Universe Today

Planet Earth is in for some amazing geomagnetic storms in the next year or so. That’s because it’s in a period of peak activity called “solar maximum” (solar max, for short). But, what happens at other planets, especially Mars, during this time? Mars mission scientists got a sneak peek at the effect of a major solar storm thanks to one hitting the Red Planet on May 20th, 2024.

During that event, the Curiosity Mars rover’s Radiation Assessment Detector (RAD) measured a very sharp increase in radiation during the solar storm. At the same time, the navigation camera captured views of a wind gust stirring up surface dust. The radiation count was the highest the instrument has seen since the rover landed on Mars. In space, the Mars Odyssey orbiter’s star camera also experienced a shower of solar particles. The bombardment knocked the camera out for a short time. During its recovery time, the spacecraft continued collecting data. That included information about the x-rays, gamma rays, and other charged particles streaming from the Sun.

NASA’s MAVEN spacecraft also collected data about the bombardment from the May 20th event. “This was the largest solar energetic particle event that MAVEN has ever seen,” said MAVEN Space Weather Lead, Christina Lee of the University of California, Berkeley’s Space Sciences Laboratory. “There have been several solar events in past weeks, so we were seeing wave after wave of particles hitting Mars.”

The purple color in this video shows auroras on Mars’ nightside. The ultraviolet instrument aboard NASA’s MAVEN orbiter detected them between May 14 and 20, 2024. The brighter the purple, the more auroras that were present.  Credit: NASA/University of Colorado/LASP What Protects Planets from the Solar Storm?

There’s not much we as a species can do to protect our planet from a solar storm. However, we’re lucky—we have a strong magnetic field to ward off the worst solar outbursts. Mars is not so lucky. It doesn’t have as much of a magnetic field to ward off the deadly radiation. Space weather experts estimated that if someone had been standing on the Martian surface during that storm, they would have been irradiated with the equivalent of 30 chest X-rays in just a short time.

That storm, and others have sparked auroras on Mars (as well as on Earth). A storm earlier in May sparked off major auroral displays on Earth on May 10-11, but otherwise didn’t severely damage any vital systems. Solar storms, however, do offer a good chance for scientists to track the Sun’s outbursts as they rampage across the Solar System. The data they get gives more insight into solar activity. However, the data from the Mars missions also provides a chilling look at just what kind of risky environment Mars is for future explorers.

Sheltering from the Solar Storm on Mars

Here on Earth, if we have plenty of notice of a solar outburst, people can get ready for the inevitable damage a solar storm can cause. For example, satellite operators can prepare their assets to protect them. NASA can advise astronauts in space to take shelter and other precautions. Ground-based power and telecommunications operators have plans in place to protect their systems from the tremendously strong ground currents that get stirred up by solar storms.

But, what if you’re on your way to Mars when a storm hits? Or, you’re actually ON Mars? Those questions occupy a lot of study time at NASA and other space agencies. People in space, whether orbiting Earth or en route to the Moon or Mars can take shelter inside their craft. In those cases, they have to depend on hardened shelters to keep them safe. But, on Mars, things are different. There’s no strong magnetic field to ward off the strong particles from the Sun. Inhabitants will have to take shelter, according to Don Hassler of Southwest Research Institute’s Solar System Science and Exploration Division.

“Cliffsides or lava tubes would provide additional shielding for an astronaut from such an event. In Mars orbit or deep space, the dose rate would be significantly more,” Hassler said.“I wouldn’t be surprised if this active region on the Sun continues to erupt, meaning even more solar storms at both Earth and Mars over the coming weeks.”

What Happened on May 20th?

The storm that Curiosity recorded began with an X12-class solar flare. That’s one of the strongest solar flares recorded and, if it had been aimed at Earth, could have caused some major damage. As it turns out, Mars was in the pathway of that flare and a subsequent coronal mass ejection. It launched a cloud of charged particles through space. When the outburst from the flare and the CME arrived at Mars, it triggered auroral displays on the Martian night side. At the same time, the outbursts showered the surface with charged particles. If someone had been on Mars and working outside a shelter, they would have been dosed with the equivalent of 30 chest X-rays. That’s not a deadly exposure, but over time if someone experienced many such events, the damage to their body would add up.

Luckily, the storm did no damage to Curiosity or any of the spacecraft at Mars. But, that won’t always be the case, and mission planners can use the data from this storm and others to figure out how best to protect future explorers.

A NASA video about how a solar storm affected Mars. For More Information

NASA Watches Mars Light Up During Epic Solar Storm
NASA Curiosity Mars Mission

The post A Recent Solar Storm Even Had an Impact on Mars appeared first on Universe Today.

Scientists scour the Earth and the sky for clues to our planet’s climate history. Powerful and sustained volcanic eruptions can alter the climate for long periods of time, and the Sun’s output can shift Earth’s climate over millions of years.

But what about interstellar hydrogen clouds? Can these regions of gas and dust change Earth’s climate when the planet encounters them?

Interstellar clouds aren’t all the same. Some are diffuse, while some are much denser. New research in Nature Astronomy says that our Solar System may have passed through one of the dense clouds two or three million years ago. The effect could’ve altered the chemistry of Earth’s atmosphere, affecting cloud formation and the climate.

The research is “A possible direct exposure of the Earth to the cold dense interstellar medium 2–3 Myr ago.” The lead author is Merav Opher from the Radcliffe Institute for Advanced Study at Harvard University and the Astronomy Department at Boston University.

“Our results open a new window into the relationship between the evolution of life on Earth and our cosmic neighborhood.”

Avi Loeb, co-author, Harvard University’s Institute for Theory and Computation

The Sun is moving through a large cavity in the interstellar medium (ISM) called the Local Bubble. Inside the LB, the Sun’s solar output creates a cocoon called the heliosphere. It shields the Solar System from cosmic radiation.

Inside the LB, there’s more than just the Sun. It also contains other stars, and the Local Interstellar Cloud (LIC). The Sun has been moving through the LIC and will leave it in a few thousand years. The LIC is not very dense.

But in the last few million years, as the Sun has traversed the Local Bubble, it’s encountered clouds that are much denser than the LIC. The researchers examined the effect these encounters had on the Sun’s ability to carve out a cocoon for the Solar System and what effect this had on Earth.

“Stars move, and now this paper is showing not only that they move, but they encounter drastic changes.”

Merav Opher, Professor of Astronomy, BU College of Arts & Sciences

“Here we show that in the ISM that the Sun has traversed for the last couple of million years, there are cold, compact clouds that could have drastically affected the heliosphere. We explore a scenario whereby the Solar System went through a cold gas cloud a few million years ago,” Opher and her colleagues write.

Most of what the Sun travels through is thin ISM. The Sun constantly moves through the thin ISM with no effect. “These clouds are plentiful around the Sun but have too low a density to contract the heliosphere to distances <130au,” the authors explain. For comparison, the Kuiper Belt spans from 30 to 55 AU away from the Sun.

However, the denser clouds in the ISM are dense enough to dramatically affect the protective heliosphere. “The ISM in the vicinity of the Solar System also harbours a few, rare, dense, cold clouds that are called the Local Ribbon of Cold Clouds,” they write.

One of the clouds in that ribbon is called the Local Leo Cold Cloud (LLCC). It’s one of the largest clouds in the ribbon, and astronomers have studied it extensively. They know its density and its temperature. Researchers haven’t paid as much attention to the other clouds in the ribbon, but they expect them to be similar.

The authors of this paper say that there’s a small chance, about 1.3%, that the Sun passed through the tail of the LLCC. “We name that portion the Local Lynx of Cold Clouds (LxCCs). The LxCCs represent nearly half of all the mass of the LRCC and are more massive than the more well-studied LLCC,” they write.

This diagram from the research shows how the Sun may have passed through the tail of the LRCC about 2 to 3 million years ago. Image Credit: Opher et al. 2024.

There are questions about the nature of these clouds in the past. “Note that these clouds are anomalous and unexplained structures in the ISM, and their origin and physics are not well understood,” the authors write. Their work is based on the assumption that they haven’t changed substantially in the 2 million years since the purported encounter. “We have assumed here that these clouds have not undergone any substantial change over the last 2~Myr, though future work may provide more insight into their evolution.”

The researchers used simulations to study the dense cloud’s effect on the heliosphere and, by extension, our planet. They say that the cloud’s hydrogen density pushed back on the Sun, shrinking the heliosphere smaller than the Earth’s orbit around the Sun. It brought both the Sun and the Moon into contact with the dense, cold ISM. “Such an event may have had a dramatic impact on the Earth’s climate,” they explain.

These images from the simulations show the heliosphere being distorted by passage through the tail of the Local Lynx of Cold Clouds. a is a side view, and b is a top view. The red circle shows Earth’s orbit around the Sun. The simulations show that for a period of time, Earth was outside of the Sun’s protective heliosphere. Image Credit: Opher et al. 2024.

The encounter is supported by the presence of the radioisotope 60Fe on Earth. 60Fe is predominantly produced in supernovae and has a half-life of 2.6 million years. Previous research linked the 60Fe to a supernova explosion, where it became entrenched in dust grains and then delivered to Earth. It’s also present on the Moon. 244Pu was delivered at the same time, also in supernovae ejecta.

While there’s a lot of uncertainty, the researchers say the deposition of 60Fe on Earth lines up with our Solar System’s hypothetical passage through a dense cloud that compressed the protective heliosphere, allowing the isotopes to reach Earth. “Our proposed scenario agrees with the geological evidence from 60Fe and 244Pu isotopes that Earth was in direct contact with the ISM during that period,” they write.

But if a supernova delivered the radioisotopes, it would have to have been pretty close, and other evidence discounts the supernova source. “A close supernova explosion contradicts the recent model of the Local Bubble formation,” the authors explain. “The scenario does not require the absorption of 60Fe and 244Pu into dust particles that deliver them specifically to Earth, like the scenario with nearby supernova explosions.”

The question at the heart of this issue is, how did this affect Earth?

An in-depth study of the consequences is outside the scope of this research. The team did comment on some possibilities, while also cautioning that very little research has been done on this matter.

“Very few works have investigated the climatic effects of such encounters quantitatively in the context of encounters with dense giant molecular clouds. Some argue that such high densities would deplete the ozone in the mid-atmosphere (50–100?km) and eventually cool the Earth,” they write.

It’s a leap, but some research suggests that this cooling could have contributed to the rise of our species. “The hypothesis is that the emergence of our species, Homo sapiens, was shaped by the need to adapt to climate change. With the shrinkage of the heliosphere, the Earth was exposed directly to the ISM,” they write.

In their conclusion, they remind us that the probability that this encounter took place is low. But not zero.

“Stars move, and now this paper is showing not only that they move, but they encounter drastic changes,” said Opher, a BU College of Arts & Sciences professor of astronomy and member of the University’s Center for Space Physics.

“Although the coincidence of the Sun’s past motion with these rare clouds is truly remarkable, the turbulent nature of the ISM and the small current angular size of these clouds mean that the past location error ellipse is much larger than the clouds and, absent any other information, the probability of their encounter is measured to be low,” they write in their conclusion. It’s up to future work to dig more deeply into the matter.

Even if this particular encounter may not have happened, the research is still fascinating. There appear to be a bewildering number of variables that led to us, and it’s not a stretch to imagine that passing through dense clouds in the ISM played some role at some point.

“Only rarely does our cosmic neighborhood beyond the solar system affect life on Earth,” said Avi Loeb, director of Harvard University’s Institute for Theory and Computation and coauthor on the paper. “It is exciting to discover that our passage through dense clouds a few million years ago could have exposed the Earth to a much larger flux of cosmic rays and hydrogen atoms. Our results open a new window into the relationship between the evolution of life on Earth and our cosmic neighborhood.”

“We hope that our present work will incentivize future works detailing the climate effects due to an encounter of the heliosphere with the LRCC and possible consequences for evolution on Earth,” the authors conclude.

The post Was Earth’s Climate Affected by Interstellar Clouds? appeared first on Universe Today.

The James Webb Space Telescope (JWST) continues to make amazing discoveries. This time in the constellation of Pictor where, in the Beta Pictoris system a massive collision of asteroids. The system is young and only just beginning its evolutionary journey with planets only now starting to form. Just recently, observations from JWST have shown significant energy changes emitted by dust grains in the system compared to observations made 20 years ago. Dust production was thought to be ongoing but the results showed the data captured 20 years ago may have been a one-off event that has since faded suggesting perhaps, an asteroid strike!

Beta Pictoris is a young star located 63 light years away in the constellation Pictor. It has become well known for its fabulous circumstellar disk of gas and dust out of which a new system of planets is forming. It has been the subject of many a study because not only does it provide an ideal opportunity to study planetary formation but one of those planets Beta Pictoris b has already been detected. 

Beta Pictoris is located about 60 light-years away towards the constellation of Pictor (the Painter’s Easel) and is one of the best-known examples of a star surrounded by a dusty debris disc. Earlier observations showed a warp of the disc, a secondary inclined disc and comets falling onto the star, all indirect, but tell-tale signs that strongly suggested the presence of a massive planet. Observations done with the NACO instrument on ESO’s Very Large Telescope in 2003, 2008 and 2009, have proven the presence of a planet around Beta Pictoris. It is located at a distance between 8 and 15 times the Earth-Sun separation — or Astronomical Units — which is about the distance Saturn is from the Sun. The planet has a mass of about nine Jupiter masses and the right mass and location to explain the observed warp in the inner parts of the disc. This image, based on data from the Digitized Sky Survey 2, shows a region of approximately 1.7 x 2.3 degrees around Beta Pictoris. Credit: ESO/Sky Survey II

Wind the clock back 20 years and the Spitzer infra-red observatory was observing Beta Pictoris. It was looking for heat being emitted by crystalline silicate minerals which are often found around young stars and on celestial bodies. Back in 2004-2005 no traces were seen suggesting a collision occurred among asteroids destroying them and turning their bodies into find dust particles, smaller even than grains of sand and even powdered sugar. 

Radiation was detected at the 17 and 24 micron wavelengths by Spitzer, the result of significant amounts of dust. Using JWST, the team studied radiation from dust particles around Beta Pictoris and were able to compare with these Spitzer findings. They were able to identify the composition and size of particles in the same area around Beta Pictoris  that was studied by Spitzer. They found a significant reduction in radiation at the same wavelengths from 20 years ago. 

The Spitzer Space Telescope observatory trails behind Earth as it orbits the Sun. Credit: NASA/JPL-Caltech

According to Christine Chen, lead astronomer from the John Hopkins University ‘With Webb’s new data, the explanation we have is that, in fact, we witnessed the aftermath of an infrequent, cataclysmic event between large asteroid-sized bodies, marking a complete change in our understanding of this star system.’

By tracking the distribution of particles across the circumstellar disk, the team found that the dust seems to have been dispersed outward by radiation from the hot young star. Previously with observations from Spitzer, dust surrounded the star which was heated up by its thermal radiation making it a strong thermal emitter. This is no longer the case as that dust has moved, cooled and no longer emits those thermal features. 

The discovery has adjusted our view of planetary system formation. Previous theories suggested that small bodies would accumulate and replenish the dust steadily over time. Instead, JWST has shown that the dust is not always replenished with time but that it takes a cataclysmic asteroid impact to seed new planetary systems with new dust. The team estimate the asteroid that was pulverised was about 100,000 times the size of the asteroid that killed the dinosaurs!

Source : WEBB TELESCOPE REVEALS ASTEROID COLLISION IN NEIGHBORING STAR SYSTEM

The post Webb Sees Asteroids Collide in Another Star System appeared first on Universe Today.

Dark Matter is Nature’s poltergeist. We can see its effects, but we can’t see it, and we don’t know what it is. It’s as if Nature is playing tricks on us, hiding most of its mass and confounding our efforts to determine what it is.

It’s all part of the Universe’s “missing mass” problem. Actually, it’s our problem. The Universe is what it is. It’s our understanding of the Universe, mass, and gravity that’s the problem. And a solution is proving to be elusive.

Whatever the missing mass is or whatever causes the effects we observe, we have a placeholder name for it: dark matter. And it makes up 85% of the matter in the Universe.

Could dark matter be primordial black holes? Could it be axions? How about WIMPS? Are dark photons its force carrier? There’s lots of theoretical thought but no conclusion.

New research in the Monthly Notices of the Royal Astronomical Society says that our hunt for dark matter may be off-track. Instead of looking for a type of particle, the solution might lie in a type of topological defect found throughout the Universe that has its roots in the Universe’s early stages.

The new research is in a paper titled “The binding of cosmological structures by massless topological defects.” The author is Richard Lieu, a distinguished professor of physics and astronomy at the University of Alabama at Huntsville.

“There is then no need to perpetuate this seemingly endless search for dark matter.”

Dr. Richard Lieu, Professor, University of Alabama, Huntsville

As the paper’s title makes clear, dark matter has a binding effect on structures like galaxies. Astronomers know that galaxies don’t have enough measurable mass to hold themselves together. By measuring the mass of the stars and gas in galaxies, it became clear that the visible components of the galaxies don’t provide enough mass to hold themselves together. They should simply dissipate into their constituent stars and clouds of gas.

But galaxies don’t dissipate, and scientists have concluded that something is missing. Professor Lieu has another idea.

“My own inspiration came from my pursuit for another solution to the gravitational field equations of general relativity — the simplified version of which, applicable to the conditions of galaxies and clusters of galaxies, is known as the Poisson equation — which gives a finite gravitation force in the absence of any detectable mass,” said Lieu. “This initiative is in turn driven by my frustration with the status quo, namely the notion of dark matter’s existence despite the lack of any direct evidence for a whole century.”

An entire century is a long time in the age of modern science. It’s not surprising that Nature has the power to confound us, but it is somewhat surprising that very little progress has been made on the problem. Scientists have made great progress in understanding how dark matter influences the Universe’s large-scale structure, an impressive feat, but haven’t figured out what it is.

“The nature of dark matter (DM), defined specifically in this letter as an unknown component of the cosmic substratum responsible for the extra gravitational field that binds galaxies and clusters of galaxies, has been an enigma for more than a century,” Dr. Lieu writes in his paper.

Lieu’s work leans on phase transitions in the Universe. These are episodes when the state of matter in the Universe changes. Not locally but across the entire cosmos. One example is when the Universe cooled enough to allow the strong force to bind quarks into protons and neutrons.

Dr. Lieu contends that topological defects could have formed during one of these phase transitions. These defects can take the shape of shell-like compact regions where matter density is much higher. When arranged in concentric rings, these defects behave like gravity but don’t have mass.

“It is unclear presently what precise form of phase transition in the universe could give rise to topological defects of this sort,” Lieu says. “Topological effects are very compact regions of space with a very high density of matter, usually in the form of linear structures known as cosmic strings, although 2-D structures such as spherical shells are also possible. The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers — which is all one could measure, mass-wise — is exactly zero, but when a star lies on this shell it experiences a large gravitational force pulling it towards the center of the shell.”

So, despite our inability to measure the mass, it’s there, and other objects respond to it. Mass warps space-time and affects even massless photons. That fact underlies our ability to use gravitational lensing. We use the mass of galaxy clusters in gravitational lensing. A set of spherical shells, as Lieu talks about, could cause the same effect.

This illustration shows the gravitational lensing phenomenon. Astronomers use it to study very distant and very faint objects. Note that the scale has been greatly exaggerated in this diagram. In reality, the distant galaxy is much further away and much smaller. Image Credit: NASA, ESA & L. Calcada

“Gravitational bending of light by a set of concentric singular shells comprising a galaxy or cluster is due to a ray of light being deflected slightly inwards — that is, towards the center of the large-scale structure, or the set of shells — as it passes through one shell,” Lieu notes. “The sum total effect of passage through many shells is a finite and measurable total deflection which mimics the presence of a large amount of dark matter in much the same way as the velocity of stellar orbits.”

Since astronomers measure galaxy and galaxy cluster masses by measuring the light they deflect and the way they affect the orbit of stars, astronomers could be measuring topological defects rather than particles that comprise dark matter.

“Both the deflection of light and stellar orbital velocities is the only means by which one gauges the strength of the gravitational field in a large-scale structure, be it a galaxy or a cluster of galaxies,” Dr. Lieu says. “The contention of my paper is that at least the shells it posits are massless. There is then no need to perpetuate this seemingly endless search for dark matter.”

In 2022, researchers discovered a giant arc in the sky. It spans 1 Gigaparsec and is nearly symmetrical. It’s one of several large-scale structures that seems to go against the Standard Model and the Cosmological Principle it’s based on.

These are three separate data images of the Giant Arc discovered in 2022. The paper provides details. Image Credit: Lopez et al. 2022, 10.1093/mnras/stac2204

“The observation of giant arcs and rings could lend further support to the proposed alternative to the DM model,” Lieu writes in his paper. He also points out that the shells he proposes needn’t be a complete sphere.

If these shells exist, their alignment would also govern the formation and shape of galaxies and clusters. Future research will determine exactly how these shells form. “This paper does not attempt to tackle the problem of structure formation,” Lieu says. In fact, Lieu acknowledges that there’s currently no way to even observe how they might form.

“A contentious point is whether the shells were initially planes or even straight strings, but angular momentum winds them up. There is also the question of how to confirm or refute the proposed shells by dedicated observations,” Lieu says.

An experienced scientist, Lieu knows the limits of what he’s proposing.

“Of course, the availability of a second solution, even if it is highly suggestive, is not by itself sufficient to discredit the dark matter hypothesis — it could be an interesting mathematical exercise at best,” Lieu concludes. “But it is the first proof that gravity can exist without mass.”

The post If Gravity Can Exist Without Mass, That Could Explain Dark Matter appeared first on Universe Today.

Observing the earliest stars is one of the holy Grails of astronomy. Now, a team at the University of Hong Kong led by astronomer Jane Lixin Dai is proposing a new method for detecting them. If it works, the approach promises to open a window on the origin of the cosmos itself.

The earliest stars in the Universe formed very soon after the Big Bang. Astronomers call them “Population III” (or Pop III) stars. They’re different from the Sun and other stars in the modern cosmos for a variety of reasons. They formed mainly from the hydrogen and helium in the newborn cosmos. From there, they grew to outrageous sizes and masses very quickly. That growth had a price. Those stars had very short lives because they blew through their core fuels very quickly. However, fusion at their cores and the circumstances of their deaths created the first elements heavier than hydrogen and helium. Those new elements seeded the next generations of stars.

Population III stars were the Universe’s first stars. They were extremely massive, luminous stars, and many of them exploded as supernovae. Image Credit: DALL-E

So, why can’t we detect these early stellar behemoths? For one thing, they existed too far away, too early in history, and their light is very faint. That’s not to say they are undetectable. Astronomers just need advanced methods and technology to spot them.

How to “See” the First Stars

Professor Dai’s team just published a study that suggests a connection between these first stars and nearby black holes. In short, they looked at what happens when a Pop III star interacts with a black hole. Essentially, it gets torn to shreds and gobbled up. For example, the supermassive one at the heart of our Milky Way Galaxy—called Sagittarius A*— does this. It has a regular habit of ripping apart stars that wander too close. When such a tidal disruption event (TDE) happens, it releases huge amounts of radiation. If the same thing happens in another galaxy—no matter how far away—the light from the event is detectable. As it turns out these tidal disruption event flares have interesting and unique properties used to infer the existence of the ancient Pop III stars.

The alien star S0-6 is spiraling toward Sagittarius A*, the Milky Way’s central supermassive black hole. S0-6 likely came from another galaxy and it may get gobbled up or torn up by interactions with the supermassive black hole. Courtesy: Miyagi University of Education/NAOJ.

“As the energetic photons travel from a very faraway distance, the timescale of the flare will be stretched due to the expansion of the Universe. These TDE flares will rise and decay over a very long period of time, which sets them apart from the TDEs of solar-type stars in the nearby Universe,” said Dai.

In addition, the expansion of the Universe stretches the wavelengths of light from the flares, according to Dai’s colleague, Rudrani Kar Chowdhury. “The optical and ultraviolet light emitted by the TDE will be transferred to infrared emissions when reaching the Earth,” Chowdhury said. Those emissions are exactly the kind of light new generations of telescopes are built to observe.

Searching for First Stars with Advanced Telescopes

This detection method is right up the alley of the JWST and the upcoming Nancy Grace Roman telescopes. Both are optimized to sense dim, distant objects via infrared wavelengths. They should be able to search out the stretched light from those long-gone Pop III stars unfortunate enough to encounter a black hole. In particular, the Roman telescope will use its wide-field instrument to gather the faint infrared light from stars born at the earliest epochs of cosmic time.

Artist’s impression of the Nancy Grace Roman space telescope (formerly WFIRST). Credit: NASA/GSFC

Astronomers generally accept that these first stars formed perhaps as early as a hundred million years after the Big Bang. That’s when overly dense regions filled with hydrogen and helium began to experience gravitational collapse. The stars that formed in those first birth crèches were purely hydrogen and helium—in other words, they were “metal-free”. They lived perhaps a few million years before exploding as cataclysmic supernovae. (By comparison, the Sun has existed for some 4.5 billion years and has another few billion years left before it becomes a red giant and then a white dwarf.) The heavier elements created inside those first stars got blasted out to space, enriching the nearby molecular clouds with infusions of carbon, oxygen, nitrogen, and other elements. Some of the largest first stars could have collapsed directly to form black holes.

Finding these first stars and their emitted light (particularly from possible interactions with early black holes) will give astronomers amazing insight into conditions in the early Universe. Even though those stars are long gone, JWST, Roman, and other telescopes can look back in time and see their dim, infrared light. If Dai’s method works, those telescopes could be responsible for the discovery of tens of Pop III stars each year.

For More Information

HKU Astrophysicists Discover a Novel Method for Hunting the First Stars
Detecting Population III Stars through Tidal Disruption Events in the Era of JWST and RomanNancy Grace Roman Space Telescope

The post A New Way to Search for the First Stars in the Universe appeared first on Universe Today.

There are plenty of crazy ideas for missions in the space exploration community. Some are just better funded than others. One of the early pathways to funding the crazy ideas is NASA’s Institute for Advanced Concepts. In 2017 and again in 2021, it funded a mission study of what most space enthusiasts would consider only a modestly ambitious goal but what those outside the community might consider outlandish—landing on Pluto.

Two major questions stand out in the mission design: How would a probe arriving at Pluto slow down, and what kind of lander would be useful on Pluto itself? The answer to the first is one that is becoming increasingly common on planetary exploration missions: aerobraking.

Pluto has an atmosphere, albeit sparse, as confirmed by the New Horizons mission that whizzed past in 2015. One advantage of the minor planet’s relatively weak gravity is that its low-density atmosphere is almost eight times larger than Earth’s, providing a much bigger target for a fast incoming aerobraking craft to aim for.

Fraser discusses future missions to Pluto.

Much of the NIAC Phase I project was focused on the details of that aerobraking system, called the Enveloping Aerodynamic Decelerator (EAD). Combined with a lander, that system makes up the “Entrycraft” that the mission is designed around. Ostensibly, it could alternatively contain an orbiter, and there are plenty of other missions discussing how to insert an orbiter around Pluto. Hence, the main thrust of this paper is to focus on a lander.

After aerobraking and slowing down to a few tens of meters a second, from 14 km/s during its interplanetary cruise phase, the mission would drop its lander payload, then rest on the surface, only to rise again under its own power. The answer to the second question of what kind of lander would be useful on Pluto is – a hopper.

Hoppers have become increasingly popular as an exploration tool everywhere, from the Moon to asteroids. Some apparent advantages would include visiting a wide array of interesting scientific sites and not having to navigate tricky land-based obstacles. Ingenuity, the helicopter that accompanied Perseverance paved the way for the idea, but in other words, the atmosphere isn’t dense enough to support a helicopter. So why not use the current favorite method of almost all spacecraft – rockets?

Fraser discusses the results from New Horizons.

A hopper would fire its onboard thrusters to reach the area on Pluto’s surface and then land elsewhere. It could then do some science at its new locale before taking off and doing so again somewhere else. The NIAC Phase I Final Report describes five main scientific objectives of the mission, including understanding the surface geomorphology and running some in-situ chemical analysis. A hopper structure would enable those goals much better than a traditional rover at a relatively low weight cost since Pluto’s gravity is so weak.

Other objectives of the report include mathematical calculations of the trajectory, including the aerobraking itself and the stress and strain it would have on the materials used in the system. The authors, who primarily work for Global Aerospace Corporation and ILC Dover, two private companies, also updated the atmospheric models of Pluto with new New Horizons data, which they then fed into the aerobraking model they used. Designing the lander/hopper, integrating all the scientific and navigation components, and estimating their weights were also part of Phase I.

The original launch window for the mission was planned as 2029 back in 2018, though now, despite receiving a Phase II NIAC grant in 2021, that launch window seems wildly optimistic. Since the mission would require a gravity assist from Jupiter, the next potential launch window would be 2042, with a lander finally reaching the surface of Pluto in the 2050s. That later launch window is likely the only feasible one for the mission, so we might have to wait almost 30 years to see if it will come to fruition. Sometimes crazy ideas take patience – we’ll see if the mission team has enough of that to push it onto the surface of one of the most interesting minor planets in the solar system.

Learn More:
B. Goldman – Pluto Hop, Skip, and Jump
UT – NASA is Now Considering a Pluto Orbiter Mission
UT – Should We Send Humans to Pluto?
UT – New Horizons Team Pieces Together the Best Images They Have of Pluto’s Far Side

Lead Image:
Artist’s depiction of the Pluto Lander mission design.
Credit- B. Goldman / Global Aerospace Corporation

The post Landing on Pluto May Only Be A Hop Skip and Jump Away appeared first on Universe Today.

The Milky Way is only as massive as it is because of collisions and mergers with other galaxies. This is a messy process, and we see the same thing happening with other galaxies throughout the Universe. Currently, we see the Milky Way nibbling at its two satellite galaxies, the Large and Small Magellanic Clouds. Their fate is likely sealed, and they’ll be absorbed into our galaxy.

Researchers thought the last major merger occurred in the Milky Way’s distant past, between 8 and 11 billion years ago. But new research amplifies the idea that it was much more recent: less than 3 billion years ago.

This new insight into our galactic history comes from the ESA’s Gaia mission. Launched in 2013, Gaia is busily mapping 1 billion astronomical objects, mostly stars. It measures them repeatedly, establishing accurate measurements of their positions and motions.

A new paper published in the Monthly Notices of the Royal Astronomical Society presents the findings. It’s titled “The Debris of the ‘Last Major Merger’ is Dynamically Young.” The lead author is Thomas Donlon, a post-doctoral researcher in Physics and Astronomy at the University of Alabama, Huntsville. Donlon has been studying mergers in the Milky Way for several years and has published other work on the matter.

Each time another galaxy collides and merges with the Milky Way, it leaves wrinkles. ‘Wrinkles’ obviously isn’t a scientific term. It’s an umbrella term for several types of morphologies, including phase space folds, caustics, chevrons, and shells. These wrinkles move through different groups of stars within the Milky Way, affecting how the stars move through space. By measuring the positions and velocities of these stars with great precision, Gaia can detect the wrinkles, the imprint of the last major merger.

“We get wrinklier as we age, but our work reveals that the opposite is true for the Milky Way. It’s a sort of cosmic Benjamin Button, getting less wrinkly over time,” said lead author Donlon in a press release. “By looking at how these wrinkles dissipate over time, we can trace when the Milky Way experienced its last big crash—and it turns out this happened billions of years later than we thought.”

The effort to understand the Milky Way’s (MW) last major merger involves different pieces of evidence. One of the pieces of evidence, along with wrinkles, is an Fe/H-rich region where stars follow a highly eccentric orbit. A star’s Fe/H ratio is a chemical fingerprint, and when astronomers find a group of stars with the same fingerprint and the same orbits, it’s evidence of a common origin. This group of stars is sometimes called ‘the Splash.’ The stars in the Splash may have originated in a Fe/H-rich progenitor. They have odd orbits that stand out from their surroundings. Astronomers think they were heated and their orbits altered as a by-product of the merger.

There are two competing explanations for all of the merger evidence.

One says that a progenitor dwarf galaxy named Gaia Sausage/Enceladus (GSE) collided with the MW proto-disk between 8 and 11 billion years ago. The other explanation is that an event called the Virgo Radial Merger (VRM) is responsible for the stars in the inner halo. That collision occurred much more recently, less than 3 billion years ago.

This is a Hubble Space Telescope image of the globular cluster NGC 2808. It might be the old core of the Gaia Sausage. Image Credit: By NASA, ESA, A. Sarajedini (University of Florida) and G. Piotto (University of Padua (Padova)) – http://hubblesite.org/newscenter/archive/releases/2007/2007/18/image/a/ (direct link), Public Domain, https://commons.wikimedia.org/w/index.php?curid=2371715

“These two scenarios make different predictions about observable structure in local phase space because the morphology of debris depends on how long it has had to phase mix,” the authors explain in their paper.

The wrinkles in the MW were first identified in Gaia data in 2018 and presented in this paper. “We have observed shapes with different morphologies, such as a spiral similar to a snail’s shell. The existence of these substructures has been observed for the first time thanks to the unprecedented precision of the data brought by Gaia satellite, from the European Space Agency (ESA)”, said Teresa Antoja, the study’s first author, in 2018.

This AI-generated image illustrates the MW’s ‘wrinkles’ from the last major merger event. Image Credit: University of Barcelona.

But Gaia has released more data since 2018, and it supports the more recent merger scenario, the Virgo Radial Merger. That data shows that the wrinkles are much more prevalent than the earlier data and the studies based on it suggest.

“For the wrinkles of stars to be as clear as they appear in Gaia data, they must have joined us less than 3 billion years ago—at least 5 billion years later than was previously thought,” said co-author Heidi Jo Newberg, from the Rensselaer Polytechnic Institute. If the wrinkles were much older and conformed to the GSE merger scenario, they’d be more difficult to discern.

“New wrinkles of stars form each time the stars swing back and forth through the center of the Milky Way. If they’d joined us 8 billion years ago, there would be so many wrinkles right next to each other that we would no longer see them as separate features,” Newberg said.

This doesn’t mean there’s no evidence for the more ancient GSE merger. Some of the stars that hint at the ancient merger may be from the more recent VRM merger, and some may still be associated with the GSE merger. It’s challenging to figure out, and simulations play a large role. The researchers in previous work and in this work ran multiple simulations to see how they matched the evidence. “Our goal is to determine the time that has passed since the progenitor of the local phase-space folds collided with the MW disc,” the authors write in their paper.

“We can see how the shapes and number of wrinkles change over time using these simulated mergers. This lets us pinpoint the exact time when the simulation best matches what we see in real Gaia data of the Milky Way today—a method we used in this new study too,” said Thomas.

“By doing this, we found that the wrinkles were likely caused by a dwarf galaxy colliding with the Milky Way around 2.7 billion years ago. We named this event the Virgo Radial Merger.” Those results and the name come from a previous study from 2019.

As Gaia delivers more data with each release, astronomers are getting a better look at the evidence of mergers. It’s becoming clear that the MW has a complex history.

The VRM likely involved more than one entity. It could have brought a whole group of dwarf galaxies and star clusters into the MW at around the same time. As astronomers research the MW’s merger history in greater detail, they hope to determine which of these objects are from the more recent VRM and which are from the ancient GSE.

“The Milky Way’s history is constantly being rewritten at the moment, in no small part thanks to new data from Gaia,” adds Thomas. “Our picture of the Milky Way’s past has changed dramatically from even a decade ago, and I think our understanding of these mergers will continue to change rapidly.”

“This finding improves what we know of the many complicated events that shaped the Milky Way, helping us better understand how galaxies are formed and shaped—our home galaxy in particular,” said Timo Prusti, Project Scientist for Gaia at ESA.

The post The Milky Way’s Last Merger Event Was More Recent Than Thought appeared first on Universe Today.

To date, astronomers have confirmed the existence of 5638 extrasolar planets in 4,199 star systems. In the process, scientists have found many worlds that have defied expectations. This is certainly the case regarding “hot Neptunes,” planets that are similar to the “ice giants” of the outer Solar System but orbit much closer to their stars. But when a Johns Hopkins University-led team of astronomers discovered TIC365102760 b (aka. Pheonix), they observed something entirely unexpected: a Neptune-sized planet that retained its atmosphere by puffing up.

Sam Grunblatt, an astrophysicist with JHU’s William H. Miller III Department of Physics and Astronomy, led the research. He was joined by an international team that included NSF Graduate Research Fellow Nicholas Saunders, 51 Pegasi b Fellows Shreyas Vissapragada, Steven Giacalone, Ashley Chontos, and Joseph M. Akana Murphy, as well as researchers from many prestigious institutes and universities. The paper that describes their findings (which recently appeared in The Astrophysical Journal) is part of a series titled “TESS Giants Transiting Giants.”

Artist’s impression of JG436b, a hot Neptune located about 33 light years from Earth. Credit: STScI

Puff planets are a new class of incredibly rare exoplanets, accounting for an estimated 1% of planets in our galaxy. The team discovered Pheonix by combining data from the Transiting Exoplanet Survey Satellite (TESS) with radial velocity measurements obtained by the High Resolution Echelle Spectrometer (HIRES) at the Keck Observatory. Their data indicated that Pheonix is 0.55 times the size of Jupiter but only 0.06 times as massive, which orbits a red giant star with a period of 4.21285 days (about six times closer to its star than the distance between Mercury and the Sun).

Based on the age and temperature of its star and the planet’s remarkably low density, the team expected that Pheonix’s gaseous envelopes should have been stripped away billions of years ago. Based on its density, the team also estimates that the planet is the puffiest “puff planet” discovered to date (roughly 60 times less dense than the densest “hot Neptune”) and that it will begin spiraling into its star in about 100 million years. As Grunblatt explained in a JHU HUB press release:

“This planet isn’t evolving the way we thought it would. It appears to have a much bigger, less dense atmosphere than we expected for these systems. How it held on to that atmosphere despite being so close to such a large host star is the big question.”

“It’s the smallest planet we’ve ever found around one of these red giants, and probably the lowest mass planet orbiting a [red] giant star we’ve ever seen. That’s why it looks really weird. We don’t know why it still has an atmosphere when other ‘hot Neptunes’ that are much smaller and much denser seem to be losing their atmospheres in much less extreme environments.”

Artist’s impression of Pheonix, the “hot Neptune” orbiting a red giant star 8 billion light-years from Earth. Credit: Roberto Molar Candanosa/JHU

These findings could have implications for new insight into the late-stage evolution of planetary systems and help scientists predict what will happen to the Solar System in a few billion years. According to standard models of stellar evolution, our Sun will exit its main sequence phase, expand to become a red giant, and eventually consume the inner planets. Based on these findings, they predict that Earth’s atmosphere may not evolve the way astronomers previously expected. Instead of our Sun blasting it away, our atmosphere may expand to become incredibly “puffy.”

Pheonix is the latest puffy planet examined by the international team based on TESS data. While puff planets are known to be rare, exoplanets like Pheonix are especially elusive because of their small size and low density. In the future, Grunblatt and his colleagues plan to search for more of these smaller worlds and have already identified a dozen potential candidates by combining transit and radial velocity data.

Further Reading: John Hopkins University, The Astrophysical Journal

The post Instead of Losing its Atmosphere, an Exoplanet Puffed Up and Held Onto it appeared first on Universe Today.

The James Webb Space Telescope (JWST) has once again found evidence that the early universe was a far more complex place than we thought. This time, it has detected the signature of carbon atoms present in a galaxy that formed just 350 million years after the Big Bang – one of the earliest galaxies ever observed.

“Earlier research suggested that carbon started to form in large quantities relatively late – about one billion years after the Big Bang,” said Kavli Institute Professor Roberto Maiolino. “But we’ve found that carbon formed much earlier – it might even be the oldest metal of all.”

‘Metal’ is the name astronomers give to any element heavier than hydrogen or helium, and seeing metals like carbon so early is a surprise. Carbon is, of course, one of the building blocks of life on Earth, but it also plays a role in galaxy and solar system formation. It is one of the materials that can accumulate in the protoplanetary disks around stars, snowballing to become planets, moons, and asteroids.

But astronomers weren’t expecting to see that process happening so early.

When the first stars (called population-III stars) were born, in an era of the universe known as Cosmic Dawn, the only plentiful elements around were hydrogen and helium. All heavier elements didn’t yet exist. They were only able to form later, inside the cores of stars, therefore wouldn’t be detectable until well after the deaths of the first stars.

Dying population-III stars that explode as supernovas throw their heavier elements out into the universe, allowing future populations of stars to develop rocky planets with more interesting chemistry.

The galaxy in question, named GS-z12, is thought to contain largely second generation stars, built from the remains of those first supernovas. Astronomers didn’t expect the building blocks of the galaxy to be carbon-rich:

“We were surprised to see carbon so early in the universe, since it was thought that the earliest stars produced much more oxygen than carbon,” said Maiolino. “We had thought that carbon was enriched much later, through entirely different processes, but the fact that it appears so early tells us that the very first stars may have operated very differently.”

JWST’s Near Infrared Spectrograph allowed astronomers to break down the light coming from the distant galaxy into its constituent parts, revealing all the different wavelengths present. Every element and chemical compound has its own signature when viewed via spectroscopy, and the signal for carbon was very strong. There was also a fainter signal for neon and oxygen, though those remain tentative detections for the moment.

How carbon emerged before oxygen is an open question, but one hypothesis proposes that scientists now need to revisit their models of population-III star supernovas. If these supernovas occurred with less energy than previously thought, then they would scatter carbon from the stars’ outer shells, while most of the oxygen present would be captured within the event horizon as the stars collapsed into black holes.

Regardless of how it happened, there is now a strong case for heavy elements early in the universe – far earlier than anyone guessed. JWST is revealing unexpected details about the first galaxies that will ultimately make scientists’ predictions about the evolution of the universe far more robust. And perhaps most significantly, it also tells us about the very first step towards creating life.

“These observations tell us that carbon can be enriched quickly in the early universe,” said Francesco D’Eugenio of the Kavli Institute. “And because carbon is fundamental to life as we know it, it’s not necessarily true that life must have evolved much later in the universe. Perhaps life emerged much earlier – although if there’s life elsewhere in the universe, it might have evolved very differently than it did here on Earth.”

Learn More:

“Earliest detection of metal challenges what we know about the first galaxies.” University of Cambridge.

D’Eugenio et al. “JADES: Carbon enrichment 350 Myr after the Big Bang in a gas-rich galaxy.” ArXiv preprint (accepted to Astronomy & Astrophysics).

The post Carbon is Surprisingly Abundant in an Early Galaxy appeared first on Universe Today.

There are likely millions of “rogue” or free-floating planets (FFPs) spread through the galaxy. These planets, which aren’t big enough to become stars but also aren’t beholden to a star’s gravity, are some of the hardest objects for astronomers to spot, as they don’t give off their own light, and can only be seen when they cross in front of something that does give off its own light. Enter Euclid, a space telescope that launched last year. Its primary mission is to observe the universe’s history, but a new paper describes an exciting side project – finding FFPs in Orion.

In particular, it is finding FFPs around a system known as Sigma Orionis. Famously located on the eastern side of Orion’s Belt, this “star” is a system of at least five different stars, all gravitationally bound in one way or another, forming what is known as a “cluster.” It’s also surrounded by a “dust wave” of particles pointing at the nearby Horsehead Nebula, all of which lends itself to being a place where it would be easy to find FFPs. 

Free-floating planets of this type can also be considered “failed stars” as they did not have enough mass to start the fusion process that comes with star formation. This isn’t the first time they’ve been found in star-forming regions. Other FFPs have been found in NGC 1333, Collider 69, and even the Orion Nebula. This isn’t even the first time they’ve been found in Sigma Orionis – but it is the first time they’ve been detected with the accuracy Euclid allows. As the paper’s authors put it, they “appear to be ubiquitous and numerous.”

Fraser interviews Dr. Maggie Lieu about Euclid and its capabilities

So, what’s unique about what Euclid did? Admittedly, the paper was a sort of test run for the telescope. The observations were taken back in October, only a few months after it launched in the middle of 2023. Those observations also focused on regions well known to contain tons of FFPs already. So what did it find?

They found a bunch of much smaller FFPs than had previously been found. Astronomers use an algorithm called the Initial Mass Function (IMF) to describe the number of stars of specific sizes that would be formed. FFPs define the lower limit of that IMF – i.e., if an object isn’t big enough to become a star, it becomes an FFP. Sufficiently smaller FFPs help astronomers define the limits of the IMF in certain regions, but so far, they have escaped the notice of less sensitive detectors.

That’s where Euclid comes in. The authors point out how the lower end of the IMF is not well defined and describe how the data collected by Euclid could be used to flesh out models at the lower end of the spectrum. However, they also point out that this is still very early in Euclid’s data collection cycle, and plenty more systems could prove exciting hunting grounds for smaller FFPs than have ever been seen before.

Fraser discusses rogue planets in the Orion Nebula

For now, though, this is an excellent first test case of Euclid’s capabilities. Given the sheer number of objects that could be floating out there in the void, it will have plenty of other opportunities to find more, and it has already started looking in several other well-known places, according to the paper. It’s got more than five years left on its planned mission duration, so there will undoubtedly be more papers describing many more FFPs in the future.

Learn More:
Martín et al – Euclid: Early Release Observations – A glance at free-floating new-born planets in the ? Orionis cluster
UT – Enjoy Five New Images from the Euclid Mission
UT – Euclid Begins its 6-Year Survey of the Dark Universe
UT – Phew, De-Icing Euclid’s Instruments Worked. It’s Seeing Better Now

Lead Image:
Multi-color mosaic of the Euclid pointing studied in this work. The area covered is 0.58 square degrees
Credit – Martín et al

The post Euclid is Finding Free Floating Planets in Orion Too appeared first on Universe Today.

It should not be surprising that Venus is dry. It is famous for its hellish conditions, with dense sulphurous clouds, rains of acid, atmospheric pressures comparable to a 900 meter deep lake, and a surface temperature high enough to melt lead. But it’s lack of water is not just a lack of rain and oceans: there’s no ice or water vapour either. Like Earth, Venus is found within our Solar System’s goldilocks zone, so it would have had plenty of water when it was first formed. So where did all of Venus’s water go?

Venus is an extremely dry planet, although it wasn’t always like this. At some point in its history, a run-away greenhouse effect began, ending with its current extreme state. Most models agree that this process would have driven off most of its original water, but that there should still be some remaining. And yet, observations show us that there is practically no water at all. Planetary scientists at the University of Colorado Boulder believe that they have found an explanation: a molecule called HCO+ high in Venus’s atmosphere may be responsible. Unfortunately, they may have to wait for future missions to Venus before they can confirm it.

Until the middle of the 20th century, Venus was thought of as Earth’s twin. Both planets are approximately the same size and mass, and they’re both within the sun’s habitable zone – the region where temperatures can exist that are warm enough to melt ice, but not so hot that water boils into steam. It was long assumed that, beneath its shining white cloud cover, Venus must have a similar climate to Earth. Science fiction authors even wrote stories about visitors to Venus exploring verdant jungles and meeting exotic civilizations. But the truth is much harsher: Venus is an extreme place, with sulphuric acid rains, crushing atmospheric pressure, and a surface temperature hot enough to melt lead. But it wasn’t always like that.

The general assumption among astronomers and planetary scientists is that both Earth and Venus started life with similar amounts of water. But something happened to release enormous quantities of carbon dioxide into its atmosphere, leading to an extreme runaway greenhouse effect. The high temperatures melted off any ice, and boiled away any liquid water, filling the atmosphere with water vapour. Much of this hot vapour would eventually blow off into space, drying out the planet, but some should remain. The puzzle is that the usual models predict a great deal more remaining water vapour than what is actually there. So, what happened?

According to a study, led by Dr Eryn Cangi and Dr Mike Chafin, both of the Laboratory for Atmospheric and Space Physics (LASP), the answer may be a molecule named HCO+. In their earlier work studying the atmosphere of Mars, they discovered a process by which this molecule can remove water from planetary atmospheres. In their new paper, they suggest that the same process could be at work on Venus. The only catch is that this molecule has never been detected in the Venusian atmosphere.

Unfortunately, there is little evidence to confirm this theory. HCO+ has never been detected in the atmosphere of Venus. However, Cangi and Chafin point out that this is because nobody has ever looked for it, and none of the missions sent to Venus so far were equipped with instruments that could detect it. They are optimistic for future missions, however.

Illustration of NASA’s DAVINCI probe falling to the surface of Venus. (Credit: NASA GSFC visualization by CI Labs Michael Lentz and others)

“One of the surprising conclusions of this work is that HCO+ should actually be among the most abundant ions in the Venus atmosphere,” says Chaffin.
“There haven’t been many missions to Venus,” adds Cangi. “But newly planned missions will leverage decades of collective experience and a flourishing interest in Venus to explore the extremes of planetary atmospheres, evolution and habitability.”

The planetary science community has gotten increasingly interested in Venus, and a number of future missions are planned to study it in more detail. NASA’s planned Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission is one example. DAVINCI will drop a probe down to the surface, which will study the atmosphere at different altitudes as it falls. Unfortunately for Cangi and Chafin, it is not designed specifically to look for HCO+, but it may reveal other clues to either confirm or disprove their theory. But they remain optimistic that additional missions will be sent in future that will carry the necessary instruments that they can use to test their work.

For more information, visit CU Boulder’s announcement at https://www.colorado.edu/today/2024/05/06/venus-has-almost-no-water-new-study-may-reveal-why

The post Where Did Venus's Water Go? appeared first on Universe Today.

I’ve seen some pretty incredible things using my eyes.. First off of course, is the stunning sight of a dark star filled sky, then there is the incredible sight of the Andromeda Galaxy 2.5 million light years away. Planets too can of course be seen as they slowly move across the sky but it’s a little more unusual to see something that reminds us the Universe changes. Well, we have an opportunity  in just a few weeks time. The star T Corona Borealis (T CrB) will brighten about 1,500 times so it can be seen with the unaided eye. Miss it though and you will have to wait another 80 years!

It’s always exciting to see something new in the sky. It doesn’t happen all that often but when it does, well it’s definitely an opportunity to get out and enjoy the show. The event is a nova which translates from Latin meaning new. In astronomy, we talk of nova as a number of different phenomena which herald the appearance of something new which is visible in the sky. A supernova is a well known example marking a colossal stellar explosion.

In the case of TCrB it refers to a binary star system where a white dwarf star (the remains of a star like the Sun) is in orbit around another star. I should clarify that statement, they both orbit around a common centre of gravity. At a distance of 3,000 light years, it is one of the closest of its type and so when it goes into outburst, we will get to see it without  any telescope or binoculars, just the ‘Mark-1 eyeball.’ 

The process that leads to the sudden brightening is really quite fascinating. The white dwarf star is a much higher pull of gravity compared to its companion. As a result, it drags material from its stellar neighbour in a process known as accretion. Over time – and in the case of T CrB it takes about 80 years – hydrogen builds up on the white dwarf. The layer of hydrogen is heated up by the white dwarf causing it to heat to critically high temperatures, high enough to initiate hydrogen fusion. The layer of hydrogen detonates and gets ejected from the white dwarf in a brightly glowing, hot shell. Here on Earth, we see this as a sudden brightening of a previously rather inconspicuous star that would ordinarily need a telescope to see.

Nova are generally quite unpredictable, usually occurring once and often leading to the death of a star but in this case, it occurs every 80 years. We call this event a recurrent nova. Its outburst was first seen in 1866 by an astronomer called John Birmingham who, amusingly came from Ireland and not Birmingham. It was seen again in 1946 when there was a drop in brightness before the explosion and it is this drop in brightness that has just been observed over the last couple of months. 

This all points to the next nova event being imminent, perhaps just a month or two away so, if you like me, are keen to see this once in a lifetime event then it’s time to get your coat on and get outside. Unfortunately, because we don’t know exactly when it is going to occur the best approach is to simply become familiar with the sky in the region of the constellation Corona Borealis. 

Alphecca is the brightest star in a C-shaped pattern of stars: the constellation Corona Borealis. It’s near the bright star Arcturus on the sky’s dome. Credit: EarthSky

Thankfully, Corona Borealis is in a fairly ‘quiet’ part of the sky with not too many bright stars. To find it from where you are then use an app on a smartphone to locate Vega in Lyra and Arcturus in Bootes, Corona Borealis is approximately between the two and looks somewhat like a semicircle of stars. Get to know that part of the sky and become familiar with the stars visible to the naked eye. Keep watching over the weeks and months ahead (and of course keep an eye on Universe Today) and at some point soon, you will see a ‘new’ star appear just outside the semicircle. 

Good luck and clear skies. 

Source : Keep your eyes on the sky for a new star as “once in a lifetime” cosmic explosion looms

The post We’re Now Just Weeks Away from a Stellar Explosion You Can See With Your Own Eyes appeared first on Universe Today.

We live in a Universe studded with black holes. Countless stellar mass and supermassive ones exist in our galaxy and most others. It’s likely they existed as so-called “primordial” black holes in the earliest epochs of cosmic history. Yet, there seems to be a missing link category: intermediate-mass black holes (IMBH). Astronomers have searched for these rare beasts for years and there’s only one possible observation thanks to gravitational-wave data. So, where are they?

IMBH might be hidden away in the hearts of globular clusters. But, given the tightly packed nature of those compact collections of stars, how would we know if they contained any IMBH? Teams of researchers in Japan and China came up with a couple of ways to search them out. One is to look for fast-moving stars ejected from globular clusters. The other is to do simulations of collisions of stars in the hearts of newly forming clusters. Both methods may point the way to more IMBH discoveries.

What Are Intermediate-mass Black Holes?

These rare objects are pretty much what their name says: black holes with masses somewhere between their stellar-mass cousins and the supermassive behemoths at the hearts of galaxies. They can contain as little as a thousand times the mass of the Sun, which would be fairly “small”, up to maybe a million solar masses. Beyond that are the supermassive monsters with millions or billions of times the mass of the Sun. The IMBH don’t come from supernova explosions, since there’s no massive star big enough to collapse to produce an IMBH. The birth of an IMBH should involve multiple massive objects coalescing together. This makes them more like their big supermassive black hole siblings.

So, where would such a collisional event happen? It would help if you had a dense agglomeration of stars tightly packed together. That describes globular clusters to a T. They’re crowded with stars, and likely have a good collection of very massive ones. Those are the stars that explode as supernovae and collapse down to produce a stellar-mass black hole. If enough of them exist in the cluster, they could merge and create an IMBH. Another suggestion to create an IMBH is for massive stars to collide to create a single more-massive object.

Many globular clusters orbit the core of the Milky Way Galaxy. Some of the densest ones have millions of stars pulled together by gravity. The cluster Messier 15 (M15) is a good example. It contains more than 100,000 stars crammed into an area of space about 175 light-years across. If runaway star collisions or stellar-mass black hole mergers occurred in M15, that could be enough to create an IMBH.

Simulating Globular Clusters and Intermediate-Mass Black Hole Growth

Another idea is to explore the formation of globulars to see if it produces any clues to the origins and existence of IMBH. That’s what a team of scientists at the University of Tokyo did. They created advanced simulations of star cluster formation to see if massive-star collisions could occur and lead to the birth of IMBH. It’s not an easy task. Previous simulations suggested stellar winds would blow away the needed masses to create these missing black holes.

“Star cluster formation simulations were challenging because of the simulation cost,” said team leader Michiko Fujii. “We, for the first time, successfully performed numerical simulations of globular cluster formation, modeling individual stars. By resolving individual stars with a realistic mass for each, we could reconstruct the collisions of stars in a tightly packed environment. For these simulations, we have developed a novel simulation code, in which we could integrate millions of stars with high accuracy.”

A simulated star cluster forming in a giant molecular cloud. Could this visualization help astronomers understand the formation of intermediate-mass black holes in clusters? Courtesy: Takaaki Takeda (VASA Entertainment, Inc.)

The resulting simulation run showed that runaway collisions brought very massive stars together. These are perfect candidates to end up as IMBH candidates. “Our final goal is to simulate entire galaxies by resolving individual stars,” Fujii points to future research. “It is still difficult to simulate Milky Way-size galaxies by resolving individual stars using currently available supercomputers. However, it would be possible to simulate smaller galaxies such as dwarf galaxies. We also want to target the first clusters, star clusters formed in the early universe. First clusters are also places where IMBHs can be born.”

Runaway Stars and IMBH

Okay, so simulations show that such IMBH could be possible in the globular cluster environment, but what’s the physical proof they actually exist? No one has actually detected the collisions of stellar-mass black holes inside a cluster to create an IMBH. Nor have they seen stellar collisions that might create a monster object — although the Japanese simulations proved they can happen. The trick now is to observe both types of event. Until that happens, astronomers can figure out if IMBH exist through indirect means.

A Chinese research team, led by Yang Huang of the University of the Chinese Academy of Sciences, recently posted a paper about a high-velocity star fleeing the scene of a collision in the heart of Messier 15. The star, called J0731+3717, was ejected by an encounter with an intermediate-mass black hole embedded very close to the center of the cluster.

J0731+3717 got tossed out on its high-speed journey about 21 million years ago. The team examined its metallicity (that is, its ratios of hydrogen and heavier elements (called “metals” by astronomers)) and found that it matches the stars in M15. The rogue star moves away from the cluster at a velocity of about 550 kilometers per second and once “lived” at a distance of about 1 AU from the cluster’s core. The team analyzed those measurements and did reverse orbital calculations of that star (and others within 5 kpc of the Sun). Based on their calculations, they concluded the star had a too-close encounter with an intermediate-mass black hole containing about 100 solar masses.

The team suggests that this method be used to prove the existence of other IMBH in similar environments. They conclude their paper with a look at future observations to prove the concept. “With the increasing power of ongoing Gaia and large-scale spectroscopic surveys, we expect to discover dozens of cases within the 5kpc volume and ten times more within a 10kpc volume, which should shed light on the understanding of the evolutionary path from stellar-mass BHs to SMBHs.”

For More Information

Simulations Yield New Intermediate Mass Black Holes Recipe
Medium and Mighty: Intermediate-mass Black Holes Can Survive in Globular Clusters
A High-velocity Star Recently Ejected by an Intermediate-mass Black Hole in M15

The post Globular Clusters Should Contain More Intermediate-mass Black Holes appeared first on Universe Today.

Through the Artemis Program, NASA will send astronauts to the lunar surface for the first time since 1972. While the challenges remain the same, the equipment has evolved, including the rocket, spacecraft, human landing system (HLS), and space suits. In preparation for Artemis III (planned for September 2026), NASA recently conducted a test where astronauts donned the new space suits developed by Axiom Space and practiced interacting with the hardware that will take them to the Moon.

These new suits, the Axiom Extravehicular Mobility Unit (AxEMU), were developed specifically for the Artemis III mission. The day-long test took place on April 30th at SpaceX headquarters in Hawthorne, California, where astronaut Doug “Wheels” Wheelock and Axiom Space astronaut Peggy Whitson interacted with a full-scale model of the SpaceX Starship Human Landing System (HLS). This was the first time astronauts trained in pressurized spacesuits and conducted mock operations with the HLS hardware.

The Artemis III spacesuit prototype, the AxEMU. Though this prototype uses a dark gray cover material, the final version will likely be all-white when worn by NASA astronauts on the Moon’s surface. Credit: Axiom Space

The test provided valuable feedback on the Starship HLS and the AxEMU spacesuits for NASA and its commercial partners. It also gave astronauts a chance to gauge the suits’ range of motion and to get a feel for the interior of the Starship HLS and its mechanical systems. Said Logan Kennedy, lead for surface activities in NASA’s HLS Program, in a NASA press statement:

“Overall, I was pleased with the astronauts’ operation of the control panel and with their ability to perform the difficult tasks they will have to do before stepping onto the Moon. The test also confirmed that the amount of space available in the airlock, on the deck, and in the elevator, are sufficient for the work our astronauts plan to do.”

The test consisted of Wheelock and Whitson practicing putting on and taking off the spacesuits – which included the suit’s Portable Life Support System (PLSS) – in the Starship HLS‘ full-scale airlock. Since the Artemis III astronauts will need to put the suits on with minimal assistance, this test allowed NASA to test how easily the suits are to get in and out of. The suits were then pressurized and powered up, and Wheelock and Whitson began interacting with the mobility aids (handrails and straps) and control panel in the airlock.

They then walked from the airlock deck to the HLS elevator, which will take the Artemis III astronauts and their equipment to the lunar surface to conduct extravehicular activity (EVA). Though the tasks were routine, they validated the spacesuit design and brought NASA one step closer to achieving its goals through the Artemis Program. As Amit Kshatriya (NASA’s Moon to Mars program manager) expressed:

“With Artemis, NASA is going to the Moon in a whole new way, with international partners and industry partners like Axiom Space and SpaceX. These partners are contributing their expertise and providing integral parts of the deep space architecture that they develop with NASA’s insight and oversight. Integrated tests like this one, with key programs and partners working together, are crucial to ensure systems operate smoothly and are safe and effective for astronauts before they take the next steps on the Moon.”

Wheelock and Whitson tested the agility of the spacesuits by conducting movements and tasks similar to those necessary during lunar surface exploration on Artemis missions. Credit: SpaceX

Putting the spacesuits through rigorous testing is necessary since the Artemis III mission will include EVAs in space and on the lunar surface. The four-person crew will launch aboard an Orion spacecraft atop NASA’s Space Launch System (SLS) while the Starship HLS launches separately and refuels in orbit. The Orion spacecraft will rendezvous and dock with the HLS in lunar orbit; two astronauts will transfer aboard and then take the HLS to and from the lunar surface. The AxEMU suits are designed to provide greater flexibility and accommodate a wider range of astronauts.

This is in keeping with NASA’s commitment to diversity, equity, and inclusion in its astronaut corps. Despite delays, things are undeniably coming together for Artemis III!

Further Reading: NASA

The post Astronauts are Practicing Lunar Operations in New Space Suits appeared first on Universe Today.

Red dwarf stars, also known as M-dwarfs, dominate the Milky Way’s stellar population. They can last for 100 billion years or longer. Since these long-lived stars make up the bulk of the stars in our galaxy, it stands to reason that they host the most planets.

Astronomers examined one red dwarf star named SPECULOOS-3, a Jupiter-sized star about 55 light-years away, and found an Earth-sized exoplanet orbiting it. It’s an excellent candidate for further study with the James Webb Space Telescope.

SPECULOOS stands for the Search for habitable Planets EClipsing ULtra-cOOl Stars. It’s a European Southern Observatory effort that searches for terrestrial planets orbiting cool stars like red dwarfs. (Its odd name is an homage to a Belgian sweet biscuit.) Its goal is to find planets that are good targets for spectroscopy with the JWST and the ELT.

The new planet is named SPECULOOS-3b, and its discovery was presented in a recent paper in Nature Astronomy. The paper is titled “Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3.” The lead author is Michaël Gillon from the Astrobiology Research Unit, Université de Liège, Belgium.

SPECULOOS is an automated search using four telescopes around the world: one at the Paranal Observatory in Chile, one at the Teide Observatory in Tenerife, one at the La Silla Observatory in Chile, and one at the Oukaïmden Observatory in Morocco. The project is searching 1,000 ultra-cool stars and brown dwarfs for terrestrial planets.

One of the problems in detecting planets around these stars is their low luminosity. Since they’re so dim, transiting exoplanets are difficult to detect, making their planetary populations difficult to characterize and study. So far, astronomers have found only one planetary system around one of these stars, and it’s rather well-known: the TRAPPIST-1 system. When it began, the SPECULOOS program expected to find at least one dozen systems similar to TRAPPIST-1.

“We designed SPECULOOS specifically to explore nearby ultra-cool dwarf stars in search of rocky planets,” lead author Gillon said. “With the SPECULOOS prototype and the crucial help of the NASA Spitzer Space Telescope, we discovered the famous TRAPPIST-1 system. That was an excellent start!”

The dimness of these stars can’t be understated. “Though this particular red dwarf is more than a thousand times dimmer than the Sun, its planet orbits much, much closer than the Earth, heating up the planetary surface,” said co-author Catherine Clark, a postdoctoral researcher at NASA’s JPL in Southern California.

The new planet is an Earth-sized world that orbits its star in only 17 hours. The star has a spectral type M6.5, and it delivers 16.5 more solar irradiation to its planet than the Sun does to Earth. That may sound surprising since the star is much cooler than the Sun. The Sun’s surface temperature is 5,772 K (5,500 C), while SPECULOOS-3’s temperature is only 2,900 K (2,627 C.) But SPECULOOS 3 bombards the planet with radiation due to the small distance separating them.

Since the irradiation is largely infrared and the star is only Jupiter-sized, it makes the planet an exceptional candidate for follow up observations, which is exactly what the SPECULOOS program is all about. The SPECULOOS Program 1 has found about 365 temperate, Earth-sized targets for further study with the JWST.

This chart shows the classifications by spectral type for main sequence stars according to the Harvard classification. Image Credit: By Pablo Carlos Budassi – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=92588077

The SPECULOOS-3 system is about 6.6 billion years old. Its luminosity, mass and radius are 0.084%, 10.1% and 12.3% of those of the Sun. “Just slightly larger than TRAPPIST-1, SPECULOOS-3 is the second-smallest main sequence star found to host a transiting planet,” the authors explain in their paper.

Two different telescopes observed the planetary transits around the star in 2021 and 2022 over eight nights. “Visual inspection of the 2021 and 2022 light curves showed some transit-like structures that motivated future intensive monitoring of the star,” the authors explain. The star was re-observed in 2023.

This figure from the study shows the transit of SPECULOOS-3b around its dim, cool star. Image Credit: Gillon et al. 2024.

The researchers determined that SPECULOOS-3b is about the same size as Earth, about 96% of our planet’s radius. But the planet’s density and mass are so far unconstrained. “Nevertheless,” the authors write in their paper, “several factors strongly suggest a rocky composition.”

There are two empirical reasons why the planet is likely rocky, though. The first is that its radius is on the rocky side of the radius gap. The second is that “all of the known Earth-sized planets in the NASA exoplanet archive have masses that imply rocky compositions,” Gillon and his co-authors explain.

This figure from the research compares SPECULOOS-3b to other transiting terrestrial exoplanets with less than 1.6 Earth radii. All of these planets are also cool enough to have rocky daysides rather than molten daysides. The shaded green area highlights planetary radii most similar to Earth’s (0.9–1.1R). Image Credit: Gillon et al. 2024.

But the big question concerns the planet’s potential atmosphere.

“From a theoretical point of view, the intense extreme ultraviolet emission of low-mass stars during their early lives makes it unlikely that such a small planet on such a short orbit could have maintained a substantial envelope of hydrogen.” the authors explain.

Red dwarfs are known to emit extreme radiation that strips away planetary atmospheres. However, there is some evidence that some planets can hold on to their atmospheres despite intense radiation, as with the recently discovered TIC365102760 b. Only time and more observations can tell us if the planet has an atmosphere and what type it has.

The researchers watched closely to see if there was a second planet around the star but didn’t find one. They also examined the planet spectroscopically with ground-based facilities. But we’ll have to wait for the JWST to examine the planet before we can really understand its atmosphere. The two most likely types of atmospheres for hot rocky planets are CO2-dominated and H2O-dominated.

The JWST will be able to examine SPECULOOS-3b with emission spectroscopy. This means it can examine the light the planet is emitting rather than just the light from the star as it passes through the atmosphere, which is called transmission spectroscopy. Emission spectroscopy is unaffected by irregular stellar behaviour, which red dwarfs are known to exhibit. JWST emission spectroscopy can also help determine the surface mineralogy if there’s no atmosphere. There’s a potential wealth of information waiting to be uncovered.

“We’re making great strides in our study of planets orbiting other stars,” said Steve B. Howell, one of the planet’s discoverers at NASA Ames Research Center. “We have now reached the stage where we can detect and study Earth-sized exoplanets in detail. The next step will be to determine whether any of them are habitable or even inhabited.”

The post An Earth-sized Exoplanet Found Orbiting a Jupiter-Sized Star appeared first on Universe Today.

Despite being extraordinarily difficult to detect for the first time, gravitational waves can be found using plenty of different techniques. The now-famous first detection at LIGO in 2015 was just one of the various ways scientists had been looking. A new paper from researchers from Europe and the US proposes how scientists might be able to detect some more by tracking the exact position of the upcoming Uranus Orbiter and Probe (UOP).

Initially suggested by NASA’s Planetary Science and Astrobiology Decadal Survey, UOP will be the first mission to Uranus since Voyager visited the system in 1986. When it finally arrives in 2044, after a 2031 launch date, it will be almost 60 years since humanity last had an up-close look at the Uranian system.

But 13 years in transit sure is a long time. Part of that time will be spent getting a gravitational boost from Jupiter, but most will be spent coasting between planetary bodies. And that much time spent in between planets is what the paper’s authors want to utilize to do non-Uranian science.

Fraser has long been a proponent of returning to Uranus, as he explains here.

Gravitational waves can disrupt the fabric of space-time, causing discernible distortions, especially over long distances. If the instruments in question are sensitive enough, the massive distance between UOP and the Earth would be a viable way to detect them.

This isn’t the first time using the distance between a spacecraft and Earth has been considered for detecting gravitational waves. Pioneer 11, Cassini, and a triangulation of Galileo, Ulysses, and Mars Orbiter all had entertained suggestions of being utilized for gravitational wave detection while on their journey to their final destinations. However, the equipment they were designed with was not sensitive enough to pick up the minute fluctuations required for an actual detection.

UOP will have the added advantages of decades of improved equipment, especially communications and timing electronics, which are critical to any gravitational wave detection. It also benefits that we’ve already officially detected a gravitational wave, so we know at least what to look for.

Long distance communication is hard, as Fraser explains in this video, but it’s also key to capturing data on gravitational waves.

The underlying mechanism is simple enough – consistently track the exact established position of UOP during its 13-year cruise to Uranus and cross-reference any anomalies in its position against what could be expected from known causes. These include the gravitational pull of some of the planets, or even asteroids, and solar radiation pressure on the spacecraft itself. As the authors note, some or even all of these could impact the spacecraft’s exact position; for the calculations to work effectively to find gravitational waves, better accounting for what, if any, impact they have must be completed.

But there is another potentially scientifically interesting cause of slight positional drift for the UOP: ultra-light dark matter. In theory, UOP could be used to test or even directly detect a form of dark matter known as ultra-light dark matter if it happens to exist in the solar system. Theorists have numerous models showing how it would work if it did exist. UOP could also use the same sort of exact positional calculation to contribute to that scientific research.

Best of all, UOP can do all this with literally no change to its primary functional mission – exploring the Uranian system. All that would have to be changed about the mission would be to update Earth with consistent positional data about once every 10 seconds for the duration of the 13-year trip to UOP’s final destination. Suppose there’s a chance that those more frequent check-ins with home could help detect gravitational waves or potentially dark matter. In that case, it seems well worth the consideration of the UOP mission planners – but it remains to be seen whether it will be included or not. The paper’s authors have made a persuasive argument about why it should be.

Learn More:
Zwick et al. – Bridging the micro-Hz gravitational wave gap via Doppler tracking with the Uranus Orbiter and Probe Mission: Massive black hole binaries, early universe signals and ultra-light dark matter
UT – It’s Time to Go Back to Uranus. What Questions do Scientists Have About the Ice Giants?
UT – We Could SCATTER CubeSats Around Uranus To Track How It Changes
UT – What Mission Could Detect Oceans at Uranus’ Moons?

Lead Image:
Proposed Uranus orbiter mission.
Credit – NASA Decadal Survey

The post A Mission to Uranus Could Also be a Gravitational Wave Detector appeared first on Universe Today.

SpaceX’s Starship earned high marks today in its fourth uncrewed flight test, making significant progress in the development of a launch system that’s tasked with putting NASA astronauts on the moon by as early as 2026.

The Super Heavy booster blasted off from SpaceX’s Starbase complex in South Texas at 7:50 a.m. CT (12:50 p.m. UTC), rising into the sky with 32 of its 33 methane-fueled Raptor engines blazing. Super Heavy is considered the world’s most powerful launch vehicle, with 16.7 million pounds of thrust at liftoff.

Minutes after launch, the rocket’s upper stage — known as the Ship — separated from the first stage, firing up its own set of six Raptor engines. Meanwhile, Super Heavy flew itself to a controlled splashdown in the Gulf of Mexico.

The soft splashdown marked a new achievement for Starship. During the third flight test, which took place in March, only a few of Super Heavy’s engines were able to light up again for a crucial landing burn. As a result, the booster hit the water with an uncontrolled splat.

Eventually, SpaceX plans to have the Super Heavy booster fly itself back to its base after doing its job.

The upper stage reached orbital-scale altitudes in excess of 200 kilometers (125 miles), but completing a full orbit wasn’t part of today’s plan. Instead, SpaceX aimed to have Ship make its own soft splashdown in the Indian Ocean.

Streaming video, relayed via SpaceX’s Starlink satellite network, showed the rocket’s protective skin glowing with the heat of atmospheric re-entry. Burning debris broke off from one of Ship’s control fins, damaging the camera’s lens — but the fuzzy view nevertheless confirmed that the spacecraft successfully hit the mark. That represented another advance over the third test, when the Ship broke up during its descent to the ocean.

“Despite loss of many tiles and a damaged flap, Starship made it all the way to a soft landing in the ocean!” SpaceX founder Elon Musk exulted in a posting to his X social-media platform.

NASA Administrator Bill Nelson added his congratulations on X, and noted that the successful test was a plus for the space agency’s Artemis moon program. “We are another step closer to returning humanity to the moon through Artemis — then looking onward to Mars,” he wrote.

A customized version of Ship is slated to serve as the lunar lander for Artemis 3, which would mark the first crewed mission to the moon’s surface since Apollo 17 in 1972. That mission is currently scheduled for 2026, but the timing depends in part on when the Starship system will be ready.

SpaceX’s uncrewed flight tests are following a step-by-step path to get Starship in shape for a wide variety of missions — including the deployment of hundreds of Starlink satellites, point-to-point travel between spaceports on Earth, and crewed odysseys to the moon, Mars and beyond.

Starship rockets aren’t carrying payloads for these early tests. “We said it before, we’re going to say it 9,000 times: The data is the payload,” SpaceX commentator Dan Huot said during today’s flight test.

But as the development program proceeds, the envelope for the flight tests will be widened to include multi-orbit operations, payload deployments and precision touchdowns on landing pads. Before today’s test, SpaceX and the Federal Aviation Administration worked out an arrangement that’s expected to streamline the regulatory process for future flights.

The post Success! SpaceX’s Starship Makes a Splash in Fourth Flight Test appeared first on Universe Today.

Thirty-four years is a long time for a telescope. Yet, that is how long the veteran workhorse of NASA’s space telescope fleet has been operating. Admittedly, Hubble was served by several repair missions during the space shuttle era. Still, the system has been floating in the void and taking some of humanity’s most breathtaking pictures ever captured since April 24th, 1990. But now, time seems to be finally catching up with it, as NASA plans to limit some of its operations to ensure its continued life, starting with gyroscopes. 

Hubble has six gyroscopes, which are intended to help it orient in the right direction and ensure it stays oriented in that direction while it takes the extremely long-exposure, detailed images it is famous for. The six gyroscopes currently installed replaced six older ones during the final shuttle servicing mission in 2009. As one of the few moving components on Hubble, lasting 15 years without maintenance is pretty impressive.

That being said, not all of them lasted that long – only three are operational at this point, with the other three having failed at some point over the last 15 years. And on May 24th, the telescope was sent into safe mode by another failed gyro. This isn’t the first time that particular problem has happened either. Previous errors caused by the same gyro have caused Hubble to go into safe mode multiple times over the past few months. While engineers can reset it, the same problem repeatedly happening means it will probably continue.

Scott Manley explains how the gyros work on Hubble, and how the engineers plan to keep them working.
Credit – Scott Manley YouTube Channel

The problem is that the gyro is “saturating,” meaning that the sensor that shows its speed is maxing out even when the gyro itself isn’t moving near that speed. Since the spacecraft slewing at maximum speed could cause potential issues, the safe thing to do when reading a maximum speed on a gyro is to go into “safe mode” and ensure the spacecraft doesn’t wildly swing in one direction.

Operating in that mode makes sense, especially if the sensor readings are correct, but they make it almost impossible to move accurately if sensor readings aren’t correct. Given the previous efforts by Hubble’s engineering team to fix the problem, it appears at least one of the three remaining gyros is effectively inoperable from now on. So, the team now has a choice.

They could continue to operate with two gyros, or they could only use one and alternate which one they are using to not cause undue wear and tear on whichever one is selected for service first. According to a press release from the agency, operating with two gyros is effectively the same as operating with one, whereas operating with three had significant advantages in terms of speed and accuracy. So, the engineering team has decided that Hubble will operate in one gyro mode from now on.

Fraser discusses some of Hubble’s most iconic images – it’s set of Deep Fields.

This isn’t the first time it’s done so—Hubble effectively operated in one-gryo mode for a short time back in 2008 when the previous set of gyros was failing. It also operated in two-gyro mode from 2005 to 2009, when all the original gyros were replaced. So it is certainly possible, but what impact will it have?

It will take longer to lock on to targets, which is hardly surprising given the telescope’s age, but detrimental if it was hoping to catch transient events such as a supernova. It also won’t be able to track any moving objects that are closer than Mars, such as the occasional comet or asteroid. Typically, those types of objects weren’t the focal point of Hubble’s observations anyway. While Hubble will indeed have to slow down, its support team believes it can continue operations through at least the rest of this decade in this new mode.

Luckily, it is no longer alone in its role as the workhorse space telescope. The James Webb Space Telescope has far surpassed its observational capabilities; the Nancy Grace Roman Telescope, due to launch in 2027, will contribute additional functionality to make up for Hubble’s slowing pace. Hubble itself will always have a place in astronomy nerds’ hearts. Its Deep Field image is my favorite picture and sparked my love for astronomy as a kid. And I’m not alone – NASA recently rejected billionaire Jared Isaacman’s plan to service the aging telescope as part of a series of Dragon capsule missions. But even without additional help from the ground, Hubble hopefully still has a long, fruitful life ahead of it when it continues its science operations in mid-June.

Learn More:
NASA – NASA to Change How It Points Hubble Space Telescope
UT – Hubble Pauses its Science Again
UT – The Venerable Hubble Space Telescope Keeps Delivering
UT – Hubble Sees a Brand New Triple Star System

Lead Image:
This image of NASA’s Hubble Space Telescope was taken on May 19, 2009, after deployment during Servicing Mission 4.
Credit – NASA

The post It’s Time for Hardworking Hubble to Slow Down a Little appeared first on Universe Today.

A pair of Chinese taikonauts have completed an eight-hour spacewalk repairing damage to the Tiangong Chinese Space Station’s solar panels. It’s believed the damage was caused by tiny pieces of space debris, which impacted the solar wings and degraded their function. They performed a first repair spacewalk in December 2023 and completed the repairs with their second trip outside in March 2024. The Shenzhou 17 crew were the sixth group living in Tiangong and were relieved by the Shenzhou-18 team in late April.

The Shenzhou-18 mission, launched prior to the conclusion of Shenzhou-17, will last approximately six months. The crew, consisting of Ye Guangfu, Li Cong, and Li Guangsu, launched from the Jiuquan Satellite Launch Center aboard a Long March 2F rocket at 20h59 Beijing Time. Their spacecraft docked with the station’s Tianhe core module approximately six and a half hours after liftoff. On May 28, 2024, Ye Guangfu and Li Guangsu executed China’s longest spacewalk to date, lasting eight and a half hours, installing a space debris protection device on the station.

Senior Colonel Tang Hongbo and Lieutenant Colonel Jiang Xinlin completed nearly eight hours of extravehicular activity to repair damage to the Tianhe core module’s solar wings caused by impacts from tiny space debris. Lieutenant Colonel Tang Shengjie provided internal support throughout the operation, which marked the first instance of such a repair by Chinese taikonauts. This event, the 15th spacewalk conducted by Chinese astronauts, underscores the critical nature of maintaining the station’s integrity and safety. These operations are complex, but vital and require precise coordination and planning between the astronauts and ground control.

Although the term “spacewalk” is commonly used, the official term for when an astronaut ventures outside a spacecraft is Extravehicular Activity (EVA). The definition of an EVA can vary depending on the country conducting the operation. For instance, Russian and Soviet spacecraft designates an EVA as any instance where a cosmonaut spends time in a vacuum while in a space suit, using specialized airlocks for this purpose. In contrast, the American definition requires at least the astronaut’s head to be outside the spacecraft. Regardless of the definition, an EVA involves leaving the protective environment of the spacecraft and entering outer space, the area outside of Earth’s atmosphere. China made history as the third country to independently perform an Extravehicular Activity (EVA) on September 27, 2008, during the Shenzhou-7 mission. During this mission, Chinese taikonaut Zhai Zhigang completed a 22-minute spacewalk, fully exiting the spacecraft while wearing the Chinese-developed Feitian space suit. Taikonaut Liu Boming, dressed in the Russian-derived Orlan space suit, assisted Zhai by standing by at the airlock and straddling the portal.

The vacuum of space presents significant dangers due to its near complete lack of gas pressure. On Earth, our atmosphere, a mix of nitrogen, oxygen, and hydrogen gases, exerts a pressure of about 101 kilopascals at sea level, which our bodies are accustomed to. In space, however, the absence of pressure means that without a proper space suit, the air in an astronaut’s lungs would rapidly escape, and gases in body fluids would expand, causing severe internal damage. Additionally, astronauts face extreme temperatures, with sunlit objects reaching over 248 degrees Fahrenheit (120 degrees Celsius) and shaded areas dropping below negative 212 degrees Fahrenheit (negative 100 degrees Celsius). Furthermore, radiation from the sun, ultraviolet rays, and tiny meteoroids pose additional hazards.

To mitigate these risks, space suits are designed to maintain life support in the vacuum of space while allowing for sufficient mobility to perform tasks. These suits are essential for EVAs, providing the necessary protection against the harsh conditions of outer space. This advanced technology enables astronauts like those from the Shenzhou-17 crew to conduct critical repair operations and scientific experiments, ensuring the continued functionality and safety of missions aboard the Tiangong space station.

Since 2021, China has significantly advanced its space capabilities by conducting numerous extravehicular activities, each lasting several hours. These EVAs have been crucial for the construction and maintenance of the Tiangong space station.

During their time on the station, the Shenzhou-17 crew continued with planned space science experiments, technical tests, planned maintenance, and the installation of extravehicular payloads. Their tenure concluded with a handover to the incoming Shenzhou- 18 crew, ensuring the continuous operation of the Tiangong space station.

The recent repair and continued maintenance operations by both crews not only demonstrate China’s growing expertise in manned spaceflight but also highlight the collaborative and technical challenges of sustaining life and functionality in the harsh environment of space. The Tiangong space station is an important platform for research and technological advancement. The dedication of the Shenzhou crews, and the ongoing operational improvements in orbit pave the way for long term and sustained human activities far beyond our atmosphere.

The post Chinese Astronauts Just Repaired Space Debris Damage Outside the Station appeared first on Universe Today.

After many delays and two scrubbed launch attempts, Boeing’s CST-100 Starliner successfully launched earlier today! The Crewed Flight Test (CFT) took off from Space Launch Complex-41 at Cape Canaveral Space Force Station, Florida, at 10:52 a.m. EDT (07:52 PDT) atop a ULA Atlas V rocket. For this mission, the capsule is carrying two NASA astronauts: Barry “Butch” Wilmore (commander) and Sunita “Suni” Williams (pilot). They are expected to reach the International Space Station (ISS) at 12:15 p.m. EDT (09:15 a.m. PDT) on Thursday, June 6th.

Assuming all goes to plan, this mission will effectively validate the Starliner as part of NASA’s Commercial Crew Program (CCP). Then, we can expect it to make regular deliveries of cargo and crew to the ISS alongside SpaceX’s Crew Dragon spacecraft. This mission is the second time the Starliner has flown to the ISS and the third flight test overall. During the first test flight (OFT-1), which took place back in December 2019, the Starliner launched successfully but failed to make it to the ISS. After making 61 corrective actions recommended by NASA, another attempt was made (OFT-2) on May 22nd, 2022.

#Starliner ascends to the heavens!

Congratulations to @NASA, @BoeingSpace, and @ulalaunch. Today's launch is a milestone achievement for the future of spaceflight.

Butch and Suni—safe travels through the stars. See you back home.
pic.twitter.com/FYRzx7q4tN

— Bill Nelson (@SenBillNelson) June 5, 2024

Though two of the spacecraft’s thrusters failed during the flight, the spacecraft managed to reach the ISS and delivered 227 kg (500 lbs) of cargo. After nearly two years of delays, another attempt was made on June 1st, but the launch was scrubbed 3 minutes and 50 seconds before liftoff due to a faulty power supply. But, as they say, the third time is the charm! The launch was followed by a NASA news conference at the Kennedy Space Center in Florida, beginning at 12:30 a.m. EDT (09:30 a.m. PDT), which NASA live-streamed via NASA+, the NASA app, YouTube, and the agency’s website.

The conference was chaired by NASA Administrator Bill Nelson, Associate Administrator Ken Bowersox and Deputy Associate Administrator Joel Montalbano (NASA’s Space Operations Mission Directorate), Manager Steve Stitch and Mark Nappi (the manager and VP and program manager of CCP), and ULA president and CEO Tory Bruno. You can check out the recap here:

NASA+ will also cover the Starliner‘s approach to the ISS, starting at 09:15 a.m. EDT (06:15 PDT) on June 6th.

Further Reading: NASA

The post Starliner Finally Launches, Carrying Two Astronauts Into Orbit appeared first on Universe Today.