Space News & Blog Articles

It’s a classic statement shared at many public outreach events…’we are made of stardust’. It is true enough that the human body is mostly water with some other elelments like carbon which are formed inside stars just like the Sun. It’s not just common elements like carbon though for we also have slighly more rare elements like iodine and bromine. They don’t form in normal stars but instead are generated in collisions between neutron stars!  It poses an interesting question, without the neutron star merger event; ‘would we exist?’

Among the plethora of elements in the human body, Iodine – which is part of the thyroid hormone system and various physiological functions such as grown, development, body temperature regulation and heart rate and bromine which is responsible for tissue development and structural integrity. These elements are formed in systems where two neutron stars are orbiting each other but lose energy through the emission of gravity waves. As the system loses energy, the neutron stars spiral closer and closer to each other culminating in a collision and the creation of iodine and bromine. 

Neutron stars are formed when a massive star runs out of its fuel and undergoes collapse. As the core of the star collapses, the pressure and temperatures increase compressing all the protons and electrons into a neutron. If the mass falls within about 1 to 2 times the mass of the Sun then the collapse halts and a neutron star is formed. These objects can result in a stellar corpse the size of a city- approximately 20 km across. A sugar cube sized piece of neutron star material would weight in at 1 trillion kilograms here on Earth. that’s equivalent to the mass of a mountain! For those stars with more mass then the collapse continues to become a stellar mass blackhole. 

When neutron stars collide as described earlier in this article, the event is known as a kilonovae. Certainly if Earth happened to live in the blast zone then it would most definitely not be conduscive to live but, the elements synthesized are key elements supporting our very existience. The process is known as the rapid neutron-capture, or the r-process for short. Seed nuclei capture a series of neutrons just in time to avoid radioactive decay before another neutron is captured. 

The paper that was written by John Ellisa, Brian D. Fields and Rebecca Surman was published recently and it articulates the importants of the elemtns to human physiology. It also explores the possibility of searching for samples in the lunar surface that may have been depsotied by a recent kilonova explosion. 

When the interstellar object (ISO) Oumuamua appeared in our Solar System in 2017, it generated a ton of interest. The urge to learn more about it was fierce, but unfortunately, there was no way to really do so. It came and went, and we were left to ponder what it was made of and where it came from. Then, in 2019, the ISO comet Borisov came for a brief visit, and again, we were left to wonder about it.

There’s bound to be more of these ISOs traversing our Solar System. There’s been talk of having missions ready to go to visit one of these interstellar visitors in the future, but for that to happen, we need advance notice of its arrival. Could the Vera Rubin Observatory tell us far enough in advance?

No mission leaves the launch pad without detailed planning, and detailed planning depends on observations. Ground-based observations laid the foundation for our forays into the Solar System. NASA missions like OSIRIS-REx, Lucy, and Psyche are simply impossible without detailed ground observations preparing the way.

Soon, one of our most powerful and unique observatories will begin operations, the Vera Rubin Observatory. Its main activity will be the Legacy Survey of Space and Time (LSST.) The LSST will image our Solar System in far more detail than ever before, and it’ll do it continuously for a decade. The wealth of data that flows from those observations will be a massive benefit to mission planning and will probably inspire missions that we haven’t dreamed of yet.

The VRO’s Legacy Survey of Space and Time is based on the observatory’s 8.4 meter, wide-angle primary mirror and its ability to change targets in only five seconds. Attached to it is the world’s largest digital camera, a 3.2 gigapixel behemoth. The VRO will image the entire available night-time sky every few nights.

It was a $325 million dollar project that was intentionally smashed to smithereens in the interest of one day, saving humanity. The DART mission (Double Asteroid Redirection Test) launched in November 2021 on route to asteroid Dimorphos. Its mission was simple, to smash into Dimorphos to see if it may be possible to redirect it from its path. On impact, it created a trail of debris from micron to meter sized objects. A new paper analyses the debris field to predict where they might end up. 

Asteroid Dimorphos orbits around its host asteroid, Didymos and together they form a binary asteroid system. Neither asteroid poses a threat to Earth but their gave a fabulous opportunity to test technology for defending Earth from potential impactors. On 11 October NASA announced that DART successfully altered the orbit of Dimorphos showing that the kinetic energy of a spacecraft could indeed alter the trajectory of a potential threat. 

DART hit Dimorphos in an almost head on collision and the resulting ejecta plume travelled at approximately 2km/s. The plume had been observed by the Les Makes Observatory and with the Hubble Space Telescope. The debris contained material from dust sized particles to meteor and even boulder sized objects. Just before the impact, the CubeSat LICIACube was released from DART so that it could offer some long term monitoring of the debris field. 

Observations that followed showed delicate structures within the ejecta with a diffuse cloud that quickly transformed into a cone shaped formation with a tail. That tail, just like the tail of a comet was then pushed away from the asteroid system by the solar radiation pressure. Using ground based imagery, the mass and velocity of the ejected particles was established. 

The analysis of ejecta enabled modelling to be undertaken to estimate that approximately 3% of all ejected boulders would remain in orbit after 83 days (within the scope of the captured data). This estimation was in line with the pre-impact simulations over a 60 day period. By varying the parameters of the simulation they also revealed that 5% of 10cm sized particles escaping with a velocity of 0.12 and 0.18m/s would remain in orbit around the system after a 60 day period of time, similar again to the observations. 

Now and then there is a bright radio flash somewhere in the sky. It can last anywhere from a few milliseconds to a few seconds. They appear somewhat at random, and we still aren’t sure what they are. We call them fast radio bursts (FRBs). Right now the leading theory is that they are caused by highly magnetic neutron stars known as magnetars. With observatories such as CHIME we are now able to see lots of them, which could give astronomers a new way to measure the rate of cosmic expansion.

The rate of cosmic expansion is described by the Hubble parameter, which we can measure to within a few percent. Unfortunately, our various methods of measure are now so precise their uncertainties don’t overlap. This contradiction in values is known as the Hubble tension. Several re-evaluations of our methods have ruled out systematic error, so astronomers look to new independent ways to measure the Hubble parameter, which is where a new study comes in.

The paper looks at using FRBs as a Hubble measure. For light from an FRB to reach us, it needs to travel millions of light-years through the diffuse intergalactic and interstellar medium. This causes the frequency of the light to spread out. The amount of spectral spreading is known as the Dispersion Measure (DM), and the greater the DM the greater the distance. So we know the distance to FRBs. But to measure cosmic expansion, we also need a second distance measure, and here the paper proposes using gravitational lensing.

If the FRB light path passes relatively close to a massive object such as a star, the light can be gravitationally lensed around the object. From the width of the lensing, we have an idea of its relative distance to the FRB source. When the FRB light passes from the intergalactic medium to the more dense interstellar medium of our galaxy, there is a brightening effect known as scintillation, which gives us another distance measure A bit of geometry then allows us to calculate the Hubble parameter.

Based on their calculations, the authors estimate that a single lensed FRB observation would allow them to pin down the Hubble parameter to within 6% accuracy. With 30 or more events, they should be able to increase their precision to a fraction of a percent uncertainty. This would put it on par with other methods. This should be achievable given current and planned FRB telescopes.

One of my favourite science and engineering facts is that an underground river was frozen to enable the Large Hadron Collider (LHC) to be built! On its completion, it helped to complete the proverbial jigsaw of the Standard Model with is last piece, the Higgs Boson. But that’s about as far as it has got with no other exciting leaps forward in uniting gravity and quantum physics. Plans are now afoot to build a new collider that will be three times longer than the LHC and it will be capable of smashing particles together with significantly more energy. 

In the past few decades, particle colliders have become a key tool for unraveling the mysteries of the universe at the fundamental level. The Large Hadron Collider (LHC), was a game changer and, with an amazing 27km circumference became the world’s most powerful collider. There are now plans to increase the number of collisions to try and improve its input to understanding the Universe but even with this ‘High Luminosity’ phase, CERN (European Council for Nuclear Research) wants to go even further and build a new collider!

If colliders like LHC are to play a part in high energy physics over the coming years then energy thresholds need to pushed beyond current capabilities. The Future Circular Collider (FCC) study has looked into various collider designs, envisaging a research infrastructure housed within a 100km underground tunnel. This ambitious project is promising a physics program that will take high energy research into the next century. 

There are a number of challenges that face the design and engineering of the new tunnel however; it must steer clear of geologically interesting areas, optimise future collider efficiency, allow for connectivity with the LHC, and adhere to social and environmental impacts of the surface buildings and infrastructure. Choosing ‘where to put it’ seems to be quite the challenge so a range of layout options are being considered, guided by CERN’s intent to avoid the impact on the area.

Within the FCC tunnel (which looks like it will be placed beneath ring-shaped underground tunnel located beneath Haute-Savoie and Ain in France and Geneva in Switzerland) will be two colliders that will work together sequentially. The first phase is scheduled for inauguration around mid-2040s and comprises an electron-positron collider (FCC-ee). The hope is that it will give unparalleled precision measurements and unveil physics beyond the standard model. Following hot on its heels will be the proton-proton collider (FCC-hh) which will surpass the energy capability of LHC eightfold!

What is it about galaxies and dark matter? Most, if not all galaxies are surrounded by halos of this mysterious, unknown, but ubiquitous material. And, it also played a role in galaxy formation. The nature of that role is something astronomers are still figuring out. Today, they’re searching the infant Universe, looking for the tiniest, brightest galaxies. That’s because they could help tell the tale of dark matter’s role in galactic creation.

An international team of astronomers led by UCLA’s Smadar Naoz is doing simulations of early galaxy formation. Their computer programs track the circumstances of galactic births not long after the Big Bang. These “hot off the press” computer models include some new wrinkles. They take into account previously neglected interactions between dark matter and the primordial “stuff” of the Universe. That would be hydrogen and helium gas. The result of the simulations: tiny, bright galaxies that formed more quickly than in computer models that didn’t include those motions. Now astronomers just need to find them, using JWST, in an effort to see if their theories of dark matter hold up.

How would interactions between baryonic matter and dark matter make a difference? Here’s one likely story: in the early Universe, clouds of gas moved at supersonic speeds past clumps of dark matter. It bounced off the dark matter. Eventually, after millions of years, the gaseous material fell back together to form stars in a blast of star birth. The team’s simulations track the formation of those galaxies right after the Big Bang.

A composite model of matter distribution in the Universe (with dark matter overlay) in a galaxy formation simulation made by the TNG Collaboration.

Naoz’s team thinks that the existence of those smaller, brighter, more distant galaxies could confirm the so-called “cold dark matter” model. It suggests that the Universe was in a hot dense state containing only gases after the Big Bang. Over time, it evolved to a lumpy distribution of galaxies (and eventually galaxy clusters). Along the way, stars and galaxies formed, but the earliest steps likely depend on gravitational interaction with dark matter. If the supersonic interactions that Naoz’s team modeled actually happened, then those little galaxies would be the result.

According to our predominant cosmological models, Dark Matter makes up the majority of mass in the Universe (roughly 85%). While it is not detectable in visible light, its influence can be seen based on how it causes matter to form large-scale structures in our Universe. Based on ongoing observations, astronomers have determined that Dark Matter structures are filamentary, consisting of long, thin strands. For the first time, using the Subaru Telescope, a team of astronomers directly detected Dark Matter filaments in a massive galaxy cluster, providing new evidence to test theories about the evolution of the Universe.

The team consisted of astronomers from the Department of Astronomy and the Center for Galaxy Evolution Research (CGER) at Yonsei University and the Department of Physics and Astronomy at the University of California Davis (UC Davis). Their results appeared in a paper, “Weak-lensing detection of intracluster filaments in the Coma cluster,” on January 5th, 2024, in Nature Astronomy. As the team explained, Subaru revealed the terminal ends of dark matter filaments in the Coma Cluster spanning millions of light years.

Hubble Space Telescope offers a cosmic cobweb of galaxies and invisible dark matter in the cluster Abell 611. Credit: ESA/Hubble, NASA, P. Kelly, M. Postman, J. Richard, S. Allen

Our accepted cosmological models predict that galaxy clusters grow at the intersection of Dark Matter filaments that make up the large-scale structure of the Universe (“cosmic web”) and extend for tens of millions of light-years. While this hypothesis is supported by observations of the distribution of galaxies and gas (i.e., baryonic or “visible” matter) in the Universe, there have been no direct detections of the dark matter component of intracluster filaments (ICFs) until now. Using the Subaru Telescope, the Yonsei-led team searched for signs of dark matter filaments in the Coma Cluster.

This cluster is located 321 million light-years away in the direction of the constellation Coma Berenices and contains over 1,000 identified galaxies. It is also one of the largest and closest galaxy clusters, which makes it a good candidate for looking for faint signs of Dark Matter. However, its proximity also makes it difficult to observe the entire cluster. But thanks to the Subaru Telescope’s combination of high sensitivity, high resolution, and wide field of view, the team was able to detect weak-lensing effects that indicated the presence of ICFs in the Coma Cluster.

NASA’s Plankton, Aerosol, Climate, ocean Ecosystem (PACE) satellite successfully launched and reached on Thursday, February 10th. The mission took off from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida, at 1:33 am EST 10:33 pm (PST) atop a SpaceX Falcon 9 rocket. About five minutes after launch, NASA confirmed that ground stations on Earth had acquired a signal from the satellite and were receiving data on its operational status and capabilities post-launch. For the next three years, the mission will monitor Earth’s ocean and atmosphere and study the effects of climate change.

Specifically, PACE was designed to study how the ocean and atmosphere exchange carbon dioxide and how microscopic particles (aerosols) in our atmosphere might fuel phytoplankton growth in the ocean. The data it accumulates will be used to identify the extent and duration of harmful algae blooms and extend NASA’s long-term observations of our changing climate. As NASA Administrator Bill Nelson expressed in an agency press release:

“Congratulations to the PACE team on a successful launch. With this new addition to NASA’s fleet of Earth-observing satellites, PACE will help us learn, like never before, how particles in our atmosphere and our oceans can identify key factors impacting global warming. Missions like this are supporting the Biden-Harris Administration’s climate agenda and helping us answer urgent questions about our changing climate.”

The PACE satellite deploying in orbit. Credit: NASA

The satellite will perform oceanic measurements using its hyperspectral ocean color instrument, allowing researchers to study oceans and bodies of water in the visible, ultraviolet, and near-infrared wavelengths. This will enable scientists to track the distribution of phytoplankton and determine which communities are present on a daily, global scale from space. This will be a first for scientists and coastal resource managers, who will use the data to forecast the health of fisheries, track harmful algal blooms, and identify changes in the marine environment.

Although supermassive black holes are common throughout the Universe, we don’t have many direct images of them. The problem is that while they can have a mass of millions or billions of stars, even the nearest supermassive black holes have tiny apparent sizes. The only direct images we have are those of M87* and Sag A*, and it took a virtual telescope the size of Earth to capture them. But we are still in the early days of the Event Horizon Telescope (EHT), and improvements are being made to the virtual telescope all the time. Which means we are starting to look at more supermassive black holes.

The latest observations focus on a black hole region known as 3C 84, or Perseus A. It is a radio-bright source in a galaxy more than 200 million light-years away. Even the latest iteration of the EHT can’t resolve the horizon glow of the black hole as we’ve done with M87* and Sag A*, but it can see the bright region surrounding the black hole, where magnetic fields are particularly intense.

The 3C 84 black hole is located in the galaxy NGC 1275, which is part of the Perseus cluster. The galaxy is not just distant, it also has a central region rich in dust, which shrouds the black hole. Optical light can’t penetrate the region, but radio light can. The Event Horizon Telescope can also capture the polarization of radio light coming from the area. This is important because charged particles within a strong magnetic field emit polarized light. By mapping this polarization astronomers can study magnetic fields.

One focus of this work is to see how supermassive black holes can generate powerful jets that stream from the black hole at nearly the speed of light. Magnetic fields are key. As ionized matter falls into a black hole it can bring with it strong magnetic fields. These fields can pin to the accretion disk of a black hole, which intensifies fields in the region that it becomes difficult for the black hole to capture more matter. This is known as a magnetically arrested disk.

One idea is that as the magnetically arrested disk rotates around the black hole, magnetic field lines become twisted, winding ever tighter and trapping magnetic energy. The release of this energy through magnetic realignment could power the formation of ionized jets. While such a magnetic realignment hasn’t been observed, this study shows that we might be able to capture such an event.

On January 21st, 2024, a meter-sized asteroid (2024 BX1) entered Earth’s atmosphere and exploded over Berlin at 12:33 am UTC (07:45 pm EST; 04:33 pm PST). Before it reached Earth, 2024 BX1 was a Near-Earth Asteroid (NEA) with an orbit that suggests it was part of the Apollo group. The fragments have since been located by a team of scientists from the Freie Universität Berlin, the Museum für Naturkunde (MfN), the German Aerospace Center (DLR), the Technische Universität Berlin, and the SETI Institute and identified as a rare type of asteroid known as “aubrites.”

The name aubrites comes from the village of Aubrés in France, where a similar meteorite fell on September 14th, 1836. The team responsible for recovering samples of this latest meteorite was led by SETI Institute meteor astronomer Dr. Peter Jenniskens and MfN researcher Dr. Lutz Hecht. They were joined by a team of staff and students from the MfN, the Freie Universität Berlin, the DLR, and the Technische Universität Berlin days after the meteor exploded in the sky. Together, they found the meteor fragments in the fields just south of the village of Ribbeck, about 50 km (31 mi) west of Berlin.

Aubrite meteorite from asteroid 2024 BX1, photographed at the Museum für Naturkunde Berlin by Laura Kranich, a Freie Universität MSc student and member of the Arbeitskreis Meteore, who participated in the search and found this meteorite near the village of Ribbeck, Germany. Credit: SETI Institute

Finding the fragments was a major challenge because of the peculiar appearance of aubrites, which resemble rocks like any other from a distance but are quite different to look at up close. Whereas other types of meteors have a thin crust of black glass caused by the extreme heat generated by passing through the atmosphere, aubrites have a mostly translucent glass crust. Christopher Hamann, a researcher from the Museum für Naturkunde, was involved in the initial classification and participated in the search. As he related in a SETI Institute press release:

“Aubrites do not look like what people generally imagine meteorites to look like. Aubrites look more like a gray granite and consist mainly of the magnesium silicates enstatite and forsterite. It contains hardly any iron and the glassy crust, which is usually a good way to recognize meteorites, looks completely different than that of most other meteorites. Aubrites are therefore difficult to detect in the field.”

The number of near misses, false starts, and legitimate disasters that have befallen our species since the day we took our first upright steps all those generations ago is too large to count and could honestly take up this entire book. I’ll give us humans this much, though: we’re survivors, through and through.

We are, to put it bluntly, remarkable. There is nothing in this cosmos that even begins to approach anything resembling the complexity of the human brain. There is no other world that we have discovered, within our solar system or without, that can support the dizzying array of chemical reactions that we call life, let alone consciousness.

Sure, with enough planets around enough stars within enough galaxies, life is probably bound to happen one way or another, but it appears that life only happened here, once, billions of years ago, when it didn’t appear – or was snuffed out – even in our own solar backyard.

Even our planet is special. Take a look at the other planets of the solar system. If doesn’t matter if you’re using a backyard telescope or the latest NASA robotic gear, the answer is always the same. While every planet looks and acts (and probably smells) different from all the rest, they all share one thing in common: they’re dead.

Lifeless. Uninhabitable. Inhospitable. Barren balls of cold rock. Barren balls of molten rock. Barren balls of exceedingly hot rock buried under thick layers of atmosphere. Barren.

A recent study published in The Astrophysucal Journal Letters discusses the detection of water within the atmosphere of GJ 9827 d, which is a Neptune-like exoplanet located approximately 97 light-years from Earth, using NASA’s Hubble Space Telescope (HST), and is the smallest exoplanet to date where water has been detected in its atmosphere. This study was conducted by an international team of researchers and holds the potential to identify exoplanets throughout the Milky Way Galaxy which possess water within their atmospheres, along with highlighting the most accurate methods to identify the water, as well.

For the study, the researchers analyzed data using Hubble’s Wide Field Camera 3 (WFC3), which is a fourth-generation ultraviolet imaging spectrograph (UVIS)/Infrared (IR) imager that replaced the Wide Field Planetary Camera 2 during Servicing Mission 4, which was conducted by STS-125 in May 2009 and was the fifth and final servicing mission for Hubble. The researchers used WFC3 to observe 11 transits of GJ 9827 d, which orbits its star in 6.2 days, over a period of three years and identified what they hypothesize to be water within the exoplanet’s atmosphere. While the team stops short at confirming the existence of water, they eliminated the likelihood that the results were from starspots after analyzing data from NASA’s Kepler/K2 mission.

Image of NASA’s Hubble Space Telescope, which is about the size of a school bus, obtained by the STS-125 crew on May 19, 2009, after completion of Servicing Mission 4. (Credit: NASA)

“This would be the first time that we can directly show through an atmospheric detection that these planets with water-rich atmospheres can actually exist around other stars,” said Dr. Björn Benneke, who is an Associate Professor and the Head of the Astronomy Group within the Department of Physics at Université de Montréal and lead author of the study. “This is an important step toward determining the prevalence and diversity of atmospheres on rocky planets.”

While the team does not definitively confirm the existence of water within GJ 9827 d’s atmosphere, they do have a series of competing hypotheses pertaining to how and why water could exist: the atmosphere is rich in hydrogen like most gaseous planets but with traces of water, which the team was fortunate enough to detect; or GJ 9827 d is a rocky planet surrounded by a water vapor envelope. However, the team notes that recent studies of GJ 9827 d have suggested it could lose more than half of its atmosphere over the course of one billion years, meaning GJ 9827 d isn’t likely to possess an atmosphere dominated by hydrogen.

Proxima Centauri B is the closest exoplanet to Earth. It is an Earth-mass world right in the habitable zone of a red dwarf star just 4 light-years from Earth. It receives about 65% of the energy Earth gets from the Sun, and depending on its evolutionary history could have oceans of water and an atmosphere rich with oxygen. Our closest neighbor could harbor life, or it could be a dry rock, but is an excellent target in the search for alien life. There’s just one catch. Our usual methods for detecting biosignatures won’t work with Proxima Centauri B.

Most exoplanets are discovered through the transit method, where a planet regularly passes in front of its star from our point of view. We see the recurring dip in a star’s brightness, and we know the planet is there. For transiting exoplanets, we can look for changes in the spectrum of the star as the planet transits. Some of the starlight passes through an exoplanet’s atmosphere, and some wavelengths get absorbed by the atmosphere. By looking at the pattern of absorption, we can fingerprint different molecules. This is how we’ve detected the presence of water, carbon dioxide, and other molecules in exoplanet atmospheres.

But Proxima Centauri B isn’t a transiting planet. It was discovered by a different method known as Doppler spectroscopy. When we look at the light from Proxima Centauri, we can see its spectrum redshift and blueshift slightly over time. The gravitational pull of Proxima Centauri B makes the star wobble slightly. So we know the exoplanet is there, and have a good idea of its size and mass, but since it doesn’t transit its star we can’t observe its atmospheric absorption spectrum.

But a new study argues there is another way we might find life, using the reflection of starlight off the planet’s atmosphere. In principle the idea is simple. Rather than looking for light passing directly through the atmosphere, look instead for light that has reflected off the planet directly. We’ve done this for planets such as Mars and the outer planets, which don’t transit the Sun, so we could do it for exoplanets as well.

The problem is that reflected starlight from a planet is tiny compared to the radiance of the star itself. Detecting the reflected light of a planet is like capturing the light of a firefly flittering near the edge of a spotlight. So astronomers have used masks to block the central brilliance of a star and see its family of planets. We have done this to directly observe large gas planets orbiting stars, but not Earth-sized worlds.

All stars form in giant molecular clouds of hydrogen. But some stars are extraordinarily massive; the most massive one we know of is about 200 times more massive than the Sun. How do these stars gain so much mass?

Part of the answer is that they form in multiple star systems.

Astronomers have thought for a long time that massive stars are born in multiple stellar systems. They form as twins, triplets, quadruplets, or even larger sibling groups. Massive stars, defined as stars with more than eight stellar masses, are the progenitors of supernovae, neutron stars, and black holes. That’s why researchers are so keen on understanding their origins.

Astrophysicists have a strong theoretical knowledge of how stars form, and they’ve constructed detailed simulations of stellar formation. Those simulations show how massive stars form in a hierarchical process. Giant clouds collapse to form dense cores. In those “parent cores,” smaller regions collapse into individual stars: some massive and some not so massive. Astronomers think that our Sun formed as one of the less massive stars in this hierarchical process. They’ve even tracked down the Sun’s siblings.

Developing strong theories that describe Nature is a critical part of astronomy. But scientists have a healthy caution for something that remains theoretical. It takes observations to show how well theories match reality, and observations of multiple stars forming are difficult to obtain.

Fifty-five million light years from Earth there is a massive elliptical galaxy known as Messier 87, or M87 for short. It was cataloged by Charles Messier in the 1700s, along with 102 other fuzzy objects in the sky that were definitely not comets. It was confirmed to be a galaxy in the early 1900s, and by the mid-twentieth century, it was known to be a powerful radio source. But these days it is most widely known for the supermassive black hole deep in its core. Called M87*, it is the first black hole directly observed by astronomers. The first image of M87* was released in 2019, and was based on observations taken by the Event Horizon Telescope (EHT) in 2017. Now a new image based on 2018 data has been released. The similarities and differences between the two images tell us a great deal about M87* and black holes in general.

Although the Event Horizon Telescope has a single name, it is actually a collaboration of radio telescopes across the world. The observations of each observatory are combined through a process of interferometry to create an Earth-sized virtual telescope. Although the name stays the same, the EHT has improved over time with the addition of new equipment and even new telescopes. For example, the 2018 data included the Greenland Telescope (GLT), which did not participate in the 2017 run.

Because of this change between different data runs, each run is effectively a new observation with a new telescope. Since the 2017 and 2018 data sets are theoretically uncorrelated, astronomers can compare the two to see which features of the black hole have remained the same, and which have changed.

One major similarity is that the size of the central shadow is the same for both images. This shadow is caused by background light from the center of M87 being focused toward us by the black hole. Since the size of the shadow depends on the size of the black hole’s event horizon, this confirms that the original estimation of the black hole’s size and mass was correct and that it hasn’t changed over time. This is important because there was some criticism that the original image relied too heavily on simulations to pull out its features from the data. We can now verify that the EHT imaging software is correct. We really can observe black holes directly.

One interesting difference easily seen in the images is that the bright region of the ring has shifted counterclockwise by about 30 degrees. This is due to the accretion disk of the black hole. As the disk swirls around the black hole, its orientation wobbles, the bright spot of the ring to shift. Astronomers predicted this effect, now confirmed by the data. The amount of shift over the course of a year is consistent with the predicted orientation of the black hole’s rotation, which should have its rotational axis aligned along the powerful jet that streams away from M87.

This strange-looking galaxy seems to be a spiral with a long tidal tail stretching away. It’s known as Arp 122, and it’s actually not just one galaxy, but two separate galaxies. NGC 6040 is the warped spiral galaxy seen edge-on, while LEDA 59642 is the round, face-on spiral. The two are colliding about 540 million light-years from Earth, and it gives us a preview of the Milky Way’s future collision with Andromeda.

This image was taken by the venerable Hubble Space Telescope

What will Arp 122 look like when the merger is complete? We’ll try to keep you posted, but this ongoing merger will take hundreds of millions of years, so be patient.

While galactic mergers incredibly dramatic and energetic events, they occur at a snail’s pace, just because of the massive distances involved. But still, even a slow-motion collision can create chaos and grandeur. Star formation begins to ramp up from collisions of gas clouds and extreme gravitational interactions. Usually, the merged galaxies can shine up to ten times brighter than they did individually. Over time, this completely changes the structure of the two (or more) colliding galaxies, usually results in a single, merged galaxy.

The collisions can also create stellar features called tidal tails, like the one seen in Arp 122, or in the Mice Galaxies, above. The tails can look like streams or arcing rivers of stars moving along in the wake of the collision. Other features can be created that look like ripples, similar to how ripples form when you toss a rock into a pond. Astronomers have learned how to interpret the different features to learn more about the original galaxies and their collisions.  

Maybe Mars isn’t as dry as we thought. ESA’s Mars Express has revealed new details about a region near Mars’ equator that could contain a massive deposit of water ice several kilometers deep. If it is indeed ice, there is enough of it in this one deposit that if melted, water would cover the entire planet up to 2.7 meters (almost 9 feet) deep.

But ice is just one explanation for the unusual features detected by the orbital spacecraft. Another is that this is a giant pile of dust several kilometers deep — although the dust would still need to have some ice mixed in.

Mars Express has been orbiting Mars since December of 2003 and back in 2007, the spacecraft studied the Medusae Fossae Formation (MFF), a large geological formation that includes wind-sculpted ridges and grooves, abrupt mesas, interspersed with smooth and gently undulating areas. The region extends intermittently for more than 5,000 km (3,100 miles) along the equator of Mars, extending from just south of Olympus Mons to Apollinaris Patera, with a smaller additional region closer to Gale Crater, where the Curiosity rover is exploring.

Various spacecraft in addition to Mars Express, such as NASA’s Mars Global Surveyor and Mars Odyssey, have also detected subsurface ice, as much as 2.5 km (1.5 miles) deep.

Now, new data from Mars Express suggest layers of water ice stretching even further underground – the most water ever found in this part of the planet.

Mars is the next frontier of human space exploration, with NASA, China, and SpaceX all planning to send crewed missions there in the coming decades. In each case, the plans consist of establishing habitats on the surface that will enable return missions, cutting-edge research, and maybe even permanent settlements someday. While the idea of putting boots on Martian soil is exciting, a slew of challenges need to be addressed well in advance. Not the least of which is the need to locate sources of water, which consist largely of subsurface deposits of water ice.

Herein lies another major challenge: Martian ice deposits are contaminated by toxic perchlorates, potent oxidizers that cause equipment corrosion and are hazardous to human health (even at low concentrations). To this end, crewed missions must bring special equipment to remove perchlorates from water on Mars if they intend to use it for drinking, irrigation, and manufacturing propellant. This is the purpose of Detoxifying Mars, a proposed concept selected by the NASA Innovative Advanced Concepts (NIAC) program for Phase I development.

The lead developer of this concept is Lynn Rothschild, a Senior Research Scientist at NASA’s Ames Research Center (ARC) and the Research and Technology Lead for the Science and Technology Mission Directorate (STMD) at NASA HQ. As she and her colleagues noted in their proposal, the “scale of anticipated water demand on Mars highlights the shortcomings of traditional water purification approaches, which require either large amounts of consumable materials, high electrical draw, or water pretreatment.”

Graphic depiction of Detoxifying Mars: the biocatalytic elimination of omnipresent perchlorates. Credit: Lynn Rothschild

Perchlorates (ClO4-) are chemical compounds that contain the perchlorate ion, which form when chlorine compounds become oxidized. Perchlorate salts are kinetically stable, very soluble, have a low eutectic temperature (the lowest possible temperature they can achieve before freezing), and become very reactive at high temperatures. Chlorate (ClO3-) salts are similar, though they are less kinetically stable than perchlorates. Perchlorates were first detected on Mars by the Wet Chemistry Laboratory (WCL) instrument on the Phoenix mission, which landed in the northern Vastitas Borealis region in May 2008.

The very early Universe was a dark place. It was packed with light-blocking hydrogen and not much else. Only when the first stars switched on and began illuminating their surroundings with UV radiation did light begin its reign. That occurred during the Epoch of Reionization.

But before the Universe became well-lit, a specific and mysterious type of light pierced the darkness: Lyman-alpha emissions.

Even though the early Universe was too dark for light to travel through the opaque gas that dominated it, astronomers have still detected some Lyman-alpha lines prior to the lights coming on in the Epoch of Reionization. Where did it come from? That’s been a significant unanswered question that many have pondered.

Lyman-alpha emissions occur in the UV range and come from hydrogen atoms as their electrons transition to a specific energy state. Lyman-alpha spectral lines are part of what astronomers call the Lyman-alpha forest. The forest is a series of absorption lines stemming from the hydrogen in distant astronomical objects. As their light passes through gas clouds with different redshifts, it creates the forest of Lyman-alpha lines.

“Providing an explanation for the surprising detection of Lyman-alpha in these early galaxies is a major challenge for extragalactic studies,” the authors of some new research write.