All's not as it appears, this tale has many twists -
but if I wasn't here documenting the story
would that mean that the plot did not exist?

— Peter Hammill

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Updated: 20 hours 17 min ago

Io Has Been Volcanically Active for its Entire History

Thu, 05/30/2024 - 11:04pm

Jupiter’s moon Io is a volcanic powerhouse. It’s the most geologically active world in the Solar System, sporting more than 400 spouting volcanoes and vents on its surface. Has it always been this way? A team of planetary scientists says yes, and they have the chemical receipts to prove it.

In a recent paper, the team headed by CalTech scientist Katherine de Kleer cites data from millimeter observations of elemental isotopes found in Io’s eruptions. They found that chemicals like chlorine and sulfur exist in higher quantities at Io than in comparable places in the Solar System. Analysis shows that Io hasn’t just started erupting lately—it’s been going on for most of its history. And, it’s so volcanic that it practically resurfaces itself every million years or so.

The discovery of volcanism on Io was one of the major results of the Voyager mission. As the two spacecraft swept past Jupiter in 1979, their images revealed Io’s volcanic features and plumes. Since that time, the Galileo, Cassini-Huygens, New Horizons, and Juno missions also sent images. The Jovian system and its moons are also frequent targets for ground- and space-based observatories, including Hubble Space Telescope and JWST.

Facts about Io

Io is the fourth-largest Jovian moon and is one of the four Galilean satellites. It orbits closest to Jupiter and gets pulled by a gravitational tug-of-war between Jupiter and the other Galilean moons. The result is a process called “tidal heating” deep inside Io, produced by friction. That generates heat, which melts Io’s interior, and opens up vents so that the heat and melted material can escape to the surface.

An artist’s concept of the interior of Io. By Kelvinsong – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31526383

This little moon is mostly silicate rock atop an iron or iron sulfide core. The surface is scarred with volcanoes and deformed by compressional forces beneath the crust. The most obvious features are the volcanic mountains, plumes, and lava flows. Currently, Io’s volcanoes resurface the landscape at a rate of about 0.1 to 1.0 cm per year. They also paint its surface in an amazing array of colors. During the Voyager 2 flyby, people often compared its appearance to a pizza. The colors come mainly from sulfur and sulfurous compounds deposited across the landscape.

Normally, geologists would look at its surface and count craters to get an idea of its age. But, since volcanic flows erase craters, there’s no easy visual way to determine how long volcanic features have been around. However, it turns out that abundances of certain isotopes of sulfur and other elements could provide a good record the history of volcanism on Io.

Analyzing Io’s Chemistry

Io has probably lost mass to space throughout its history. de Kleer and her colleagues point out that its supply of volatile elements should be highly enriched in heavy stable isotopes. That’s because atmospheric escape processes generally favor the loss of lighter isotopes. They suggest that stable isotope measurements of volatile elements, such as sulfur and chlorine, could give accurate details about the history of volcanism at Io. So, it makes sense, then, to do a thorough chemical analysis of Io’s volcanic emissions now and extrapolate back.

Understanding Io’s current chemistry, requires, among other things, a good idea of its mass-loss history. Io’s mass loss occurs because of collisions between atmospheric molecules and energetic particles trapped in Jupiter’s magnetosphere. If this continued over Io’s history, then its chemistry should provide evidence of the volcanic past. In their paper, the team discusses the assumptions they made, including estimates of Io’s initial inventory of sulfur, as well as possible early mass-loss rates that could affect its current abundances of sulfur and chlorine—two elements that help determine past and present volcanism.

To get that history, team used the Atacama Large Millimeter Array to observe gases in Io’s atmosphere. The goal was to measure SO2, SO, NaCl, and KCl in various forms and determine the ratios of 34S to 32S and 37Cl to 35Cl. After analyzing the data, the team found that Io has lost at least 94 to 99 percent of its available sulfur over time. In addition, the measurements show enriched levels of chlorine. This probably indicates that Io has been volcanically active throughout time. It’s also possible that this tiny moon has experienced higher rates of outgassing and mass loss early in its history. More measurements should help scientists constrain Io’s volcanic activity even more tightly.

For More Information

Isotopic Evidence of Long-lived Volcanism on Io
Violent Volcanoes Have Wracked Jupiter’s Moon Io for Billions of Years

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Categories: Astronomy

Webb Finds the Farthest Galaxy Ever Seen (So Far)

Thu, 05/30/2024 - 9:02pm

There are some things that never cease to amaze me and the discovery of distant objects is one of them. The James Webb Space Telescope has just found the most distant galaxy ever observed! It has the catchy title JADES-GS-z14-0 and it has a redshift of 14.32. This means its light left when the Universe was only 290 million years old! That means the light left the source LOOOONG before even our Milky Way was here! How amazing is that!

The James Webb Space Telescope (JWST) with its 6.5m mirror was launched on 25 December 2021 and has quickly proven itself to be the most powerful space telescope ever built. It was designed to explore the Universe in visible and infrared radiation so that it could probe straight through dust to reveal hidden details behind. It is positioned at the second Lagrange point where the gravity of the Earth is balanced by the gravity of the Sun and it maintains a stable 1.5 million km from Earth. 

Artist impression of the James Webb Space Telescope

Over the last couple of years, astronomers have been using JWST to study the Cosmic Dawn! This period of time existed just a few hundred million years after the big bang but studying galaxies so far back in time required the sensitivity of the JWST. They provide valuable information about the gas and stars within and help to understand their formation. 

An international team were using JWST data that had been collected as part of the Advanced Deep Extragalactic Survey (JADES) using the Near-Infrared Spectrograph known as NIRSpec. They were able to acquire a spectrum of the galaxy revealing a redshift of 14.32. The redshift phenomenon occurs when the light from distant objects in space shift toward the red end of the spectrum. It was originally thought this was due to the movement but instead it is caused by the expansion of space. The greater the redshift, the faster the object is moving away and therefore the further away it is. 

The redshift of JADES-GS-z14-0 makes it the most distant galaxy known and it corresponds to the light having been emitted at a time when the Universe was just under 300 million years old. The team estimate the galaxy to be just over 1,600 light years across, that’s in comparison to the Milky Way which is thought to be 100,000 light years across. It is fairly typical of distant, early galaxies to be bright due to gas falling into a supermassive black hole but in the case of JADES-GS-z14-0 the light seems to be created by hot young stars. 

The image that has been released shows a field of thousands of distant galaxies of all manner of shapes, colours and sizes. One solitary bright star is visible in the foreground with the trademark diffraction spikes caused by the JWST optics. A box just to the lower right of centre highlights the location with the zoomed in image of the galaxy superimposed. The galaxy looks very different from those we tend to see in today’s Universe as it appears far less structured. 

Source : Webb finds most distant known galaxy

The post Webb Finds the Farthest Galaxy Ever Seen (So Far) appeared first on Universe Today.

Categories: Astronomy

Pluto Has an Ocean of Liquid Water Surrounded by a 40-80 km Ice Shell

Thu, 05/30/2024 - 2:57pm

On July 14th, 2015, the New Horizons spacecraft conducted the first-ever flyby of Pluto, which once was (and to many, still is) the ninth planet of the Solar System. While the encounter was brief, the stunning images and volumes of data it obtained revealed a stunningly vibrant and dynamic world. In addition to Pluto’s heart, floating ice hills, nitrogen icebergs, and nitrogen winds, the New Horizons data also hinted at the existence of an ocean beneath Pluto’s icy crust. This effectively made Pluto (and its largest moon, Charon) members of the “Ocean Worlds” club.

Almost a decade after that historic encounter, scientists are still making discoveries from New Horizons data. In a new paper, planetary scientists Alex Nguyen and Dr. Patrick McGovern used mathematical models and images to learn more about the possible ocean between Pluto’s icy surface and its silicate and metallic core. According to their analysis, they determined that Pluto’s ocean is located beneath a surface shell measuring 40 to 80 km (25 to 50 mi), an insulating layer thick enough to ensure that an interior ocean remains liquid.

Nguyen is a graduate student in Earth, environmental, and planetary sciences in Arts & Sciences at Washington University in St. Louis (WUSTL), while Dr. McGovern is a Senior Staff Scientist with the Lunar and Planetary Institute (LPI) in Houston. Their paper, “The role of Pluto’s ocean’s salinity in supporting nitrogen ice loads within the Sputnik Planitia basin,” recently appeared in the journal Icarus. The study is part of Nguyen’s Ph.D. research at Washington University, where he is an Olin Chancellor’s Fellow and a National Science Foundation Graduate Research Fellow.

This cutaway image of Pluto shows a section through the area of Sputnik Planitia, with dark blue representing a subsurface ocean and light blue for the frozen crust. Artwork by Pam Engebretson, courtesy of UC Santa Cruz.

For decades, planetary scientists assumed Pluto was far too cold to support an interior ocean. Pluto orbits well beyond the Solar System’s “Frost Line,” the boundary beyond which volatile elements (water, carbon dioxide, ammonia, etc.) become solid. With an average surface temperature of -229 °C (-380°F), even nitrogen and methane become as solid as rock. As Nguyen indicated in a recent interview with The Source (WUSTL’s news site), “Pluto is a small body. It should have lost almost all of its heat shortly after it was formed, so basic calculations would suggest that it’s frozen solid to its core.”

But thanks to New Horizons, scientists were presented with multiple lines of evidence that suggest Pluto likely has an interior ocean. This includes cryovolcanoes, such as those observed on Ceres, Europa, Ganymede, Enceladus, Titan, Triton, and other “Ocean Worlds.” While the existence of this ocean is still subject to debate, the theory is gaining acceptance to the point that it is considered a very real possibility. For their study, Nguyen and McGovern created mathematical models to explain the cracks and bulges in the ice covering Pluto’s Sputnik Planitia Basin.

Their results indicate that an ocean could exist beneath an icy shell 40 to 80 km (25 to 50 mi) thick, which would be sufficient to ensure that Pluto could maintain a liquid water ocean in its interior despite surface conditions. They also calculated the likely density or salinity of the ocean based on the surface features and determined that Pluto’s ocean could be up to 8% denser than Earth’s oceans. This salinity level would make Pluto’s ocean comparable to the Great Salt Lake, the Dead Sea, and other high-salinity bodies of water on Earth.

According to Nguyen, any variations in this density (greater or lower) would be evident from the cracks and fractures in the Sputnik Platina Basin. “We estimated a sort of Goldilocks zone where the density and shell thickness is just right,” he said. If the ocean were less dense, the ice shell would collapse, leading to many more fractures in the surface. If it were denser, the ice sheet would be more buoyed, which would be evident from there being fewer fractures. Unfortunately, it could be many decades before another spacecraft reaches Pluto to help confirm these findings. In the meantime, the case for Pluto’s interior ocean grows stronger!

Further Reading: Washington University at St. Louis, Icarus

The post Pluto Has an Ocean of Liquid Water Surrounded by a 40-80 km Ice Shell appeared first on Universe Today.

Categories: Astronomy

Where are All the Primordial Black Holes?

Thu, 05/30/2024 - 2:37pm

The earliest black holes in the Universe called primordial black holes (PBHs), are strong contenders to help explain why the Universe is heavier than it looks. There’s only one problem: these miniature monsters haven’t exactly been observed—yet. But, when astronomers do find them, they might turn out to be part of the Universe’s dark matter component.

Primordial black holes are one of several types of highly massive objects thought to exist in the Universe. We already know about stellar-mass black holes. They form during the deaths of hugely massive stars and generally end up containing up to dozens of solar masses. Then there are the supermassive black holes, embedded in the hearts of most galaxies. They sequester up to millions of solar masses.

The intermediate-mass black holes occupy the middle of the “black hole” spectrum. They’re another hot topic in black hole research circles. Appropriately enough, the masses of these black holes are between their stellar and supermassive counterparts. All these types of massive objects can collide with each other to grow bigger black holes. That generates gravitational waves that can be detected. The “ping” of each gravitational wave tells scientists a great deal about the objects colliding, including their masses.

How we might discover primordial black holes and help solve the dark matter mystery. Credit: ESA Understanding Primordial Black Holes in Context of Cosmic History

While astronomers search for PHBs, others are looking to explain why they might be part of the dark matter component of the Universe. In addition, they could explain the origin of binary black holes detected in gravitational wave observations.

A team of researchers at the University of Tokyo examined the “problem” of PBHs. Their work suggests that there should be far fewer of these objects than current models show. But, nobody knows how many existed back then. So, astronomers search them out using gravitational wave observatories. Their discovery should open a window on conditions in the early Universe when PBH formed.

These miniature ones are fascinating to think about. “Many researchers feel they are a strong candidate for dark matter, but there would need to be plenty of them to satisfy that theory,” said graduate student and team member Jason Kristiano. “They are interesting for other reasons too, as since the recent innovation of gravitational wave astronomy, there have been discoveries of binary black hole mergers, which can be explained if PBHs exist in large numbers. But despite these strong reasons for their expected abundance, we have not seen any directly, and now we have a model which should explain why this is the case.”

Modeling the Existence of Primordial Black Holes

The big question about PHBs: do (or did) they exist? And, can they be part of the dark matter component of the Universe? To answer that, Kristiano and his advisor Jun’ichi Yokoyama, searched through models of PBH formation. The best ones do not agree with the observed conditions of the leftover light fingerprint of the Big Bang. That’s called the cosmic microwave background (CMB). This is important, since PBHs formed in very early epochs of cosmic history, soon after the Big Bang. So, the team used the best model of PBH formation and applied quantum field theory to bring the model into alignment with reality.

Yokoyama explained the background behind their work. “At the beginning, the universe was incredibly small, much smaller than the size of a single atom. Cosmic inflation rapidly expanded that by 25 orders of magnitude. At that time, waves traveling through this tiny space could have had relatively large amplitudes but very short wavelengths. What we have found is that these tiny but strong waves can translate to otherwise inexplicable amplification of much longer waves we see in the present CMB,” said Yokoyama.

“We believe this is due to occasional instances of coherence between these early short waves, which can be explained using quantum field theory, the most robust theory we have to describe everyday phenomena such as photons or electrons. While individual short waves would be relatively powerless, coherent groups would have the power to reshape waves much larger than themselves. This is a rare instance of where a theory of something at one extreme scale seems to explain something at the opposite end of the scale.”

From Fluctuations to Miniature Black Holes

Those early small-scale fluctuations Yokohama describes affect some of the larger-scale fluctuations in the cosmic microwave background. Researchers can use measurements of wavelengths in the CMB to constrain the extent of corresponding wavelengths in the early Universe. That also puts some limits on any other phenomena that rely on the shorter, stronger wavelengths. And this is where the PBHs come back in.

“It is widely believed that the collapse of short but strong wavelengths in the early universe is what creates primordial black holes,” said Kristiano. “Our study suggests there should be far fewer PBHs than would be needed if they are indeed a strong candidate for dark matter or gravitational wave events.”

The next step relies on gravitational wave observatories and other types of observations. LIGO in the U.S., Virgo in Italy and KAGRA in Japan, are cooperating in observations aimed at finding the first PHBs. The results should help refine the ideas from Yokoyama’s team about PHBs and dark matter.

For More Information

The Case of the Missing Black Holes
Constraining Primordial Black Hole Formation from Single-Field Inflation
Note on the Bispectrum and One-loop corrections in Single-field Inflation with Primordial Black Hole Formation

The post Where are All the Primordial Black Holes? appeared first on Universe Today.

Categories: Astronomy

A New Telescope Can Observe Even in Broad Daylight

Thu, 05/30/2024 - 11:51am

Astronomy is a profession that, so far, has only been done at night, at least on Earth. Light from the Sun overwhelms any light from other stars, making it impractical for both professional and amateur astronomers to look at the stars during daytime. There are several disadvantages to this, not the least of which is that many potentially exciting parts of the sky aren’t visible at all for large chunks of the year as they pass too close to the Sun. To solve this, a team from Macquarie University, led by graduate student Sarah Caddy, developed a multi-camera system for a local telescope that allows them to observe during daytime.

The University has a system known as the Huntsman Telescope, named after the famous Australian spider species. Its design was inspired by the Dragonfly Telescope Array, initially designed by researchers at the University of Toronto and Yale, among other institutions. Both telescopes feature an array of 10 telephoto lenses from Canon, the camera manufacturer, arranged in a honeycomb pattern.

Typically, the telescope is used for nighttime astronomy at the Siding Spring Observatory, about a seven-hour drive from Sydney. However, Ms. Caddy thought it could do better and potentially continue observations during the day.

An image of Betelgeuse during the day using the Huntsman Telescope.
Credit – Macquarie University

They originally tested their ideas, which focused on a number of broadband filters and a single-lens test version of the Huntsman telescope. This allowed them to optimize things like exposure times and timing and show a proof of concept that they then wrote up in a paper in the Publications of the Astronomical Society of Australia. 

In particular, Ms. Caddy and her colleagues are excited about several use cases. One is tracking particular stars that might soon undergo an exciting event. Betelgeuse comes to mind, as astronomers expect it to undergo a supernova sometime “soon,” though soon in astronomical terms could mean anywhere between tomorrow and 10 million years from now. If Betelgeuse happens to be on the other side of the Sun when it goes supernova, without daylight astronomy, there would be months of a gap where we would miss out on collecting data on the supernova that happened nearest to us in recorded history, and astronomers everywhere would be frustrated.

This is exactly why the Huntsman team used a daytime image of Betelgeuse as part of their proof of concept. While it might not look like a typical image of the star that is 650 light years away, the fact that it is visible at all during the daytime is striking.

Betelgeuse is one of the most interesting stars in the sky – a potential supernova that goes through occasional dimming periods, as Fraser explains.

Another use case is the tracking of satellites. As the orbital space around Earth becomes increasingly crowded, there’s a higher likelihood that satellites will begin colliding, which could eventually result in something as severe as Kessler syndrome, which we’ve discussed before here at UT. Unfortunately, astronomers can only track satellites during the night, so if one of their orbits happens to shift for some reason during a day cycle, it would be impossible for them to suggest changes to the orbital paths of other satellites that are close by.

Unless you have daytime astronomy, which allows you to track satellites during the day, there’s a significantly decreased risk of two running into each other unexpectedly. This data can be combined with radar readings to help avoid catastrophic collisions, no matter how crowded orbital space gets.

This proof of concept is a step toward making those observations a reality. As it is more fully tested, the southern sky will become much more accessible, and it could pave the way for other daytime astronomy projects in other parts of the world.

Learn More:
Macquarie University – Stargazing in broad daylight: How a multi-lens telescope is changing astronomy
Caddy, Spitler & Ellis – An Optical Daytime Astronomy Pathfinder for the Huntsman Telescope
UT – Astro-Challenge: Adventures in Daytime Astronomy
UT – Why Can We See the Moon During the Day?

Lead Image:
Macquarie’s Huntsman Telescope can potentially observe space during the day.
Credit – Macquarie University

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Categories: Astronomy

Next-Generation Radar Will Map Threatening Asteroids

Thu, 05/30/2024 - 9:21am

When the Arecibo Observatory dish in Puerto Rico collapsed in 2020, astronomers lost a powerful radio telescope and a unique radar instrument to map the surfaces of asteroids and other planetary bodies. Fortunately, a new, next-generation radar system called ngRADAR is under development, to eventually be installed at the 100-meter (328 ft.) Green Bank Telescope (GBT) in West Virginia. It will be able to track and map asteroids, with the ability to observe 85% of the celestial sphere. It will also be able to study comets, moons and planets in our Solar System.

“Right now, there is only one facility that can conduct high-power planetary radar, the 70-meter (230-foot) Goldstone antenna that is part of NASA’s Deep Space network,” said Patrick Taylor, the project director for ngRADAR and the radar division head for the National Radio Astronomy Observatory. “We had begun this process of developing a next generation radar system several years ago, but with the loss of Arecibo, this becomes even more important.”

The iconic Arecibo Radio Telescope, before its collapse in 2020: Credit: UCF

Planetary radar can reveal incredibly detailed information about the surfaces and makeup of asteroids, comets, planets, and moons. The ngRADAR system could provide unprecedented data on these objects. In fact, a recent test with a low-power prototype of ngRADAR at the GBT produced some of the highest resolution planetary radar images ever captured from Earth. But the hallmark of the new system will be seeking out near Earth asteroids and comets to evaluate any hazard they might present to our planet. 

“Radar is really powerful in determining the orbits of these asteroids and comets,” Taylor told Universe Today in an interview, “and the new system will deliver very precise data that will allow us to predict where these small bodies will be in the future. That will be one of the highest priority uses for the next generation radar system, where we can track and characterize near-Earth asteroids and comets to evaluate any hazard they might present to Earth in the future.”

A Radar Flashlight

Usually, radio telescopes collect weak light in the form of radio waves from distant stars, galaxies, and other energetic astronomical objects – including black holes or cold, dark objects that emit no visible light. While radio telescopes don’t take pictures in the same way visible-light telescopes do, the radio signals detected are amplified and converted into data that can be analyzed and used to create images. 

But radio telescopes can also be used to transmit and reflect radio light off planetary bodies in our Solar System. This is called planetary radar or Solar System radar.

This collage shows six planetary radar observations of 2011 AG5 a day after the asteroid made its close approach to Earth on Feb. 3, 2023. With dimensions comparable to the Empire State Building, 2011 AG5 is one of the most elongated asteroids to be observed by planetary radar to date. Credit: NASA/JPL-Caltech

What is planetary radar and how does it work?

“Essentially we have a flashlight that works in radio waves,” Taylor explained. “Our narrow flashlight beam does not look at the whole sky, but we point it in a very precise location – the surface of an asteroid or moon. We know very well what our flashlight’s properties are, so we know exactly what we send out. When we receive the echo back from wherever we pointed our flashlight, we analyze that signal and see how it changed compared to what we transmitted.”

That’s what makes planetary radar so powerful and different from any other type of astronomy.  

“When astronomers are studying light that is being made by a star, or galaxy, they’re trying to figure out its properties,” Taylor said. “But with radar, we already know what the properties of the signals are, and we leverage that to figure out the properties of whatever we bounced the signals off of. That allows us to characterize planetary bodies – like their shape, speed, and trajectory. That’s especially important for hazardous objects that might stray too close to Earth.”

In the past, planetary radar has been used to image asteroids, but also precisely measure the position and motion of the planets, allowing us to land spacecraft on Mars and to explore the outer Solar System. The technique has also made surprising discoveries, such as the finding the presence of water ice on Mercury.  

The 70m telescope at the Goldstone Deep Space Communications Complex in California’s Mojave Desert. (NASA/JPL)

Because radio waves are much longer than visible light waves, radio astronomy requires large antennas. The 70-meter Goldstone antenna located in California’s Mojave Desert, is primarily used to communicate with spacecraft as part of NASA’s Deep Space network. But it is also frequently used for planetary radar to study near Earth asteroids, and — as previously mentioned — is the only facility currently available to perform high-power planetary radar. (There are, however, are smaller facilities that can perform planetary radar, including smaller telescopes at the Goldstone site and a few in Australia, but they do not have the same scale of transmitter power as the Goldstone 70-meter dish.) Previously, the workhorse for planetary radar was the 1,000-foot-diameter (305 meters) Arecibo Observatory, which was about 20 times more sensitive and could detect asteroids about twice as far away than the Goldstone 70 meter.

However, because Arecibo’s dish was stationary and built inside a round sinkhole, it was fixed to the Earth and could only view whatever part of the sky happened to be straight overhead. That meant Arecibo’s dish could only see about one-third of the sky. Goldstone is fully steerable, can see about 80 percent of the sky, can track objects several times longer per day, and can image asteroids at finer spatial resolution.

ngRADAR

The Robert C. Byrd Green Bank Telescope is the world’s largest fully steerable radio telescope. The maneuverability of its large 100-meter dish allows it to quickly track objects across its field of view, and see 85% of the sky.

The GBT’s new radar system will introduce a high-resolution tool that will be a vast upgrade, collecting data at higher resolutions and at wavelengths not previously available. Scientists at GBT and the National Radio Astronomy Observatory (NRAO) are also developing advanced data reduction and analysis tools that have not been available before, providing astronomers with unprecedented planetary radar capabilities.

To test out the proof of concept, Taylor and his team worked with the company Raytheon — a long-time developer of radar systems for both the military and science applications — to build a small version of the transmitter, with a lot less power.

“Our friends at Raytheon built a transmitter that could output 700 watts, so about half the power of a microwave oven,” Taylor said. “Ultimately, we want to build a system with 500 kilowatts, so up by a factor of a thousand. But even with 700 watts, we were able to do some really impressive observations.”

Radar image of the Apollo 15 landing site. Credit: Raytheon/NRAO.

GBT’s planetary radar was aimed at the Moon, specifically at the Apollo 15 landing site in Hadley Rille, and at the giant Tycho Crater’s surface, and radar echoes were received with NRAO’s ten 25-meter VLBA antennas. At Tycho, the crater was captured with 5-meter resolution, showing unprecedented detail of the Moon’s surface from Earth. Taylor said the resolution with the ngRADAR prototype approached the optical resolution on Lunar Reconnaissance Orbiter, taking images with its high-resolution cameras from orbit around the Moon.

“The images of the crater floor were actually breathtaking,” Taylor said. “It’s pretty amazing what we’ve been able to capture so far, using less power than a common household appliance.”

A Synthetic Aperture Radar image of the Moon’s Tycho Crater, showing 5-meter resolution detail. Image credit Raytheon.

Additionally, the prototype radar also detected a potentially hazardous asteroid named (231937) 2001 FO32, which happened to be flying past Earth at about six times more distant than the Moon during their radar pings. The asteroid is considered potentially hazardous because of its size, approximately 1 kilometer in diameter, along with how close it can get to Earth, at just over 2 million kilometers away during the observations in 2021. The asteroid’s detection appeared as a spike in their data.

“Just from the spike in our data, we can now figure out how fast this object is moving, determine its orbit, and figure out its trajectory in the future,” Taylor explained. “We can determine its impact risk and assess how much of a hazard it is, and even constrain its spin state, its size, its composition, its scattering properties, and so on. So, even though the data spike doesn’t look like much, that one little detection can tell you a lot of information about the asteroid.”

Radar signals transmitted by the GBT will reflect off astronomical objects, and those reflected signals will be received by the Very Long Baseline Array (VLBA), a network of ten observing stations located across the United States.

“The idea is for GBT is to do the transmitting almost constantly and the VLBA — either all ten of those or any subset of those telescopes — doing the receiving,” Taylor said. “This new system will allow us to characterize the surfaces of many different objects in a different frequency or wavelength that hasn’t been used before.”

Next: Part 2 of this series will look at the details of ngRADAR, the history of planetary radar, and take you up close to the GBT.

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Categories: Astronomy

Hot Gas is Being Vented Away from the Center of the Milky Way

Thu, 05/30/2024 - 5:33am

Studying gas in the Universe is no easy task. We often look to ‘non-visible’ wavelengths of the electromagnetic spectrum such as X-rays. The Chandra X-Ray observatory has been observing a vent of hot gas blowing away from the centre of the Milky Way. Located about 26,000 light years away, the jet extends for hundreds of light years and is perpendicular to the disk of the Galaxy. It is now thought the gas has been forced away from the centre of the Milky Way because of a collision with cooler gas lying in its path and creating shockwaves. 

The Chandra X-ray observatory was launched by NASA in 1999. Since then, it has been orbiting above the atmosphere, probing space in high energy X-rays. It provides us with stunning, high resolution data that allows us to study black holes, supernova remnants and other high energy events in unprecedented detail. 

Artist’s illustration of Chandra

Using the power of the Chandra telescope to study the centre of our Galaxy, ridges that were perpendicular to the plane of the Milky Way were seen at a distance of 26,000 light years. The team of researchers believe the ridges are the walls of a tunnel that is shaped like a cylinder. The structure helps to funnel hot gas along, much as a chimney does over a fireplace, and away from the centre of the Galaxy. The vent is about 700 light years long and extends away from the core of the Milky Way. 

The structure was previously spotted using earlier data from Chandra but also from the XMM-Newton project too. The radio emission have been detected by the MeerKAT radio array ( based in South Africa this array is made up of 64 receivers ) too and shows the powerful effects of magnetic fields channeling gas along the chimney. Lead scientist Scott Mackey from the University of Chicago said “We suspected that magnetic fields are acting as the walls of the chimney and that hot gas is travelling up through them, like smoke.” He continued “Now we’ve discovered an exhaust vent near the top of the chimney.”

Exploring the Chandra data, the team think the vent formed from a collision as hot rising gas through the tunnel collided with cooler gas. The bright ridges in the walls are thought to be the result of shock waves generated by the collision. The left portion of the tunnel seems brighter because the gas flowing upwards has struck the chimney at a more direct angle and imparted more energy. 

As for the origins of the hot gas, it is thought this is coming from material falling into the black hole at the centre of the Galaxy. As material accretes around the black hole, a series of events can cause material to be ejected from the accretion disk, forcing the gas along the chimney.  X-ray flares are thought to take place every couple of hundred years near the black hole where blasts of X-ray radiation reflects off a build up of hot plasma. These flares are thought to drive the hot gas upwards and out through the vent. 

The diagonal line of bright objects in this image of the heart of our Milky Way Galaxy are all powerful sources of radio waves. The bright center is the home of the supermassive black hole, Sagittarius A*. The dense, bright circles are the nurseries of new, hot stars and the bubbles are the graveyards of exploded, massive stars. The thread-like shapes are not yet understood, but probably trace powerful magnetic field lines. This giant image was assembled from observations made by the Very Large Array (VLA).

One of the outstanding questions requiring extra research is the ultimate driving force behind the energy release. Is it a one off major event like the death of a star as it is ripped apart by the black hole or a series of smaller events that build up? Further studies are needed to fully understand the events at the centre of the Galaxy and to build a fuller picture of the nature of the vent at the centre of the Galaxy. 

Source : NASA’s Chandra Notices the Galactic Center is Venting

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Categories: Astronomy

How Much Water Would a Self-Sustaining Moonbase Need?

Wed, 05/29/2024 - 11:48pm

As humanity returns to the Moon in the next few years, they’re going to need water to survive. While resupplies from Earth would work for a time, eventually the lunar base would have to become self-sustaining? So, how much water would be required to make this happen? This is what a recently submitted study hopes to address as a team of researchers from Baylor University explored water management scenarios for a self-sustaining moonbase, including the appropriate location of the base and how the water would be extracted and treated for safe consumption using appropriate personnel.

Here, Universe Today discusses this research with Dr. Jeffrey Lee, who is an assistant adjunct professor in the Center for Astrophysics, Space Physics & Engineering Research at Baylor University, and lead author of the study, regarding the motivation behind the study, significant results, the importance of having a self-sustaining moonbase, and what implications this study could have for the upcoming Artemis missions. Therefore, what is the motivation behind this study?

Dr. Lee tells Universe Today, “This paper is actually an eclectic diversion for me from my astrophysics research on primordial black holes, early universe cosmology, breakthrough propulsion physics, and my geophysics research on asteroid impacts. If human missions throughout the Solar System, particularly to Mars, are to be realized, then a permanent lunar facility seems to be a logical early step.”

For the study, the researchers investigated water management requirements for a 100-person self-sustaining lunar base measured at 500 m x 100 x 6 m (1640 ft x 328 ft x 20 ft), including the location of the lunar base near water ice deposits, the technology required to convert the water ice to water vapor (since liquid water can’t exist on the Moon), and the technology required for water treatment and recovery that would result in safe consumption for the 100-person base. The study used the current water usage estimates for American households, which is approximately 100 gallons per day (GPD) per person, which includes cleaning, cooking, drinking, flushing toilets, and washing clothes.

Additionally, the researchers examined the amount of water required for agricultural, technical, and overall needs for the lunar base. Regarding the location of the lunar base, the researchers deduced that the best location for the base would be either near, or exactly on, the Shackleton-de Gerlache Ridge, which is located at 89.9°S 0.0°E, or almost directly on the lunar south pole. The reason this location is ideal for water ice deposits is because Shackleton Crater resides within a permanently shadowed region (PSR), meaning it is shrouded in permanent darkness due to the Moon’s small axial tilt, and water ice has potentially built up over billions of years.

In the end, the team concluded the water requirements for the 100-person lunar base for human, agricultural, and technical needs are 12.3, 72, and 2 acre-feet per year. For context, one acre-foot is equivalent to approximately 326,000 gallons, so a 100-person lunar base would need more than 4,000,000 gallons per year for human needs, more than 23,000,000 gallons per year for agricultural needs, and 652,000 gallons per year for technical needs. So, based on these findings, what were the most significant results from this study, and what follow-up studies are currently in the works or being planned?

Dr. Lee tells Universe Today, “There is good evidence that sufficient water exists on the Moon to support a permanent lunar colony, and the acquisition, treatment, and distribution of the lunar water can be achieved with current technology. An appropriate administrative structure will be necessary to oversee all aspects of lunar water. The relative scarcity and management of water on the Moon can potentially provide insight for improving the management of water on Earth. The next study for my group will be to investigate the ways in which the management of lunar water could help to improve terrestrial water management. However, the timeline for this research is yet to be determined.”

The study discusses in-situ resource utilization (ISRU), which is using available, on-site resources for both sustainability and survivability. In this case, using water ice deposits on the Moon, and specifically near the south pole of the Moon, to meet the water needs of a 100-person, self-sustaining lunar base. The potential for NASA using ISRU has gained considerable traction in the last few years since sending water from the Earth to the Moon could prove to be extremely costly. But aside from the financial risks, if a resupply mission gets delayed or fails on the way to the Moon, the crew could face significant danger. Therefore, learning to “live off the land” for a lunar base could prove to be a viable, long-term option for mitigating the need of resupply missions from Earth. But what additional importance could a self-sustaining moonbase also provide?

Dr. Lee tells Universe Today, “Over the years, there has been a groundswell of excitement at the prospect of colonizing Mars. Indeed, at present, we are conceivably able to mount a short-term human voyage to the Red Planet in which the astronauts would collect samples, conduct experiments, plant flags, and when the next launch window occurs, return to Earth. However, the permanent colonization of Mars is much more ambitious and challenging. Mars is much farther away than the Moon, requiring 9 months to get there and a round trip time of 21 months (a 3-month stay on Mars is needed until the next launch window arrives).”

NASA’s goal is to send humans to Mars through the agency’s Moon to Mars Architecture, which is an elaborate, years-long endeavor to develop the necessary technologies on the Moon for use during a crewed mission to the Red Planet. This includes science, infrastructure, transportation, habitation, and operations, just to name a few. However, as noted, while we can (possibly) send humans to the Red Planet for short-term stays with our current technology, a long-term human presence on Mars would require significantly more time and resources.  

Dr. Lee tells Universe Today, “Beyond low Earth orbit, the Moon is a logical next destination. Lunar colonization is technologically achievable, and in comparison to Martian colonization, it is far easier. Being capable of establishing a moonbase seems like an obvious prerequisite for establishing a Mars base. Furthermore, the Moon would be an excellent jumping off point for further Solar System colonization including potentially the eventual establishment of small colonies in the interiors of Near-Earth Asteroids. Additionally, some have suggested that the Moon is an ideal location from which the interception of Earth-bound asteroids could be conducted.”

This study comes as NASA’s Artemis program plans to land the first woman and person of color on the lunar surface in the next few years. The current landing sites of the Artemis missions are near the south pole to access nearby water ice deposits within the aforementioned PSRs and could be ideal to develop ISRU technologies that can also be used on future Mars crewed missions, as well. Therefore, what implications could this study have for the upcoming Artemis missions?

“Short term lunar visits, such as the planned Artemis missions would not require lunar water,” Dr. Lee tells Universe Today. “In these instances, sufficient water could be brought from Earth. However, if at some point in the future, a lunar colony were to become a priority, future Artemis missions could serve to provide valuable in situ information about the presence and abundance of lunar water, particularly at the lunar south pole and in proximity to the Shackleton Crater (an ideal area for a moonbase).”

How will water management play a role in a self-sustaining lunar base in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

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Categories: Astronomy

Black Holes: Why study them? What makes them so fascinating?

Wed, 05/29/2024 - 9:42pm

Over the last few months, Universe Today has explored a plethora of scientific fields, including impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, cosmochemistry, meteorites, radio astronomy, extremophiles, and organic chemistry, and how these various disciplines help scientists and the public better understand our place in the cosmos.

Here, we will discuss the fascinating and mysterious field of black holes with Dr. Gaurav Khanna, who is a Professor in the Department of Physics at the University of Rhode Island, regarding the importance of studying black holes, the benefits and challenges, exciting aspects of studying black holes, and how upcoming students with to pursue studying black holes. So, what is the importance of studying black holes?

“Gravity is the oldest known, but the least understood force in nature,” Dr. Khanna tells Universe Today. “For students of gravity, black holes are amongst the most interesting objects to study because gravity is the dominant force there — in fact, it is infinitely strong! Then there are astrophysical reasons of interest in black holes. They play important roles in galaxies, perhaps even in the large-scale behavior of the universe and more. The other thing to note about black holes is that they are very ‘simple’ especially when compared to stars and other astrophysical objects. This is a consequence of the so-called ‘no hair’ theorem that states that black holes can be fully characterized by only 3 attributes — their mass, charge and spin. That simplicity makes them particularly appealing to study and research.”

Black holes are known for exhibiting gravity so strong that light can’t even escape, and while Albert Einstein’s theory of general relativity in 1915 is often credited with first proposing the concept of black holes, the concept of an object whose size and gravity would not allow light to escape was first proposed in a November 1784 letter by English philosopher and clergyman, John Mitchell. In this letter, Mitchell referred to these objects as “dark stars” since he postulated that stars whose diameters exceeded 500 times that of our Sun’s diameter would trigger the formation of these objects. Additionally, he suggested that gravitational waves influencing nearby celestial bodies would enable these objects to be detected.

Fast forward to Einstein’s theory of general relativity, which also predicted both the existence of black holes and gravitational waves, both of which continued to be scrutinized throughout the 20th century, which includes what’s called the “golden age of general relativity” during the 1960s and 1970s. This includes the first object accepted by the scientific community as a black hole, called Cygnus X-1, which was discovered in 1964. However, it took another 52 years for the existence of gravitational waves to be confirmed through a black hole merger, which was accomplished by the LIGO Scientific Collaboration. Therefore, given the extensive history combined with key discoveries only occurring within the last few years, what are some of the benefits and challenges of studying black holes?

Dr. Khanna tells Universe Today, “As I stated above, studying black holes, which are a consequence of Einstein’s relativity theory, offers insight on the nature of gravity, space and time at the most fundamental levels. As physicists, we are yet to develop a complete understanding of the quantum nature of gravity, and black holes are the key to unlocking that mystery. On the challenges, I’d say that the clearest one perhaps is that black holes can only be observed indirectly. Unlike stars, since they don’t emit radiation themselves, it is difficult for astronomers to collect data on them. At best, we can observe their influence on their environment (like gas, stars, etc.) and infer their properties and behavior. On the theoretical side, while it is indeed true that black holes are very “simple” compared to stars, there are still challenges. The mathematics and physics that describe them is fairly advanced and even computer simulations involving them are challenging requiring massive processing power and memory.”

While it took over 100 years between Einstein introducing his theory of general relativity in 1915 and the confirmation of gravitational waves in 2016, it only took another three years for astronomers to publish the first direct image of a black hole at the center of the Messier 87 galaxy. The results were published in The Astrophysical Journal Letters and based on observations taken in 2017 by the powerful Event Horizon Telescope (EHT). While Messier 87 is located approximately 53 million light-years from Earth, the closest hypothesized black hole, Gaia BH1, is located approximately 1,560 light-years from Earth. In 2022, astronomers published a direct image of Sagittarius A*, which is the supermassive black hole at the center of our Milky Way Galaxy.

Additionally, scientists hypothesize the number of black holes in our Milky Way Galaxy is in the hundreds of millions, despite only a few dozen known black holes having been confirmed, thus far. But what are the most exciting aspects about black holes that Dr. Khanna has studied during his career?

Dr. Khanna tells Universe Today, “I suppose I’d probably refer to my recent work on how very rapidly rotating black holes attempt to ‘grow hair’ but ultimately fail. The project is interesting because it appears to suggest a violation of the ‘no hair’ theorem that I mentioned earlier, but it ultimately doesn’t. So, it is provocative, but then relieving! More importantly, we are now using the main context of that research to develop a new observational ‘signature’ or test for rapidly rotating black holes, a.k.a. near-extremal black holes. Such black holes have several peculiar properties and aspects and are an area of active research.”

Black holes are studied by astronomers, physicists, and astrophysicists, who use a combination of theory and observations to construct what black holes might look like, and in rare cases, as discussed, obtain direct images of them. Regarding theory, researchers use mathematical calculations and computer models to simulate what black holes might look like, and then have used powerful ground-based telescopes like EHT to obtain the few direct images of black holes. It is important to note that these direct images don’t capture the black hole itself, but the gases that are encircling the black hole’s event horizon, or the unofficial boundary where light can’t escape the black hole. But what advice can Dr. Khanna offer upcoming students who wish to pursue studying black holes?

Dr. Khanna tells Universe Today, “I would offer them a lot of encouragement! There is a lot to do in this space and many mysteries to solve. New observations are going to open many new doors and brand-new avenues for research. This is amongst the best times to be a black hole astrophysicist!”

Dr. Khanna continues, “The one thing that I could say perhaps that isn’t as much emphasized elsewhere is about computing as a tool to study black holes. Mostly there is heavy emphasis on learning advanced mathematics as the background for serious research in black holes — and for good reason — that continues to be critical for every student of Einstein’s relativity theory which is the foundation for black hole physics.  In recent years, computer simulations have advanced rapidly, and one can now make major discoveries about deep questions using computational tools. In the long run, computer programming would be a very promising tool for advancing research in this field and many others as well.”

How will black holes help us better understand our place in the universe in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

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Categories: Astronomy

There’s Another, More Boring Explanation for those Dyson Sphere Candidate Stars

Wed, 05/29/2024 - 8:28pm

Dyson Spheres have been a tantalising digression in the hunt for alien intelligence. Just recently seven stars have been identified as potential candidates with most of their radiation given off in the infrared wavelengths. Potentially this is the signature of heat from a matrix of spacecraft around the star but alas, a new paper has another slightly less exciting explanation; dust obscured galaxies. 

There are a number of ways to hunt for aliens and one of them is to look for signs of large scale projects in space. Enter the Dyson Sphere. The idea was first proposed by Freeman Dyson in 1960 to describe that an advanced civilisations would position power collectors and even habitats around a star to harness its power. Eventually such infrastructure would likely surround the entire star and Dyson reasoned that a signature would be detectable such as an excess of infrared radiation. 

A Type II civilization is one that can directly harvest the energy of its star using a Dyson Sphere or something similar. Credit: Fraser Cain (with Midjourney)

The findings of Project Hephaistos revealed the seven M type stars from a sample of 5 million stars detected by Gaia. The astrometric satellite has been used to map stars in the Milky Way and has been of profound benefit to many pieces of research. Data from 2MASS (the Two Micron All Sky Survey) and WISE (the Wide Field Infrared Survey Explorer) were also used to identify the stars that seemed to display the expected Infrared excess. 

Artist’s impression of the Gaia spacecraft detecting artificial signals from a distant star system. In this synchronization scheme, the star system’s inhabitants send the signal shortly after witnessing a supernova, which is also seen by telescopes on Earth. (Credit: Danielle Futselaar / Breakthrough Listen)

In the recent paper by lead author Tongtian Ren and team, they explore the findings of the project and delve into the possible nature of the candidate spheres. The team cross-matched the information from data from the Very Large Array Sky Survey (VLASS) and several other radio surveys of the sky. They searched for radio sources within a radius of 10 arc seconds of the Gaia positions of the candidates. Note that the full Moon is 1,860 arc seconds across. 

Radio sources were found for three of the candidates, those named A, B and G. The accuracy of the sources was within 4.9, 0.4 and 5 arc seconds respectively and candidate G was found in multiple radio surveys. The conclusion from the team is that the seven stars are less likely to be Dyson Spheres but instead some sort of extra galactic phenomenon. The most likely explanation is a distant galaxy obscured by dust! The presence of the dust would contaminate the Infrared energy distribution in the spectra of the two objects. The other candidate, candidate B is also thought to be a distant galaxy but one that was within very close line of sight of an M type dwarf star. 

Very similar to candidates A and B, candidate G has a spectrum that reveals a radio loud active galactic nuclei with superluminal jets extending out. It is likely that galaxies are distant quasars which emit enormous amounts of radiation, but the obscuring hot dust clouds obscure most radiation, except infrared. 

What of the other four candidates? To date, no matching radio source has been found. That does not mean the hot, dust obscured galaxy model is not an adequate explanation but just that possible higher resolution radio surveys are required. Of course it may also be that they really are spheres of technology around distant stars. As much as I would love that to be true, there is no evidence for this yet. 

Source : Background Contamination of the Project Hephaistos Dyson Spheres Candidates

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Categories: Astronomy

Hundreds of Massive Stars Have Simply Disappeared

Wed, 05/29/2024 - 7:35pm

The lifecycle of a star is regularly articulated as formation taking place inside vast clouds of gas and dust and then ending either as a planetary nebula or supernova explosion. In the last 70 years however, there seems to be a number of massive stars that are just disappearing! According to stellar evolution models, they should be exploding as supernova but instead, they just seem to vanish. A team of researchers have studied the behaviour of star VFTS 243 – a main sequence star with a black hole companion – and now believe it, like the others, have just collapsed, imploding into a black hole!

During the life of a star, the inward pulling force of gravity is balanced by the outward pushing thermonuclear force (the result of fusion in the core.) Once the core is rich in iron, as happens with massive stars about 8 times more massive than the Sun, the fusion process ceases as does the thermonuclear force. With the cessation of the force, the core collapses, the outer layers collapse in on the core and bounce back out as a massive explosion known as a supernova. The actual mechanism of the explosion and the formation of the compact object that is left behind from the core is still the subject of a lot of debate. 

The supernova process is one of the most powerful explosions in the universe. As the star collapses, a shockwave is produced that can create fusion in the outer shell of the progenitor star. The reactions can create new elements heavier than iron. In a paper recently published by an international team of astronomers led by Alejandro Vigna-Gómez from the Max Planck Institute for Astrophysics in Germany the team shed new light on the process. They showed that it is possible for a star to be so massive that its gargantuan force of gravity can be strong enough that even the supernova explosion is not able to take place.

The Fred Lawrence Whipple Observatory’s 48-inch telescope captured this visible-light image of the Pinwheel galaxy (Messier 101) in June 2023. The location of supernova 2023ixf is circled. The observatory, located on Mount Hopkins in Arizona, is operated by the Center for Astrophysics | Harvard & Smithsonian. Hiramatsu et al. 2023/Sebastian Gomez (STScI)

The team’s discovery seems to be linked to the concept of disappearing stars. Over the last few years, it has become evident that some stars seem to just vanish from view, neither passing through the planetary nebula phase nor going supernova. The discovery of supermassive stars undergoing complete collapse without supernova now provides a good explanation for the phenomenon. 

The team reached their conclusion when they explored an object known as VFTS 243; a binary system which includes a star thought to be 25 times more massive than the Sun and a blackhole 10 times more massive than the Sun. Both objects orbit a common centre of gravity over a period of 10.4 days and lie in the Tarantula Nebula in the Large Magellanic Cloud – 160,000 light years away. The binary system is not the first of its kind to be discovered, such systems have been known about for decades. 

30 Doradus, also known as the Tarantula Nebula, is a region in the Large Magellanic Cloud. Streamlines show the magnetic field morphology from SOFIA HAWC+ polarization maps. These are superimposed on a composite image captured by the European Southern Observatory’s Very Large Telescope and the Visible and Infrared Survey Telescope for Astronomy. Credit: Background: ESO, M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit. Streamlines: NASA/SOFIA

Studying the system revealed the orbit was almost circular. Given that one of the stars had collapsed into a black hole, the nearly circular orbit and the lack of any evidence of an explosion all point to a star that collapsed completely. The complete collapse meant that all matter from the star collapsed into the blackhole and no material escaped out as a supernova. Could it be then that the team have finally revealed the mechanism by which massive stars have been vanishing? It certainly looks like it but further observations of binary systems with stars and black holes is required to confirm. 

Source : Constraints on Neutrino Natal Kicks from Black-Hole Binary VFTS 243

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Categories: Astronomy

What’s Under This Hole on the Surface of Mars?

Wed, 05/29/2024 - 7:31pm

Human visitors to Mars need somewhere to shelter from the radiation, temperature swings, and dust storms that plague the planet. If the planet is anything like Earth or the Moon, it may have large underground lava tubes that could house shelters. Collapsed sections of lava tubes, called skylights, could provide access to these subterranean refuges.

Does this hole on Mars lead to a larger underground cavern?

This image was captured by the High-Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter (MRO). The pit is only a few meters across and is in the Arsia Mons region of Mars. Arsia Mons is one of the three dormant volcanos in the Tharsis Montes group of three volcanos.

This colourized image of the surface of Mars was created with data from the Mars Reconnaissance Orbiter. The line of three volcanoes is Tharsis Montes, with Olympus Mons to the northwest and Valles Marineris to the east. Arsia Mons is the southernmost volcano of the three that comprise Tharsis Montes. Image: NASA/JPL-Caltech/ Arizona State University

The Tharsis Region of Tharsis Bulge is a vast volcanic plain that’s thousands of kilometres across. It’s elevated compared to the rest of Mars and averages about 10km (33,000 ft) above the planet’s mean elevation. The region was volcanically active in the past, obviously, and features like the pit are a direct result of ancient volcanic activity.

Several pits in the Arsia Mons region may be collapsed skylights or openings into subterranean lava tubes. However, there is much uncertainty. An image of one of them shows an illuminated sidewall, which could indicate that it’s just a cylindrical pit.

These images of a pit near Arsia Mons were captured several years ago. The image on the left was captured first, and scientists wondered if it could lead to a lava tube or cave. Then, the image on the right, showing a side wall, was captured. The side wall could indicate that there’s no tube or cave. Image Credit: NASA/JPL/University of Arizona

The hole in the featured image could be only a pit or shaft and not an entrance to a cave or lava tube. They’re found on Hawaiian volcanos, where they’re called pit craters. They don’t connect to long caves or lava tubes. They’re the result of a collapse that happened much deeper underground.

These four sequential images show how pit craters form. As volcanos erupt and settle, cracks form. They slowly migrate upwards, and rocks above them start to fall into them. Eventually, the upward migrating crack reaches the surface, and the roof caves in. On Earth, plants will eventually colonize the crater. On Mars, they stay much the same as when they collapsed. Image Credit: US National Park Service.

In Hawaii, the pit craters range from 6 to 186 m (20 to 610 feet) deep and from 8 to 1140 m (26 to 3,740 feet) wide. The Arsia Mons pit in the leading image is only about 178 m (584 feet) deep.

We have a much better understanding of lava pits and tubes on the Moon than we do on Mars. We know some of them are thermally stable at about 17 C (63 F.) We also have better images of them, with intriguing glimpses of boulder-covered floors.

Spectacular high Sun view of the Mare Tranquillitatis pit crater revealing boulders on an otherwise smooth floor. The 100-meter pit may provide access to a lunar lava tube. Image Credit: By NASA/GSFC/Arizona State University – http://photojournal.jpl.nasa.gov/catalog/PIA13518, Public Domain, https://commons.wikimedia.org/w/index.php?curid=54853313

Lots of thinking is going into how to explore these lunar caves and lava tubes, including conceptual designs for robots that could explore them. Maybe on the Moon, astronauts could take shelter in inflatable habitats inside these tubes, where they’re protected from temperature swings, radiation, and micrometeorites.

But Mars is another question. There’s no reason that lava tubes shouldn’t exist on Mars. In fact, Mars’ gravity is much weaker than Earth’s, and that should allow for much larger tubes. Images of Mars show rilles, which are collapsed tubes. It seems likely that not all of these tubes have collapsed to form rilles.

One pit on the Martian volcano, Pavis Mons, is particularly intriguing. There’s some kind of void under the pit, but the nature of the pit is difficult to ascertain. Is it a lava tube? If it is, it dwarfs most tubes on Earth.

Martian lava tubes are still a mystery. Scientists have found plenty of morphological evidence suggesting that they’re plentiful. But in science, you can’t assume they’re there, even though it seems likely that they are. There’s no clear reason why they wouldn’t be. Could they one day provide shelter for astronauts? Maybe.

We need a robotic mission to explore them first.

The post What’s Under This Hole on the Surface of Mars? appeared first on Universe Today.

Categories: Astronomy

Sorry Spock, But “Vulcan” Isn’t a Planet After All

Wed, 05/29/2024 - 4:29pm

In 2018, astronomers detected an exoplanet around the star 40 Eridani. It’s about 16 light-years away in the constellation Eridanus. The discovery generated a wave of interest for a couple of reasons. Not only is it the closest Super-Earth around a star similar to our Sun, but the star system is the fictional home of Star Trek’s Vulcan science officer, Mr. Spock.

It’s always fun when a real science discovery lines up with science fiction.

Eridani’s other name is HD 26965, and it’s actually a triple-star system. Astronomers discovered the system’s lone planet, Eridani b, using the radial velocity method. Orbiting planets tug on their stars, and the star’s movement creates a change in its spectrum. Astronomical telescopes with spectrometers can detect the changes.

Jian Ge, an astronomy professor at the University of Florida, led the study that presented the discovery in 2018. At the time, Ge said in a press release, “The new planet is a ‘super-Earth’ orbiting the star HD 26965, which is only 16 light years from Earth, making it the closest super-Earth orbiting another Sun-like star. The planet is roughly twice the size of Earth and orbits its star with a 42-day period just inside the star’s optimal habitable zone.”

A super-Earth in the habitable zone around a Sun-similar star ‘only’ 16 light-years away is an intriguing discovery. Its link with a beloved Star Trek character gave the discovery wings, and word spread.

However, in the intervening years, follow-up observations have not confirmed Eridani b’s existence. A 2021 study suggested that the change in the star’s spectrum was a false positive. Now, a new study says that the exoplanet fondly named Vulcan does not exist.

The study is “The Death of Vulcan: NEID Reveals That the Planet Candidate Orbiting HD 26965 Is Stellar Activity.” It’s published in The Astronomical Journal, and the lead author is Abigail Burrows, an astronomer at Dartmouth College.

“We revisit the long-studied radial velocity (RV) target HD 26965 using recent observations from the NASA-NSF “NEID” precision Doppler facility,” Burrows and her co-authors write. After a deeper, line-by-line analysis of the radial velocity data, “… we demonstrate that the claimed 45-day signal previously identified as a planet candidate is most likely an activity-induced signal.”

Activity-induced signal means that the signal comes from the star’s activity, not from the external tug of an exoplanet.

Vulcan’s initial detection was based on data from the Dharma Planet Survey (DPS.) DPS monitored about 150 nearby Sun-like stars for changes in their spectra. Data from the Keck Telescope and the HARPS planet-finding spectrograph also contributed to the discovery.

When the planet was detected in 2018, the discoverers recommended caution. They presented the data as they collected it, along with their best interpretation. That’s standard in science, and they were careful in calling it a candidate planet. In their paper, they also discussed “the possibility that the RV signal is actually produced by stellar rotation modulated activity.” That activity could be sunspots, convection irregularities, or other things.

But in the end, they concluded that what they were seeing was likely a planet.

“By carefully examining the RV data in the active and quiet phases of the star, and after carefully considering all possible stellar activity sources, we concluded that the coherent signal seen from HD 26965 is most likely from a planet, with some RV noise contributed by stellar activity,” the authors wrote in the 2018 paper.

The rest of us were happy to agree because finding a super-Earth around a nearby Sun-like star is the kind of thing we hope to find.

“Men sometimes see exactly what they wish to see.”

-Spock of Vulcan

Sadly for Vulcan, the newest research shows that the stellar activity isn’t noise. It accounts for the entire signal.

The new results are based on NEID, the NN-explore Exoplanet Investigations with Doppler spectroscopy. It’s a high-resolution spectrometer attached to the WIYN (Wisconsin-Indiana-Yale-NOIRLab) telescope at Kitt Peak Observatory. The researchers used NEID to capture 63 spectra from Eridani over a six-month period.

NEID revealed a lot of information about the star, including things like contrast and radial velocity. Together, NEID data paints a more complete picture of the star and its activity. In this new work, Burrows and her co-researchers showed that all of this activity lines up with the star’s 42-day rotation period.

“All measurements show a strong signal at or near the 42-day stellar rotation period,” they write.

This figure from the study shows NEID data on the left. “All data show clear rotational modulation at or near the 42-day period,” the authors write. The right shows periodograms for the data, which show “clear power at the stellar rotation period of ?42 days.” Image Credit: Burrows et al. 2024

The authors write that their work “points toward a decaying starspot or plage” as the source of the signal. A plage is a bright spot on a star’s chromosphere. They used a variety of methods to reach this conclusion. “While each of these methods taken individually may not rule out a potential planetary signal at the same phase and period as the activity signal, collectively, our analyses show that an activity hypothesis is favoured over the specific planet claimed in Ma et al. (2018),” they conclude.

“When you eliminate the impossible, whatever remains, however improbable, must be the truth.”

Spock of Vulcan

The authors of the new paper didn’t set out to debunk Vulcan. Their paper is part of an effort to better understand the periodic and quasi-periodic spectral changes from Sun-like stars. Without a better understanding, annoying false positives will cloud our understanding of exoplanets, especially Earth-like ones around Sun-like stars. “To reach the precision necessary to detect temperate, Earth-mass extrasolar planets (exoplanets) around Sun-like stars using the radial velocity (RV) technique, the community must improve Doppler measurement precision significantly from the current state of the art,” they write.

“Detecting and characterizing these exo-Earths is vital for future spaceborne direct imaging missions, which will set the scientific priorities for the coming decade,” the authors explain.

The post Sorry Spock, But “Vulcan” Isn’t a Planet After All appeared first on Universe Today.

Categories: Astronomy

A Mini-Neptune in the Habitable Zone in a Binary Star System

Wed, 05/29/2024 - 3:26pm

Sometimes, it seems like habitable worlds can pop up almost anywhere in the universe. A recent paper from a team of citizen scientists led by researchers at the Flatiron Institute might have found an excellent candidate to look for one – on a moon orbiting a mini-Neptune orbiting a star that is also orbited by another star.

That’s a lot of things orbiting each other, so let’s dive into some details of the star system known as TOI 4633. It has two potential planets. One has a relatively short 34-day orbit but whose existence was only found by radial velocity measurements, as it doesn’t cross between the Earth and its host star. It also has yet to be confirmed by exoplanet hunters.

Another planet, known for now at TOI 4633c, is much more intriguing. It falls into the size category of a “mini-Neptune,” meaning it is slightly smaller than the 8th planet in our solar system but is likely still a gas giant with a thick atmosphere. It orbits its host star once every 272 days – making it one of the 40 longest-orbiting planets out of the thousands discovered so far.

Binaries are just one of a class of multiple-star systems, as Fraser explains.

That long orbit also puts it in the habitable zone of its host star – about .85 AU away from the G-type star it is orbiting. Being in the habitable zone would imply that liquid water could exist on its surface. However, the size of the planet and the likely density of its atmosphere would rule out the possibility of surface water on the planet itself.

However, there is a relatively good chance that TOI 4633c could have a moon. Planets with longer orbits tend to accrue them (hence why Venus and Mercury don’t have any in our own solar system). Such a small world wouldn’t have the same restrictive constraints as its gas-giant host planet, meaning it could potentially be habitable, such as the moons Pandora in the Avatar franchise or Endor in Star Wars.

But what makes this system even more unique is that the star TOI 4633c is orbiting is itself being orbited by another star. It wasn’t long ago that we weren’t even sure if planets could exist in these “binary” systems, and how strange life might be on one has become prominent recently with the popularity of The Three-Body Problem. But in theory, binary systems have habitable zones, and planets can survive in a stable orbit around at least one of the stars.

TESS’ primary mission is compete, but its data is still a treasure trove of new discoveries, as Fraser covers.

The smaller star orbits around its larger binary companion only once every 230 years and gets close enough to the other star to be considered relatively close by interstellar standards. As of now, it’s unclear what, if any, effect this proximity to another star would have on TOI 4633c, but it’s doubtful that it would be a world like Tatooine. 

However, the system lacks similarities to famous fictional examples, and it makes up for its potential to solve some long-standing problems in planetary formation theory. In addition to searching for a potential exomoon around TOI 4633c, scientists will continue to monitor the system closely to see if it remains stable. They can also see how the current known (and theorized) planets fit into existing models of planetary system formation.

This is another feather in the cap of the Planet Hunters TESS citizen science collaboration. There are undoubtedly more strange star systems out there for them to find. If you’re interested in helping them, you can sign up here.

Learn More:
NASA – Discovery Alert: Mini-Neptune in Double Star System is a Planetary Puzzle
Eisner et al. – Planet Hunters TESS. V. A Planetary System Around a Binary Star, Including a Mini-Neptune in the Habitable Zone
UT – Marvel at the Variety of Planets Found by TESS Already
UT – A New Venus-Sized World Found in the Habitable Zone of its Star

Lead Image:
Artist’s depiction of the binary system TOI 4633 and its potentially habitable planet.
Credit – Ed Bell for Simons Foundation

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Categories: Astronomy

Astronomy Generates Mountains of Data. That’s Perfect for AI

Wed, 05/29/2024 - 12:26pm

Consumer-grade AI is finding its way into people’s daily lives with its ability to generate text and images and automate tasks. But astronomers need much more powerful, specialized AI. The vast amounts of observational data generated by modern telescopes and observatories defies astronomers’ efforts to extract all of its meaning.

A team of scientists is developing a new AI for astronomical data called AstroPT. They’ve presented it in a new paper titled “AstroPT: Scaling Large Observation Models for Astronomy.” The paper is available at arxiv.org, and the lead author is Michael J. Smith, a data scientist and astronomer from Aspia Space.

Astronomers are facing a growing deluge of data, which will expand enormously when the Vera Rubin Observatory (VRO) comes online in 2025. The VRO has the world’s largest camera, and each of its images could fill 1500 large-screen TVs. During its ten-year mission, the VRO will generate about 0.5 exabytes of data, which is about 50,000 times more data than is contained in the USA’s Library of Congress.

The VRO’s need for multiple sites to handle all of its data is a testament to the enormous volume of data it will generate. Without effective AI, that data will be stuck in a bottleneck. Image Credit: NOIRLab.

Other telescopes with enormous mirrors are also approaching first light. The Giant Magellan Telescope, the Thirty Meter Telescope, and the European Extremely Large Telescope combined will generate an overwhelming amount of data.

Having data that can’t be processed is the same as not having the data at all. It’s basically inert and has no meaning until it’s processed somehow. “When you have too much data, and you don’t have the technology to process it, it’s like having no data,” said Cecilia Garraffo, a computational astrophysicist at the Harvard-Smithsonian Center for Astrophysics.

This is where AstroPT comes in.

AstroPT stands for Astro Pretrained Transformer, where a transformer is a particular type of AI. Transformers can change or transform an input sequence into an output sequence. AI needs to be trained, and AstroPT has been trained on 8.6 million 512 x 512-pixel images from the DESI Legacy Survey Data Release 8. DESI is the Dark Energy Spectroscopic Instrument. DESI studies the effect of Dark Energy by capturing the optical spectra from tens of millions of galaxies and quasars.

AstroPT and similar AI deal with ‘tokens.’ Tokens are visual elements in a larger image that contain meaning. By breaking images down into tokens, an AI can understand the larger meaning of an image. AstroPT can transform individual tokens into coherent output.

AstroPT has been trained on visual tokens. The idea is to teach the AI to predict the next token. The more thoroughly it’s been trained to do that, the better it will perform.

“We demonstrated that simple generative autoregressive models can learn scientifically useful information when pre-trained on the surrogate task of predicting the next 16 × 16 pixel patch in a sequence of galaxy image patches,” the authors write. In this scheme, each image patch is a token.

This image illustrates how the authors trained AstroPT to predict the next token in a ‘spiralised’ sequence of galaxy image patches. It shows the token feed order. “As the galaxies are in the centre of each postage stamp, this set up allows us to seamlessly pretrain and run inference on differently sized galaxy postage stamps,” the authors explain. Image Credit: Smith et al. 2024.

One of the obstacles to training AI like AstroPT concerns what AI scientists call the ‘token crisis.’ To be effective, AI needs to be trained on a large number of quality tokens. In a 2023 paper, a separate team of researchers explained that a lack of tokens can limit the effectiveness of some AI, such as LLMs or Large Language Models. “State-of-the-art LLMs require vast amounts of internet-scale text data for pre-training,” the wrote. “Unfortunately, … the growth rate of high-quality text data on the internet is much
slower than the growth rate of data required by LLMs.”

AstroPT faces the same problem: a dearth of quality tokens to train on. Like other AI, it uses LOMs or Large Observation Models. The team says their results so far suggest that AstroPT can solve the token crisis by using data from observations. “This is a promising result that suggests that data taken from the observational sciences would complement data from other domains when used to pre-train a single multimodal LOM, and so points towards the use of observational data as one solution to the ‘token crisis’.”

AI developers are eager to find solutions to the token crisis and other AI challenges.

Without better AI, a data processing bottleneck will prevent astronomers and astrophysicists from making discoveries from the vast quantities of data that will soon arrive. Can AstroPT help?

The authors are hoping that it can, but it needs much more development. They say they’re open to collaborating with others to strengthen AstroPT. To aid that, they followed “current leading community models” as closely as possible. They call it an “open to all project.”

“We took these decisions in the belief that collaborative community development paves the fastest route towards realising an open source web-scale large observation model,” they write.

“We warmly invite potential collaborators to join us,” they conclude.

It’ll be interesting to see how AI developers will keep up with the vast amount of astronomical data coming our way.

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Categories: Astronomy

The Sun’s Magnetic Field Might Only Be Skin Deep

Tue, 05/28/2024 - 10:53pm

It’s coming back! Sunspot AR3664 gave us an amazing display of northern lights in mid-May and it’s now rotating back into view. That means another great display if this sunspot continues to flare out. It’s all part of solar maximum—the peak of an 11-year cycle of solar active and quiet times. This cycle is the result of something inside the Sun—the solar dynamo. A team of scientists suggests that this big generator lies not far beneath the solar surface. It creates a magnetic field and spurs flares and sunspots.

For a long time, solar physicists thought the magnetic dynamo was deep inside the Sun. That view may change thanks to work by researchers at MIT, the University of Edinburgh, the University of Colorado, Bates College, Northwestern University, and the University of California. The dynamo may be related to instabilities in what’s called the “near-surface shear layer” in the Sun’s outermost regions. The activities in this layer result in the flares and sunspots we see more of as the Sun nears “solar maximum”. Flares are high-energy outbursts while sunspots are surface features with local magnetic fields. Sunspots are relatively cool regions on the solar surface and occur in 11-year cycles.

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. The loops are magnetic field lines channeling plasma. Credit: NASA/SDO

“The features we see when looking at the Sun, like the corona that many people saw during the recent solar eclipse, sunspots, and solar flares, are all associated with the sun’s magnetic field,” said MIT researcher Keaton Burns. “We show that isolated perturbations near the sun’s surface, far from the deeper layers, can grow over time to potentially produce the magnetic structures we see.”

How is the Sun’s Magnetic Field Connected to Activity?

To understand the magnitude of this finding, let’s look at the structure of the Sun. We all know the Sun is a superheated ball of plasma. So, how does boiling plasma create a magnetic dynamo? “One of the basic ideas for how to start a dynamo is that you need a region where there’s a lot of plasma moving past other plasma and that shearing motion converts kinetic energy into magnetic energy,” Burns explained. “People had thought that the Sun’s magnetic field is created by the motions at the very bottom of the convection zone.”

The interior structure of our Sun. The dynamo generating a magnetic field could lie very close to the solar surface. Credit: Kelvin Ma, via Wikipedia

Of course, pinning down the exact location of the solar dynamo in the upper layers is difficult. Simulations can only go so far, and modeling the plasma flow throughout the entire Sun is a massive computing task. So, Burns and the team decided simulate a smaller piece of the Sun. They studied the stability of plasma flow near the solar surface. That required helioseismology data showing vibrations on the Sun’s surface, which allowed them to determine the average flow of plasma in that region. “If you take a video of a drum and watch how it vibrates in slow motion, you can work out the drumhead’s shape and stiffness from the vibrational modes,” said Burns. “Similarly, we can use vibrations that we see on the solar surface to infer the average structure on the inside.”

Think of the Sun as layered like an onion. Different plasma layers rush past each other as the Sun rotates, according to Burns. “Then we ask: Are there perturbations, or tiny changes in the flow of plasma, that we could superimpose on top of this average structure, that might grow to cause the sun’s magnetic field?”

Computing an Answer

The team developed algorithms that they incorporated into a numerical framework called the Dedalus Project. They looked for self-reinforcing changes in the Sun’s average surface flows. The algorithm discovered new patterns that could grow and result in realistic solar activity. Interestingly, those patterns also match the locations and timescales of sunspots. It turns out that certain changes in the flow of plasma at the very top of the Sun’s surface layers generate magnetic structures. This isn’t a new idea. Burns pointed out that the conditions there resembled the unstable plasma flows in accretion disks around black holes. Accretion disks are massive collections of gas and stellar dust that rotate in towards a black hole. They’re driven by “magnetorotational instability,” which generates turbulence in the flow and causes it to fall inward.

Burns and the team thought this phenomenon at a black hole might also be at work inside our Sun. They suggest that magnetorotational instability in the Sun’s outermost layers could be the first step in generating its magnetic field. “I think this result may be controversial,” he said. “Most of the community has been focused on finding dynamo action deep in the Sun. Now we’re showing there’s a different mechanism that seems to be a better match to observations.”

Implications of the New Model

Not only will the team’s work help solar physicists understand the creation of the magnetic dynamo, but may give them insight into other solar phenomena. In particular, a dynamo in the upper 10 percent of the Sun may explain things like the Maunder Minimum. This was a period between 1645 to 1715 when there were very few sunspots. In some years, observers saw no sunspots at all. In other years, they observed fewer than 20. Astronomers did chart the 11-year sunspot cycle through that time, so the Sun wasn’t entirely inactive.

If the Sun’s magnetic dynamo operates in its outermost layers, the science of solar activity forecasting could get a big boost. Right now, it’s difficult to tell when a flare might break out. Flares and coronal mass ejections like those that contributed to the May 10-11 geomagnetic storm can damage satellites and telecommunications systems here on Earth. In addition, power grids and other technology are at risk. In the long run, however, gaining new understanding of the Sun’s dynamo is a big deal.

“We know the dynamo acts like a giant clock with many complex interacting parts,” says co-author Geoffrey Vasil, a researcher at the University of Edinburgh. “But we don’t know many of the pieces or how they fit together. This new idea of how the solar dynamo starts is essential to understanding and predicting it.”

For More Information

The Origin of the Sun’s Magnetic Field Could Lie Close to Its Surface
The Solar Dynamo Begins Near the Surface

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Categories: Astronomy

Volcanoes Were Erupting on Venus in the 1990s

Tue, 05/28/2024 - 7:48pm

Start talking about Venus and immediately my mind goes to those images from the Venera space probes that visited Venus in the 1970’s. They revealed a world that had been scarred by millennia of volcanic activity yet as far as we could tell those volcanoes were dormant. That is, until just now.  Magellan has been mapping the surface of Venus and between 1990 and 1992 had mapped 98% of the surface. Researchers compared two scans of the same area and discovered that there were fresh outflows of molten rock filling a vent crater! There was active volcanism on Venus. 

Venus is the second planet from the Sun and similar in size to Earth, the similarities end there though. It has a thick atmosphere that is toxic to life as we know it, there is sulphuric acid rain high in the atmosphere and a surface temperature of almost 500 degrees. When the Venera probes visited they measured an atmospheric pressure of around 90 times that at the Earth’s surface. Combined with the other hostile properties of the atmosphere, a human visitor would not survive long. 

Venus

The dense atmosphere of Venus is largely the result of volcanic activity. Over the millennia, there have been extensive volcanic eruptions that pumped carbon dioxide into the atmosphere. The lack of bodies of water on Venus meant the built up carbon dioxide in the atmosphere didn’t get absorbed. In addition to this, the lack of a magnetic field meant the solar wind – the pressure from the Sun – drove away the lighter elements leaving behind the thick, carbon dioxide rich atmosphere we see today. But the volcanoes that drove the atmospheric changes are thought to have been extinct for a long time. 

It’s not just the Venera probes that have been exploring Venus. In 1980, the Magellan spacecraft was launched by NASA to map the surface of the hottest planet in the Solar System. On arrival, it was put into a polar orbit and used radar to penetrate the thick clouds. Back in 2023, a study of some of the Magellan images from the synthetic aperture radar showed changes to a vent near the summit of Maat Mons. It was the first direct evidence of an eruption on the surface of Venus and changes in the lava flows. 

The surface of Venus captured by a Soviet Venera probe. Credit: Russian Academy of Sciences / Ted Stryk

In the latest study that was published in Nature Astronomy, more data from the synthetic aperture radar was studied. The team focussed on Sif Mons and Niobe Planitia and the data that had been collected from both areas in 1990 and again in 1992. The data revealed stronger radar returns in the later set of data suggesting new rock formations from volcanic activity. The team did consider it may have been caused by some other phenomena such as sand dunes or atmospheric effects but altimeter data confirmed the presence of new solidified lava. 

The team were able to use lava flows on Earth as a comparison to help understand the new flows on Venus. They estimated that the new flows are between 3 and 20 metres deep. They could go a step further though and estimated that the eruption at Sif Mons produced about 30 square kilometres of rock which would be enough to fill over 36,000 swimming pools.  The eruption at Niobe Planitia produced even more with an estimated 45 square kilometres of rock..

Studying volcanic activity on Venus helps to understand not just the geological processes but also helps to understand the structure of the interior too. This can help inform the likelihood of habitability for future explorers. None of which would have been possible without the recent volcanic activity to help us probe further the secrets of Venus.

Source: Ongoing Venus Volcanic Activity Discovered With NASA’s Magellan Data

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Categories: Astronomy

Enjoy Five New Images from the Euclid Mission

Tue, 05/28/2024 - 3:59pm

We’re fortunate to live in these times. Multiple space telescopes feed us a rich stream of astounding images that never seems to end. Each one is a portrait of some part of nature’s glory, enriched by the science behind it all. All we have to do is revel in the wonder.

The ESA’s Euclid space telescope is the latest one to enrich our inboxes. It was launched on July 1st, 2023, and delivered its first images in November of that year. Now, we have five new images from Euclid, as well as the first science results from the wide-angle space telescope.

“They give just a hint of what Euclid can do.”

Valeria Pettorino, ESA’s Euclid Project Scientist.

The images demonstrate the telescope’s power and its ability to address some of the deepest questions we have about the Universe. They are also impressive because of their visual richness and because they took only 24 hours of the telescope’s expected six years of observing time.

“Euclid is a unique, ground-breaking mission, and these are the first datasets to be made public – it’s an important milestone,” says Valeria Pettorino, ESA’s Euclid Project Scientist. “The images and associated science findings are impressively diverse in terms of the objects and distances observed. They include a variety of science applications, and yet represent a mere 24 hours of observations. They give just a hint of what Euclid can do. We are looking forward to six more years of data to come!”

The leading image is the most stunning and perhaps the most relatable. It shows Messier 78, aka NGC 2068. It’s a reflection nebula and star-forming region contained in the vast Orion B molecular cloud complex. Euclid used its infrared capabilities to see through the dust that shrouds the star-formation region. It’s given us our most detailed look at the filaments of gas and dust that give the region its ghostly appearance.

Euclid can detect objects that are just a few times more massive than Jupiter, an impressive feat. In its M78 image, it found over 300,000 objects in that mass range.

This zoomed-in portion of Euclid’s M78 image shows the depth the telescope’s images deliver. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE CC BY-SA 3.0 IGO

One of Euclid’s objectives is to study dark matter and how it’s distributed in the Universe. It uses gravitational lensing to probe dark matter, and its image of the Abell 2390 galaxy cluster exhibits the tell-tale curved arcs of light coming from distant background objects created by gravitational lensing. The image also shows more than 50,000 galaxies.

Euclid’s image of the Abell 2390 cluster of galaxies contains over 50,000 galaxies. It also shows the intracluster light that comes from individual stars torn from their galaxies and sitting in intergalactic space. These stars can help astrophysicists determine where dark matter is. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi.
LICENCE: CC BY-SA 3.0 IGO

Most of the stars currently forming in the Universe are forming in spiral galaxies. Euclid captured this image of NGC 6744 as an archetype of that galaxy type. The telescope’s wide-angle lens and depth of field capture the entire galaxy and also small details. It shows lanes of dust that emerge as spurs on the spiral arms.

With this image, astronomers can map individual stars and the gas that feeds their formation. They can also identify globular clusters and new dwarf galaxies. Euclid already found one new dwarf galaxy astronomers have never seen before, which is impressive for a galaxy that’s already been studied so intently.

Euclid’s complete image of NGC 6744 is on the left, and a zoomed-in portion is on the right. NGC 6744 is one of the largest spiral galaxies outside our region of space. The telescope’s detailed image will let astronomers count and map individual stars and the gas that feeds star formation. Star formation is how galaxies evolve, so studying NGC 6744’s star formation activity feeds into a greater understanding of galaxy evolution. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: CC BY-SA 3.0 IGO

Euclid also imaged another galaxy cluster, Abell 2764. This cluster contains hundreds of galaxies within a halo of dark matter. Euclid’s impressive wide-field view comes into play in this image. Not only does it show Abell 2764 in the image’s upper right, but it also shows other clusters that are even more distant, multiple background galaxies, and interacting galaxies with their streams of stars.

In this image, Euclid captured galaxy cluster Abell 2764 and the wider region surrounding it. Abell 2764 is in the upper right corner. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi LICENCE CC BY-SA 3.0 IGO

The image highlights one of Euclid’s other capabilities. The foreground star is in our own galaxy, and when viewed with a telescope, its diffuse light creates a halo that obscures distant objects behind it. Euclid was built to minimize that diffuse halo effect. The disturbance from the star’s diffuse light is minimal, meaning Euclid can see distant background objects near the star’s line of sight.

This pair of zoomed-in images of Abell 2764 shows Euclid’s power. On the left is the foreground star. These stars can create halos of diffuse light that obscure other objects, but Euclid is built to minimize the effect. On the right is a zoom-in of Abell 2764 itself, with multitudes of background galaxies. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: CC BY-SA 3.0 IGO

The final of the five new images is of galaxies in the Dorado Group. Euclid’s image shows signs of galaxies merging. The Dorado Group is a relatively young group, and many of its member galaxies are still forming stars. The image helps astronomers study how galaxies form and evolve inside halos of dark matter.

The Dorado Group is one of the richest galaxy groups in the southern hemisphere. Euclid’s wide and deep images give astronomers their best look at it. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: ESA Standard Licence

A zoomed-in image shows more detail of the main pair of galaxies in the image. Euclid’s unique large field-of-view and high spatial resolution means that for the first time, astronomers can use the same instrument and observations to deeply study tiny objects the size of star clusters, intermediate objects like the central regions of galaxies, and larger features like tidal tails in one large region of the sky.

“The beauty of Euclid is that it covers large regions of the sky in great detail and depth, and can capture a wide range of different objects all in the same image – from faint to bright, from distant to nearby, from the most massive of galaxy clusters to small planets.”

ESA Director of Science, Prof. Carole Mundell

Prior to Euclid, astronomers had to use small chunks of data to painstakingly catalogue globular clusters around galaxies. But Euclid’s wide images capture far more data in a single image, simplifying the task. Globular clusters provide important clues to how galaxies evolve over time.

This zoom-in shows a pair of interacting galaxies in the Dorado Group. Tidal tails of stars are visible as wispy streams near the right and bottom right of the right-side galaxy. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi. LICENCE: ESA Standard Licence

Euclid’s mission is only starting. The telescope’s images so far have no equivalent, and there’s much more to come. Euclid hasn’t even begun its main survey yet. That survey will comprise both a wide survey covering about 15,000 square degrees of the sky and a deep survey covering about 50 square degrees.

“It’s no exaggeration to say that the results we’re seeing from Euclid are unprecedented,” says ESA Director of Science, Prof. Carole Mundell. “Euclid’s first images, published in November, clearly illustrated the telescope’s vast potential to explore the dark Universe, and this second batch is no different.”

“The beauty of Euclid is that it covers large regions of the sky in great detail and depth, and can capture a wide range of different objects all in the same image – from faint to bright, from distant to nearby, from the most massive of galaxy clusters to small planets,” said Mundell. “We get both a very detailed and very wide view all at once. This amazing versatility has resulted in numerous new science results that, when combined with the results from Euclid’s surveying over the coming years, will significantly alter our understanding of the Universe.”

The scientific papers released with these images are available here.

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Categories: Astronomy