnown Universe (MIMIZUKU). It peers into the dustier regions of the Universe. Both will allow astronomers to efficiently collect information on a diverse range of galaxies and other structures in the Universe.

“Analysis of the SWIMS observation data will provide insight into the formation of these including the evolution of the supermassive black holes at their centers,” said Assistant Professor Masahiro Konishi. “New telescopes and instruments naturally help advance astronomy. I hope the next generation of astronomers use TAO and other ground-based, and space-based, telescopes, to make unexpected discoveries that challenge our current understanding and explain the unexplained.”

For More Information

The TAO Project
World’s Highest Observatory Explores the Universe

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The JWST keeps one-upping itself. In the telescope’s latest act of outdoing itself, it examined a distant exoplanet to map its weather. The forecast?

An unending, blistering inferno driven by ceaseless supersonic winds.

WASP-43b is a hot Jupiter orbiting a main sequence star about 261 light-years away. It has a slightly larger radius than Jupiter and is about twice as massive. It orbits its star in under 20 hours and is only 1.3 million miles away from it. That means it is tidally locked to the star, with one side facing all the radiation and the other permanently dark.

This is not unusual for exoplanet gas giants. They’re often tight to their stars and don’t rotate.

WASP-43b’s discovery was announced in 2011. Since then, astronomers have studied it extensively. In 2019, researchers captured its spectrum and reported water in its clouds. Conversely, no methane, carbon dioxide, or carbon monoxide were detected. Further research showed that mineral particles dominate its clouds. The Hubble Space Telescope was largely responsible for these results; other telescopes like the Spitzer also contributed.

Scientists knew that when the JWST was launched, it would eventually turn its eye toward WASP-43b. “Having a short orbital period and being tidally locked makes WASP-43b an ideal candidate for JWST observations,” explained the authors of a 2020 paper. “Phase curve observations of an entire orbit will enable the mapping of the atmospheric structure across the planet, with different wavelengths of observation allowing different atmospheric depths to be seen.” Their paper anticipated what the JWST might find and how its observations might be understood.

Now, we’re in the future, and the JWST has taken a look at WASP-43b and captured more detailed observations than ever. The space telescope’s powerful infrared capabilities measured the heat on both sides of the planet and allowed the mapping of the planet’s atmospheric structure, just as the authors of the 2020 paper stated.

“The fact that we can map temperature in this way is a real testament to Webb’s sensitivity and stability.”

Michael Roman, University of Leicester.

A new paper in Nature Astronomy presents the results. It’s titled “Nightside Clouds and Disequilibrium Chemistry on the Hot Jupiter WASP-43b.” The lead author is Taylor Bell, a researcher from the Bay Area Environmental Research Institute.

“With Hubble, we could clearly see that there is water vapour on the dayside. Both Hubble and Spitzer suggested there might be clouds on the nightside,” explained lead author Bell. “But we needed more precise measurements from Webb to really begin mapping the temperature, cloud cover, winds, and more detailed atmospheric composition all the way around the planet.”

Despite its power, the JWST can’t directly see WASP-43b. Instead, it utilizes phase curve spectroscopy. Phase curve spectroscopy measures the light from the planet and the star over time, sensing small changes in the light from both as the planet orbits the star. Since the JWST senses infrared light, which is emitted depending on an object’s heat, the telescope’s varying brightness data expresses the planet’s temperature.

Phase curve spectroscopy allows the JWST to sense the change in brightness as a planet orbits its star. This diagram shows the change in a planet’s phase (the amount of the lit side facing the telescope) as it orbits its star. Image Credit: NASA, ESA, CSA, Dani Player (STScI), Andi James (STScI), Greg Bacon (STScI)

The JWST’s MIRI spectrometer captured WASP-43b’s phase curve. The planet is hottest when it’s on the opposite side of the star and its lit-up side faces the telescope. The telescope sees the cooler dark side when the planet is on this side of the star and transiting in front of it.

This graph shows more than 8,000 measurements of mid-infrared light captured over a single 24-hour observation using the JWST’s low-resolution spectroscopy mode on its MIRI (Mid-Infrared Instrument). By subtracting the amount of light the star contributes, astronomers can calculate the amount coming from the visible side of the planet as it orbits. The telescope’s extreme sensitivity made this possible. Webb detected differences in brightness as small as 0.004% (40 parts per million). Image Credit: NASA, ESA, CSA, Ralf Crawford (STScI)

“By observing over an entire orbit, we were able to calculate the temperature of different sides of the planet as they rotate into view,” explained Bell. “From that, we could construct a rough map of temperature across the planet.”

To put the data into perspective, the researchers compared WASP-43b’s phase curve to General Circulation Model (GCM) simulations. The JWST phase curve data more closely matched a cloudy GCM than a cloudless GCM.

“The cloudy models are able to suppress the nightside emission and better match the data,” the authors explain in their paper.

This figure from the research shows the JWST’s phase curve data for WASP-43b (black dots) and what cloudless and cloudy GCM simulations predict. The data more closely matches a cloudy atmosphere. Image Credit: Bell et al. 2024.

The researchers used the detailed infrared data to construct a temperature map of the exoplanet. The dayside has an average temperature of about 1,250 Celsius (2,300 F), which is almost hot enough to forge iron. But the nightside likely has a thick layer of high-altitude clouds that trap some of the heat. Those clouds make the nightside appear cooler than it is. It’s much cooler at about 600 degrees Celsius (1,100 degrees Fahrenheit) but still hot enough to melt aluminum.

“The fact that we can map temperature in this way is a real testament to Webb’s sensitivity and stability,” said Michael Roman, a co-author from the University of Leicester in the U.K.

This set of maps shows the temperature of the visible side of the hot gas-giant exoplanet WASP-43 b as the planet orbits its star. Image Credits: Illustration: NASA, ESA, CSA, Ralf Crawford (STScI). Science:
Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)

The researchers also mapped a hot spot in WASP-43b’s atmosphere, and it helped them gauge the exoplanet’s ferocious winds. The hot spot is east of the point receiving the most starlight. That means that powerful winds are moving the heated gas.

The JWST’s spectrum also allowed the researchers to measure the presence of water vapour (H2O) and methane (CH4.) “Webb has given us an opportunity to figure out exactly which molecules we’re seeing and put some limits on the abundances,” said Joanna Barstow, a co-author from the Open University in the U.K.

Webb found water vapour on the dayside and the nightside, indicating cloud thickness and elevation. However, the telescope detected an absence of methane (CH4), which is unusual. The extreme heat on the dayside means carbon is in carbon monoxide (CO) form. But the cooler nightside should contain stable methane. Why isn’t it there? Powerful winds are responsible.

“The fact that we don’t see methane tells us that WASP-43b must have wind speeds reaching something like 5,000 miles per hour,” explained Barstow. “If winds move gas around from the dayside to the nightside and back again fast enough, there isn’t enough time for the expected chemical reactions to produce detectable amounts of methane on the nightside.”

via GIPHY

Previous observations with the Hubble, Spitzer, and others revealed some aspects of WASP-43b’s atmosphere. But the JWST has taken it a step further. By determining the extremely high wind velocity on the exoplanet, scientists now believe the atmosphere is the same all around the planet.

“Taken together, our results highlight the unique capabilities of JWST/MIRI for exoplanet atmosphere characterization,” the authors write in their paper. They point out that there are still some discrepancies between the phase curve, the GCM simulations, and the chemical equilibrium in the atmosphere.

According to the researchers, more JWST exoplanet observations can help resolve them. “These remaining discrepancies underscore the importance of further exploring the effects of clouds and disequilibrium chemistry in numerical models as JWST continues to place unprecedented observational constraints on smaller and cooler planets,” they conclude.

The post Is the JWST Now an Interplanetary Meteorologist? appeared first on Universe Today.

You’ve seen the Sun, but you’ve never seen the Sun like this. This single frame from a video captured by ESA’s Solar Orbiter mission shows the Sun looking very …. fluffy!  You can see feathery, hair-like structures made of plasma following magnetic field lines in the Sun’s lower atmosphere as it transitions into the much hotter outer corona. The video was taken from about a third of the distance between the Earth and the Sun.

See the full video below, which shows unusual features on the Sun, including coronal moss, spicules, and coronal rain.  

Solar Orbiter recorded this video on September 27, 2023 using its Extreme Ultraviolet Imager (EUI) instrument.

ESA said the brightest regions are around one million degrees Celsius, while cooler material looks darker, as it absorbs radiation.

So, just what is coronal moss? It’s what gives the Sun its fluffy appearance here. These peculiar structures on the Sun resemble the moss we find on Earth, in that it appears like fine, lacy features. But on the Sun, they usually can be found around the center of sunspot groups, where magnetic conditions are strong and large coronal loops are forming. The moss is so hot, most instruments can’t detect them. The moss spans two atmospheric layers, the chromosphere and corona.

Features on the Sun’s surface, as seen by Solar Orbiter. Credit: ESA & NASA/Solar Orbiter/EUI Team

Spicules, as their name implies, are tall spires of gas seen on the solar horizon that reach up from the Sun’s chromosphere. These can reach up to a height of 10,000 km (6,000 miles).

At about 0:30 in the video, you’ll see coronal rain. This material is cooler than the rest of the solar surface (probably less than 10,000 °C) versus the one million degrees C of the coronal loops. The rain is made of higher-density clumps of plasma that fall back towards the Sun under the influence of gravity.

Did you see the small eruption in the center of the field of view at about 0:20 seconds in the video? , with cooler material being lifted upwards before mostly falling back down. It’s not small at all — this eruption is bigger than Earth!

Missions like Solar Orbiter, the Parker Solar Probe and the Solar Dynamics Observatory are giving us unprecedented views of the Sun, helping astronomers to learn more about the dynamic ball of gas that powers our entire Solar System.

Further reading: ESA

The post Solar Orbiter Takes a Mind-Boggling Video of the Sun appeared first on Universe Today.

Artificial intelligence and machine learning have become ubiquitous, with applications ranging from data analysis, cybersecurity, pharmaceutical development, music composition, and artistic renderings. In recent years, large language models (LLMs) have also emerged, adding human interaction and writing to the long list of applications. This includes ChatGPT, an LLM that has had a profound impact since it was introduced less than two years ago. This application has sparked considerable debate (and controversy) about AI’s potential uses and implications.

Astronomy has also benefitted immensely, where machine learning is used to sort through massive volumes of data to look for signs of planetary transits, correct for atmospheric interference, and find patterns in the noise. According to an international team of astrophysicists, this may just be the beginning of what AI could do for astronomy. In a recent study, the team fine-tuned a Generative Pre-trained Transformer (GPT) model using observations of astronomical objects. In the process, they successfully demonstrated that GPT models can effectively assist with scientific research.

The study was conducted by the International Center for Relativistic Astrophysics Network (ICRANet), an international consortium made up of researchers from the International Center for Relativistic Astrophysics (ICRA), the National Institute for Astrophysics (INAF), the University of Science and Technology of China, the Chinese Academy of Sciences Institute of High Energy Physics (CAS-IHEP), the University of Padova, the Isfahan University of Technology, and the University of Ferrera. The preprint of their paper, “Test of Fine-Tuning GPT by Astrophysical Data,” recently appeared online.

Illustration of an active quasar. New research shows AI can identify and classify them. Credit: ESO/M. Kornmesser

As mentioned, astronomers rely extensively on machine learning algorithms to sort through the volumes of data obtained by modern telescopes and instruments. This practice began about a decade ago and has since grown by leaps and bounds to the point where AI has been integrated into the entire research process. As ICRA President and the study’s lead author Yu Wang told Universe Today via email:

“Astronomy has always been driven by data and astronomers are some of the first scientists to adopt and employ machine learning. Now, machine learning has been integrated into the entire astronomical research process, from the manufacturing and control of ground-based and space-based telescopes (e.g., optimizing the performance of adaptive optics systems, improving the initiation of specific actions (triggers) of satellites under certain conditions, etc.), to data analysis (e.g., noise reduction, data imputation, classification, simulation, etc.), and the establishment and validation of theoretical models (e.g., testing modified gravity, constraining the equation of state of neutron stars, etc.).”

Data analysis remains the most common among these applications since it is the easiest area where machine learning can be integrated. Traditionally, dozens of researchers and hundreds of citizen scientists would analyze the volumes of data produced by an observation campaign. However, this is not practical in an age where modern telescopes are collecting terabytes of data daily. This includes all-sky surveys like the Very Large Array Sky Survey (VLASS) and the many phases conducted by the Sloan Digital Sky Survey (SDSS).

To date, LLMs have only been applied sporadically to astronomical research, given that they are a relatively recent creation. But according to proponents like Wang, it has had a tremendous societal impact and has a lower-limit potential equivalent to an “Industrial Revolution.” As for the upper limit, Wang predicts that that could range considerably and could perhaps result in humanity’s “enlightenment or destruction.” However, unlike the Industrial Revolution, the pace of change and integration is far more rapid for AI, raising questions about how far its adoption will go.

The Sloan Digital Sky Survey telescope stands out against the breathtaking backdrop of the Sacramento Mountains. Credit: SDSS/Fermilab Visual Media Services

To determine its potential for the field of astronomy, said Wang, he and his colleagues adopted a pre-trained GPT model and fine-tuned it to identify astronomical phenomena:

“OpenAI provides pre-trained models, and what we did is fine-tuning, which involves altering some parameters based on the original model, allowing it to recognize astronomical data and calculate results from this data. This is somewhat like OpenAI providing us with an undergraduate student, whom we then trained to become a graduate student in astronomy. 

“We provided limited data with modest resolution and trained the GPT fewer times compared to normal models. Nevertheless, the outcomes are impressive, achieving an accuracy of about 90%. This high level of accuracy is attributable to the robust foundation of the GPT, which already understands data processing and possesses logical inference capabilities, as well as communication skills.”

To fine-tune their model, the team introduced observations of various astronomical phenomena derived from various catalogs. This included 2000 samples of quasars, galaxies, stars, and broad absorption line (BAL) quasars from the SDSS (500 each). They also integrated observations of short and long gamma-ray bursts (GRBs), galaxies, stars, and black hole simulations. When tested, their model successfully classified different phenomena, distinguished between types of quasars, inferred their distance based on redshift, and measured the spin and inclination of black holes.

“This work at least demonstrates that LLMs are capable of processing astronomical data,” said Wang. “Moreover, the ability of a model to handle various types of astronomical data is a capability not possessed by other specialized models. We hope that LLMs can integrate various kinds of data and then identify common underlying principles to help us understand the world. Of course, this is a challenging task and not one that astronomers can accomplish alone.”

The Vera Rubin Observatory at twilight on April 2021. It’s been a long wait, but the observatory should see first light later this year. Credit: Rubin Obs/NSF/AURA

Of course, the team acknowledges that the dataset they experimented with was very small compared to the data output of modern observatories. This is particularly true of next-generation facilities like the Vera C. Rubin Observatory, which recently received its LSST camera, the largest digital camera in the world! Once Rubin is operational, it will conduct the ten-year Legacy Survey of Space and Time (LSST), which is expected to yield 15 terabytes of data per night! Satisfying the demands of future campaigns, says Wang, will require improvements and collaboration between observatories and professional AI companies.

Nevertheless, it’s a foregone conclusion that there will be more LLM applications for astronomy in the near future. Not only is this a likely development, but a necessary one considering the sheer volumes of data astronomical studies are generating today. And since this is likely to increase exponentially in the near future, AI will likely become indispensable to the field of study.

Further Reading: arXiv

The post What Can AI Learn About the Universe? appeared first on Universe Today.

The Search for Life in our Solar System leads seekers to strange places. From our Earthbound viewpoint, an ice-covered moon orbiting a gas giant far from the Sun can seem like a strange place to search for life. But underneath all that ice sits a vast ocean. Despite the huge distance between the moon and the Sun and despite the thick ice cap, the water is warm.

Of course, we’re talking about Enceladus, and its warm, salty ocean—so similar to Earth’s in some respects—takes some of the strangeness away.

Enceladus is Saturn’s sixth-largest moon, and the Cassini spacecraft observed it during its mission to the Saturn system. Scientists discovered that plumes of water originating from Enceladus’ southern region are responsible for one of Saturn’s rings. They also discovered that the water is salty. Any place we find warm, salty water attracts our immediate attention, even when it’s covered by kilometres of ice and is 1.5 billion kilometres away from the life-giving Sun.

There’s lots of talk about a future mission to Enceladus to explore the moon and its potentially life-supporting ocean in more detail. But until then, scientists are working with their current data, and using models and simulations to understand the moon better.

Enceladus’ most defining surface features are its Tiger Stripes. They’re four parallel, linear depressions on the moon’s surface about 130 km long, 2 km wide, and 500 meters deep. They have higher temperatures than their surroundings, indicating that cryovolcanism is active. The stripes are the source of Enceladus’ plumes.

Geysers erupt from Enceladus’ Tiger Stripes in this image from the Cassini spacecraft. Image Credit: By NASA/JPL/SSI – http://www.nasa.gov/mission_pages/cassini/multimedia/pia11688.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=15592605

New research suggests that strike-slip faults at the moon’s prominent Tiger Stripe features allow plumes of water from Enceladus to escape into space. It’s published in Nature Geoscience and titled “Jet activity on Enceladus linked to tidally driven strike-slip motion along tiger stripes.” The lead author is Alexander Berne, a doctoral candidate in Geophysics at the California Institute of Technology.

The plumes above the Tiger Stripes aren’t stable and continuous. They wax and wane as the moon follows its 33-hour orbit around Saturn. Tidal heating keeps the moon’s water in liquid form, and according to the researchers, the same tidal forces are responsible for the intermittent plumes. Theory shows that tidal forces open and close faults at the Tiger Stripes like an elevator door, and that turns the plumes on and off.

However, those theories can’t accurately predict the timing of the plumes’ peak brightness. They also show that tidal forcing alone doesn’t provide enough energy to open and close the faults.

This research digs deeper into the question and provides an answer. The authors say that rather than acting like an elevator door, strike-slip faults at the Tiger Stripes open and close to regulate plume activity. This is similar to what happens on Earth in places like the San Andreas Fault. It’s a strike-slip fault where one side shears past the other, causing Earthquakes. The critical part of this is that strike-slip faults require less energy than the elevator opening and closing scenario.

Models are more effective as they’re fed more detailed and accurate data. Berne and his co-researchers built a numerical model that simulates the strike-skip faults on Enceladus. They included friction, compressional forces and shear forces. The numerical model showed the faults acting in concert with the changing plumes. This strongly suggests that Enceladus’ orbit and the tidal forces acting on the moon cause the strike-slip faults to open and close.

This illustration from the research explains how strike-slip faults are responsible for the plumes erupting from Enceladus’ Tiger Stripes. As the moon orbits Saturn, tidal forces open and close the faults. Image Credit: Berne et al. 2024.

The Tiger Stripes have bent sections that pull apart under strain. Since they’re bent, an opening appears as they slide. The plumes come from these openings.

The research team’s work and previous research into the Tiger Stripes by NASA’s Jet Propulsion Laboratory both support the idea that the plumes come from these strike-slip faults.

“We now appear to have both geologic and geophysical reasons to suspect that jet activity occurs at pull-aparts along Enceladus’s tiger stripes,” said lead author Berne.

This figure from the research shows the degree of displacement and slip at the Tiger Stripe faults at two different points in Enceladus’ orbit. Image Credit: Berne et al. 2024.

Enceladus gets most of its attention because of its potential to support life. The plumes themselves aren’t part of what life needs, but they’re a window into the moon’s potential habitability.

“For life to evolve, the conditions for habitability have to be right for a long time, not just an instant,” said study co-author Mark Simons, Professor of Geophysics at Caltech. “On Enceladus, you need a long-lived ocean. Geophysical and geological observations can provide key constraints on the dynamics of the core and the crust as well as the extent to which these processes have been active over time.”

There’s a lot more work to be done to understand Enceladus. On Earth, satellites can monitor the movement at strike-slip faults and use it to better understand Earthquakes. Once we get a spacecraft to Enceladus, it could do the same.

“Detailed measurements of motion along the tiger stripes are needed to confirm the hypotheses laid out in our work,” Berne says. “For instance, we now have the capacity to image fault slip, such as earthquakes, on Earth using radar measurements from satellites in orbit. Applying these methods at Enceladus should allow us to better understand the transport of material from the ocean to the surface, the thickness of the ice crust, and the long-term conditions which may enable life to form and evolve on Enceladus.”

When we get a spacecraft to Enceladus, it can monitor the faults and jets over multiple orbits. That will allow researchers to test their predictions.

“These observations could provide key constraints on the mechanical nature of the crust, tidal controls on jet activity and the evolution of the south polar terrain,” the authors conclude.

The post Enceladus’s Fault Lines are Responsible for its Plumes appeared first on Universe Today.

Few things in life are certain. But it seems highly probable that people will explore the lunar surface over the next decade or so, staying there for weeks, perhaps months, at a time. That fact bumps up against something we are certain about. When human beings spend time in low-gravity environments, it takes a toll on their bodies.

What can be done?

Scientists have studied the effects of microgravity and low gravity on the human body. Several problems crop up, like muscle atrophy and bone demineralization. Cardiovascular conditioning suffers, as does neural control of body posture and movement. But while researchers are learning more and more about the effects, solutions are lagging behind.

A new paper published in Royal Society Open Science suggests a novel, low-tech solution for these problems. Its title is “Horizontal running inside circular walls of Moon settlements: a comprehensive countermeasure for low-gravity deconditioning?” The lead author is Alberto Minetti, a Physiology Professor at the University of Milan.

Minetti and his co-authors point out that specific exercises for specific problems may not be the best approach. Instead, whole-body exercise could be a powerful tool for supporting astronaut health. “Rather than training selected muscle groups only, ‘whole-body’ activities such as locomotion seem better candidates,” they explain. However, there’s a problem with that. “But at Moon gravity, both ‘pendular’ walking and bouncing gaits like running exhibit abnormal dynamics at faster speeds,” they write.

The abnormal dynamics mean that astronauts don’t benefit much from that type of exercise. It’s hindered by an ” … imbalance between the kinetic and potential energy of the body centre of mass,” the authors write. That means it can’t be used to get the same kind of exercise it would provide on the Earth. “Additionally, the metabolic demands of bouncing gaits are reduced at Moon gravity, limiting their potential stimulus for cardiorespiratory fitness,” the authors explain.

There are some potential solutions out there to help lunar astronauts maintain their health in low gravity. One is a centrifuge, where the rotating motion simulates gravity, encouraging the body to maintain muscle and bone mass. But they’re energy-intensive and impractical.

The authors are proposing a novel solution. Have you ever seen a Wall of Death?

A stuntman riding on a Wall of Death. Friction and centripetal force allow him to ride on the wall’s vertical surface. Image Credit: By SeaDave from Fairlie, Scotland – Owner of the Wall of Death, in his family for 80 years.Uploaded by MaybeMaybeMaybe, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=22817835

“Here, we propose a novel solution: lunar inhabitants could engage in running on the inside of vertical circular walls, hence running parallel to the Moon’s surface,” the authors write. Exercising in a Wall of Death (WoD) would help maintain muscle mass, bone density, cardiovascular fitness, and neural control.

On Earth, the gravity is too strong for humans to run around the sides of a WoD. Only motorized vehicles and bicycles can do it. But on the Moon, the weaker gravity makes them practical.

The researchers simulated a lunar WoD and tested the performance of subjects running in it. They hired a WoD for one day and used a harness of bungee cords to reduce participants’ body weight, simulating the Moon’s lower gravity.

The researchers removed the roof from the WoD and used a crane to support the harness. The middle inset image is unrelated to the research and illustrates the peculiar upward leaning posture of someone in the WoD. Image Credit: Minetti et al. 2024.

Two participants took part in the tests: a 36-year-old man and a 33-year-old woman. The bungees were tuned so each participant weighed one-sixth of their body weight. The harness unloaded one side of the subjects’ bodies to further mimic lunar conditions. Each participant’s data from the WoD was combined with treadmill data to give robust results.

Once inside the WoD and connected to the harness, this is what the experiment looked like.

In this image, the 33-year-old female subject is connected to the harness and running around the inside of the Wall of Death. Image Credit: Minetti et al. 2024.

The participants quickly got the hang of the unusual motion required to run horizontally inside the WoD. “This process required only 5–8 attempts and allowed them to start running with no assistance,” the authors write. The participants “… ended their performance by safely slowing down their pace and descending from the horizontal posture on the wall down to the upright one on the WoD floor, with no injuries,” they explained.

via GIPHY

The authors say they’ve successfully demonstrated the basics of using a WoD to support lunar astronaut health. “We have demonstrated for the first time that humans can safely run horizontally in low gravity conditions inside a cylinder, sized as a terrestrial ‘WoD’, through a speed-driven, self-generated higher artificial gravity,” they explain.

The researchers are confident that the Wall of Death idea can help lunar astronauts deal with the chronic effects of lunar gravity. At the same time, they’re cognizant of their small sample size and the study’s other limitations.

“In conclusion, while being aware of the small sample size, of the crudeness of kinematics acquisition in such a peculiar field experiment, and that dedicated bed rest studies will be needed to refine this topic, we are confident in our findings,” they write in their conclusion.

Though normal running on the Moon is impossible, the WoD provides a way to gain the benefits of running in short WoD exercise sessions daily. Participants using the WoD created “… a sufficiently high (lateral) self-generated artificial gravity likely capable of maintaining, through a few short, almost ‘terrestrial’ running laps a day, an acceptable cardio-motor fitness and bone mineral status, useful to locally move and work around, to prepare the long trip to Mars, and to return home in good condition.”

There’s an elegance around low-tech solutions to confounding problems. A simple WoD could be the solution to the Moon’s low gravity instead of a complicated, energy-hungry device like a centrifuge.

“All of this, by using an inexpensive and passive facility already built in their circular inhabited units,” the authors conclude.

The post Lunar Explorers Could Run to Create Artificial Gravity for Themselves appeared first on Universe Today.

Space debris is a growing problem, so companies are working on ways to mitigate it. A new satellite called ADRAS-J was built and launched to demonstrate how a spacecraft could rendezvous with a piece of space junk, paving the path for future removal. Astroscale Japan Inc, the Japanese company behind the satellite, released a new picture from the mission showing a close image of its target space debris, a discarded Japanese H2A rocket’s upper stage, captured from just a few hundred meters away.

ADRAS-J stands for Active Debris Removal by Astroscale-Japan, and is the first satellite ever to attempt to safely approach, characterize and survey the state of an existing piece of large debris. This mission will only demonstrate Rendezvous and Proximity Operations (RPO) capabilities by operating in near proximity to the piece of space debris, and gather images to assess the rocket body’s movement and the condition of the structure, Astroscale Japan said.

ADRAS-J Launch. Credit: Astroscale Japan, Inc.

The mission launched from New Zealand on February 18 and is part of Phase 1 of the Japan Aerospace Exploration Agency’s plan to deal with space debris. Shortly after launch, the ADRAS-J spacecraft began its maneuvers to rendezvous with the chosen piece of space debris. On April 9, mission engineers maneuvered the spacecraft to a desired position several hundred kilometers away from the rocket stage. Then, by April 16, the spacecraft was able to match the orbit of the rocket stage. By the next day, using  navigation inputs from the spacecraft’s suite of rendezvous payload sensors, ADRAS-J was able to attain close approach of several hundred meters.  

“The unprecedented image marks a crucial step towards understanding and addressing the challenges posed by space debris, driving progress toward a safer and more sustainable space environment,” Astroscale Japan said in a press release.

This particular rocket stage was chosen because it did not have any GPS data. Instead, the operations team had to rely on ground based observational data to approximate its position to make the approach. This provided a realistic target for testing debris analysis activity.

The next task, ADRAS-J will attempt to capture additional images of the upper stage through various controlled close approach operations. Astroscale Japan said the images and data collected are expected to be crucial in better understanding the debris and providing critical information for future removal efforts.

A future mission, ADRAS-J2, will also attempt to safely approach the same rocket body through RPO, obtain more images, then remove and deorbit the rocket body using in-house robotic arm technologies.

The post This is an Actual Picture of Space Debris appeared first on Universe Today.

Few space images are as iconic as those of the Horsehead Nebula. Its shape makes it instantly recognizable. Over the decades, a number of telescopes have captured its image, turning it into a sort of test case for a telescope’s power.

The JWST has them all beat.

The Horsehead Nebula is about 1300 light-years away in Orion. It’s part of the much larger Orion Molecular Cloud Complex. Horsehead is visible near the three stars in Orion’s Belt in a zoomed-in image.

The Horsehead Nebula is visible in this image of Orion’s Belt. It’s in the lower left, extending horizontally, to the lower left of the belt star Alnitak. Image Credit: By Davide De Martin (http://www.skyfactory.org); Credit: Digitized Sky Survey, ESA/ESO/NASA FITS Liberator – https://www.spacetelescope.org/projects/fits_liberator/fitsimages/davidedemartin_12/ (direct link), Public Domain, https://commons.wikimedia.org/w/index.php?curid=1329999

The leading image shows JWST’s view of the Horsehead Nebula alongside two other views. The Euclid image was captured in November 2023. Euclid features a wide-angle, 600-megapixel camera, and its primary job is to measure the redshift of galaxies and the Universe’s expansion due to dark energy. It took Euclid about one hour to capture the image, showcasing the telescope’s ability to gather highly detailed images quickly.

The Hubble captured its image in 2013 and was released as the telescope’s 23rd-anniversary featured image. The venerable Hubble does a good job of revealing structures hidden by dust. There’s nothing left to say about the Hubble that hasn’t been said already. It’s the revered elder among telescopes, and if you feel no reverence towards it, its contribution to science, and the people responsible for it, you may have a bad case of ennui.

The third image is a new one from the JWST’s NIRCam instrument. It’s described as the sharpest image of the Horsehead ever taken. It shows a small part of the iconic nebula in detail we don’t usually see. The JWST is so powerful it even shows background galaxies.

A zoom-in of the JWST image. The detail is incredible. Image Credit: ESA/Webb, CSA, K. Misselt, M. Zamani (ESA/Webb)

The Horsehead Nebula is the result of stellar erosion. The nebula itself was formed by a collapsing cloud of material, and a nearby hot star called Sigma Orionis illuminates the structure. The nebula is denser than its surrounding gas and has resisted the dissipative energy of the star, while the gas that used to surround it is long gone.

This definitely isn’t the last we’ll see of Horsehead. New, powerful telescopes coming online soon, like the Giant Magellan Telescope and the European Extremely Large Telescope will likely take a crack at the nebula. Prepare to be wowed.

There’s no rush. According to astronomers, the Horsehead Nebula will eventually be eroded away, too, but not for another five million years or so.

The post Insanely Detailed Webb Image of the Horsehead Nebula appeared first on Universe Today.