Will Titan finally answer, ‘Are we alone?’

We recently examined how and why Jupiter’s moon, Europa, could answer the longstanding question: Are we alone? While this small icy world gives plenty of reasons to believe why we could—and should—find life within its watery depths, it turns out our solar system is home to a myriad of places where we might find life. Much like how the Voyager missions gave us the first hints of an interior ocean swirling beneath Europa’s outer icy shell, it was only fitting that Voyager 1 also gave us the first hints of the potential for life on Saturn’s largest moon, Titan, as well.

“Titan is fascinating because it is so far away from Earth, so cold, and made of such different materials on the surface that it should be impossible to understand,” says Dr. Jani Radebaugh, a Professor in the Department of Geological Sciences at Brigham Young University whose research focuses on Titan. “But we find that Earth-like landscapes are there in abundance – rivers, lakes, mountains, wind-swept deserts, and my favorite – giant dunes like in the Sahara Desert.”

Despite Voyager 1’s cameras being unable to penetrate Titan’s thick atmosphere, it successfully gathered data on Titan’s surface temperature and air pressure, with some scientists previously conjecturing that Titan might contain lakes of liquid hydrocarbons due to the moon’s extremely cold temperatures and abundance of methane. While this well-known component of carbon and hydrogen exists in a gaseous form here on Earth, methane can also exist in liquid form in extremely cold temperatures, much like Titan. Voyager also confirmed that Titan contained traces of ethane, propane, acetylene, and other organic molecules, with its atmosphere comprised largely of nitrogen. Organic molecules are considered the simple building blocks of life, which is why Titan is so intriguing for the field of astrobiology and finding life beyond Earth.

While NASA’s Cassini spacecraft provided us infrared images of Titan’s surface, which revealed hydrocarbon seas and moving sand dunes, it wasn’t until the European Space Agency’s (ESA) Huygens probe landed on the surface of Titan in January 2005 that we got our first up-close views of the surface of this mysterious moon. It was through these images that we confirmed evidence of recent surface liquid activity due to the abundance of rounded pebbles within the images.

Infrared composite image of Titan taken by Cassini in November 2015. (Credit: NASA/JPL/University of Arizona/University of Idaho)

Colorized image of Titan’s surface originally taken by the Huygens probe after landing on the surface in January 2005. The globules seen are (possibly) made of water ice and range in size from 10-15 cm (4-6 in). (Credit: ESA/NASA/JPL/University of Arizona; processed by Andrey Pivovarov)

“At a bare minimum, we think that life requires: (1) energy, (2) water, and (3) carbon,” says Dr. Jason Barnes, who is a Professor in the Department of Physics at the University of Idaho. “Solar and geothermal energy abound throughout the solar system, so the energy part isn’t rare. We used to think that water was rare, but now we recognize several Ocean Worlds in the outer solar system with voluminous oceans. Carbon, however, seems to be quite rare—at least in usable form (i.e., not CO2).  Titan’s carbon chemistry complexity is second only to Earth’s, and we don’t yet know the extent of it even!”

Both NASA’s Cassini and ESA’s Huygens probe gave scientists a treasure trove of data about Titan to pour over for years to come, but it’s NASA’s upcoming Dragonfly mission that promises to be the real gamechanger in the hunt for life on Saturn’s largest moon. The goal of this dual-quadcopter will be to literally “hop” to various locations on Titan searching for biosignatures on its frigid surface throughout its two-year mission, which is scheduled to launch in 2027 and arrive at Titan in 2034.

Artist’s rendition of NASA’s Dragonfly exploring the Titan’s surface. (Credit: NASA)

Dr. Barnes, who is also the Deputy Principal Investigator of Dragonfly, says he couldn’t be more excited for the mission.

“It’s going to be an adventure of a lifetime,” he says. “Dragonfly’s biggest contribution to our knowledge of Titan’s habitability will come from our measurements of chemistry. Cassini measurements of Titan’s chemistry ended at molecular weight of 100 – not because Titan’s molecules ended there, but because the mass range of our instruments ended there. And that was way up high in the atmosphere, too, not on the surface. So, Dragonfly will land on the surface and ingest both (1) organic sediments, and (2) water ice. Together, we hope to learn how far organic chemistry has progressed on Titan, and indeed whether it has progressed to the point of prebiotic chemistry or life itself.”

With the Huygens probe sitting frozen on Titan’s surface, its batteries having lasted for only 90 minutes, and Cassini intentionally burning up in Saturn’s atmosphere at the end of its respective mission in 2017, for now we wait for Dragonfly to liftoff into history. But while we wait, we wonder.

We wonder what kinds of life we might find on Titan, on either its surface or the depths of its liquid methane lakes.

“Because Titan contains all the right molecular ingredients for life, coupled with the presence of solar or internal heat energy and liquid water from volcanoes or impact craters, it may just be the perfect place for life to have formed,” explains Dr. Radebaugh. “Since we haven’t seen this yet outside Earth, it’s hard to know exactly what is required for life to succeed, but if we start with those basic requirement premises and then just go take a look, we will learn a lot about the viability of life in the solar system and across the universe.”

And with this, we wonder if Titan will finally answer, “Are we alone?”

As always, keep doing science & keep looking up!

Featured Image: Natural color image of Titan taken by Cassini in January 2012. (Credit: NASA/JPL-Caltech/Space Science Institute)

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China’s Zhurong Rover Looks Deep Underground and Sees Layers From Multiple Floods on Mars

Mars exploration has been ongoing for decades at this point, and some regions of the planet have become more interesting than others. Of particular interest is a basin known as Utopia Planitia. It was the site of the Viking-2 landing, one of the first-ever successful missions to Mars. From data collected during that mission, scientists developed a theory that the crater that formed Utopia might have been the site of an ancient ocean. New results from China’s Zhurong rover point to an even more exciting past – repeated flooding.

Zhurong has been exploring the red planet for a little over a year and has primarily been moving around Utopia Planitia. One of its instruments, a ground penetrating radar, is providing the world with the first data on the subsurface structure of Utopia since Viking-2 was shut down in 1980.

The picture that radar is painting is an interesting one. It appears that there are several layers beneath the surface of Utopia Planitia. The regolith, which is most commonly thought of as Martian dirt, only extends to about 10 meters below the surface.

UT discusses the China vs NASA Mars race.

Below that is where things get interesting – a paper just published in Nature by researchers at the Chinese Academy of Sciences points to several different sub-layers beneath the regolith. They also point to a potential cause – flooding.

That’s not to say that there is any active flooding going on. In fact, Zhurong found no evidence of liquid water anywhere within the basin’s top 80 meters of material. However, the layered structure the rover noticed could easily have been caused by repeated flooding events.

The research team thought those events might have occurred in the Late Hesperian or Amazonian period, which followed the Late Heavy Bombardment that formed many of Mars’ modern craters, and ended about 3 billion years ago. Back then, liquid water was thought to be extant on Mars’ surface, though it also signaled the beginning of the end of that liquid water on the surface.

An image from China’s Zhurong rover shows spacecraft hardware in the foreground and Martian terrain in the background.
Credit: CNSA

Some of that liquid water might have ended up sloshing around in Utopia Planitia, though. And the best way to detect it would be to find layers such as those found by Zhurong. Though the CAS research team quickly points out that there could be other possible explanations and invites public comment on their work.

If assisted by Occam’s razor, that work points to a pattern of flooding in the Utopia basin billions of years ago. But new evidence could always overturn those assumptions. If the recent history of Mars exploration is any indication, Zhurong will sure not be the last visitor to this particularly interesting basin.

Read More:
Chinese Academy of Sciences – Insights into Utopia Basin Revealed by Mars Rover Zhurong
Li et al – Layered subsurface in Utopia Basin of Mars revealed by Zhurong rover radar
UT – Mars Orbiter Captures Images of China’s Rover From Space
UT – Is there Water Under Mars’ South Pole?

Lead Image:
Self of Zhurong rover and its landing platform.
Credit – CNSA / Xinhua

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Mars Rocks Have the Right raw Ingredients to 3D Print Everything From Tools to Rocket Parts

3D printing will be an absolutely critical technology as space exploration starts to take off. Initially, it will be impossible to individually manufacture every tool needed to create and sustain infrastructure in space. The only option will be to build some of those tools in space itself, in no small part, because it could potentially take months or even years to get to any area where the tools are manufactured. So any tool that can be created in situ is the best option available for early space explorers. Using materials like Martian regolith to 3D print those tools has long been an area of ongoing research. Now a team from Washington State University has successfully printed some tools using simulated Martian regolith, and they seem to work – up to a point.

The team, led by Professor Amit Bandyopadhyay of WSU’s Mechanical and Materials Engineering Department, used a powder-based 3D printing method to combine simulated Martian regolith. Martian regolith is a black, powdery substance designed to mimic materials found on the surface of the red planet with a powdered titanium alloy.

Combinations of materials ranging from only 5% regolith up to 100% regolith were tested. They were subjected to a sintering process that saw them heated to 2,000 degrees C and then allowed to cool while forming different shapes and sizes of solid material.

Showcasing 3D printing using Martian regolith.
Credit – Washington State University YouTube Channel

Testing the resultant ceramics was a mixed bag. Samples made of the 100% Martian regolith were brittle and developed cracks in their structure as part of the printing process. While those cracks would prove a deal-breaking for tool manufacturing, such cracks are relatively inconsequential for other use cases on the Martian surface, such as adding a layer of radiational protection to human habitats, which Dr. Bandyopadhyay and his team are quick to point out.

Lower concentrations of regolith (and consequently higher concentrations of titanium) performed better in terms of the material properties necessary for tool-making. In fact, the mixture of 5% regolith with 95% titanium actually resulted in superior physical properties to tools that were made with simply 100% titanium.

The press release from WSU doesn’t explain why that might be the case, but it points to a potential use case for Martian regolith as a significant component of tools used by future Martian explorers. And as the press release does make clear, every saved kilogram of material that doesn’t have to be launched is potentially hundreds of thousands of dollars saved.

Mars isn’t the only place 3D printing with regolith could prove useful. Artist’s impression of a lunar base created with 3D printing techniques.
Credits: ESA/Foster + Partners

We’ve reported numerous times that printing using regolith isn’t a novel idea. We’ve also reported how in-situ resource utilization can get messy sometimes. This isn’t even the first time Dr. Bandyopadhyay’s team has 3D printed something with regolith – they were part of a NASA study ten years ago that looked at using crushed lunar regolith as a feed material for a 3D printing process.

There’s still lots of work to be done before any tool is used to fix anything on Mars, but proving it could be made even partially with materials native to the Red planet is a step towards making it a reality. And the team at WSU is undoubtedly not the last group that will look at making even better tools out of those materials.

Read More:
WSU – Martian rock-metal composite shows potential of 3D printing on Mars
UT – Swarms of Robots Could Dig Underground Cities on Mars
UT – Five Teams Compete to Design a 3D Printed Mars Habitat for NASA

Lead Image:
Mars depiction
Credit – Wasan Prunglampoo via iStock, with credit to NASA

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Two “Super Mercury” Exoplanets Found in a Single System

There’s a star system out there with three super-Earth planets and two super-Mercuries. Super-Earths are fairly familiar types of exoplanets, but super-Mercuries are rare. Those are planets with the same composition as our own Mercury, but larger and denser. Yet, here’s HD 23472, showing off two of eight known super-Mercuries in the galaxy.

A team of researchers at the Instituto de Astrofisica e Ciencias do Espaco in Portugal discovered these two dense inner planets. Their study is focused on small exoplanets and their compositions, and how position, temperature, and the properties of their stars affect them. The team chose HD 23472 as a candidate to study exoplanets and the transition between having or not having an atmosphere. It could be related to the evaporation of an atmosphere by irradiation from the parent star.

The discovery of two super-Mercuries in the system was unexpected, according to team leader Susana Barros. “The team found that this system is composed of three super-Earths with a significant atmosphere and surprisingly, two Super-Mercuries, which are the closest planets to the star,” she said.

This artist’s concept shows a five-exoplanet system similar to the one being studied. At HD 23472, however, there are two Super-Mercuries orbiting the star. Courtesy NASA Ames/Kepler/K2 Mission.

What’s a Super-Mercury and Why so Rare?

To get a handle on these rare planets, take a look at our own Mercury. It orbits closest to the Sun. So do these two planets. Structurally, it’s quite dense, as these super-Mercuries are. What we don’t know is their internal structure. If they’re like our Mercury, then they should each have a molten inner core as it does. In our Mercury, that core is surrounded by a solid iron sulfide outer core. A relatively thin crust made of silicate rocks lies at the top. Mercury also has a magnetic field. The temperature on its surface ranges up to 700 K (427 C), although the poles remain out of the sunlight and very cold.

Basically, it’s a small overheated planet. And, Mercury has no atmosphere but does have an “exosphere”. That’s a thin sheath of atoms of hydrogen, helium, oxygen, calcium, and others. It doesn’t hang around long and gets carried off by the solar wind, which also feeds the exosphere. Atoms of other elements come from the surface or are delivered by cometary impacts (in the case of water vapor).

Mercury’s desiccated, overheated appearance is due to its proximity to the Sun. It might have had a more substantial mantle and crust early in its history. But, that likely got blasted off by impacts. Mercury is a rarity even in our own solar system. And, scientists didn’t expect to see many of them around other stars. Yet, they’re out there. Do they have similar interior characteristics to our own Mercury? And, could their histories be similar? Those questions remain to be answered.

How Do Super-Mercuries Form? It’s Still an Open Question

Barros’s team’s discovery of two super-Mercuries has some promising areas of research—and some puzzles. “For the first time we have discovered a system with two super-mercuries,” she said. “This allows us to obtain clues about how these planets were formed, which could help us exclude some possibilities. For example, if an impact large enough to create a Super-Mercury is already very unlikely, two giant impacts in the same system seem very improbable. We still don’t know how these planets are formed but it appears to be connected to the composition of the parent star. This new system can help us find out”.

All planets form in the clouds of gas and dust that orbit their newborn parent stars. Planet formation is a complex process, and each system has its own quirks and idiosyncrasies. Some of those quirks come from the composition of the parent star; others from the chemical composition and structure of the protoplanetary disk—the birth crêche—of the planets. It’s important to know more about how planets grow from tiny seeds to finished worlds within those clouds. Finally, scientists have to take into account interactions between planets in a forming system.

Team member Olivier Demangeon explained that understanding how two Super-Mercuries could form in the standard planet-crêche environment also requires more information about the composition of the finished worlds. “As these planets have radii smaller than the Earth, current instrumentation does not have the sensitivity to probe the composition of their surface or the existence and composition of a potential atmosphere,” he said. There’s still a great deal of information to gather about this system, including the birth stories of its two Super-Mercuries.

A Census of HD 23472

Here’s what the team does know. Of the five planets in the HD 23472 system, three have masses smaller than the Earth. These are among the lightest exoplanets whose masses were measured using the radial velocity method. That measurement was only possible due to the very high precision of the ESPRESSO instrument. That stands for Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations), installed in ESO’s Very Large Telescope (VLT), in Chile. The presence of not one, but two super-mercuries in its data, left the team wanting to go further.

In the meantime, big questions remain: did the Super-Mercuries form in much the same way that our Mercury did? If so, what are the chances of multiple giant impacts transforming these worlds at HD 23472? Will exoplanet hunters find more of them out there?

The team hopes eventually to use the Extremely Large Telescope (ELT) and its first-generation high-resolution spectrograph to make the observations. Both instruments will have the sensitivity and precision to help characterize the composition of planets like those orbiting HD 23472.

For More Information

Two rare super-mercuries discovered around the same star

HD 23472: a multi-planetary system with three super-Earths and two potential super-Mercuries

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A Computer Algorithm is 88% Accurate in Finding Gravitational Lenses

Astronomers have been assessing a new machine learning algorithm to determine how reliable it is for finding gravitational lenses hidden in images from all sky surveys. This type of AI was used to find about 5,000 potential gravitational lenses, which needed to be confirmed. Using spectroscopy for confirmation, the international team has now determined the technique has a whopping 88% success rate, which means this new tool could be used to find thousands more of these magical quirks of physics.

“These lenses are very small so if you have fuzzy images, you’re not going to really be able to detect them,” said Dr. Kim-Vy Tran, from the ARC Centre of Excellence for All Sky Astrophysics in 3-Dimensions (ASTRO3D) and the University of NSW (UNSW), who led the study. “Our spectroscopy allowed us to map a 3D picture of the gravitational lenses to show they are genuine and not merely chance superposition.”

Pictures of gravitational lenses from the AGEL survey.  The pictures are centred on the foreground galaxy and include the object name.  Each panel includes the confirmed distance to the foreground galaxy (zdef) and distant background galaxy (zsrc). Credit: ARC Centre of Excellence for All Sky Astrophysics in 3-Dimensions (ASTRO3D) and the University of NSW (UNSW).

Scientists say that gravitational lenses could transform our ability to chart the evolution of galaxies since the Big Bang. This type of lensing occurs when light from a distant object is distorted by a closer massive object along the same line of sight. This distortion effectively creates a giant lens which magnifies the background light source, allowing astronomers to observe objects embedded within those lens-created arcs and rings that are otherwise be too far and too dim to see.

Gravitational lenses are a great tool for astronomy. Not only do gravitational lenses reveal distant objects like galaxies, but it can also provide information about how far away these galaxies are. Additionally, analyzing the nature of gravitational lensing patterns tells astronomers about the way dark matter is distributed within galaxies. It also provides a way to investigate both the development of structure in the universe and the expansion of the universe.

The machine learning algorithm was pioneered by Colin Jacobs at Swinburne University in Australia. He used the technique to sift through tens of millions of galaxy images to prune the sample down to 5,000. Other surveys, like dark energy surveys, have also been used to find lensing candidates.

Tran and colleagues assessed 77 of the 5,000 candidate lenses using the Keck Observatory in Hawai’i and Very Large Telescope in Chile. They confirmed that 68 out of the 77 are strong gravitational lenses spanning vast cosmic distances. This suggests that the algorithm is reliable enough to find thousands of new gravitational lenses. To date, gravitational lenses have been hard to find and only about a hundred are routinely used.

“Never did we dream that the success rate would be so high,” said professor Karl Glazebrook from Swinburne, and co-Science Lead on the paper, in a press release. “Now we are getting images of these lenses with the Hubble Space Telescope, they range from jaw-droopingly beautiful to extremely strange images that will take us considerable effort to figure out.”

The work is part of the ASTRO 3D Galaxy Evolution with Lenses (AGEL) survey. Tran said their goal now with AGEL is to spectroscopically confirm around 100 strong gravitational lenses that can be observed from both the northern and southern hemispheres throughout the year.

The team’s paper was published in the Astronomical Journal.

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A Single High-Resolution Image of Dimorphos Stacked From DART’s Final Images

Here’s a sharper view of Dimorphos, the small asteroid moonlet that the DART (Double Asteroid Redirection Test) spacecraft intentionally crashed into. Eydeet on Imgur created a higher resolution image of Dimorphos by stacking the last few images received from the spacecraft before impact.

First impressions? It’s an egg-shaped rubble pile.

Made a “high res” image of Dimorphos by stacking the last images received from DART

What we know:

Dimorphos is about 160 meters (530 feet) in diameter and it orbits a larger, 2,560-foot (780-meter) asteroid called Didymos. This asteroid duo makes the perfect target for this demonstration test, as NASA says the impact should change the way Dimorphos orbits Didymos. DART crashed into the asteroid at roughly 22,530 km/hr (14,000 mph), which is expected to have slightly slowed the asteroid’s orbital speed. One NASA scientist explained, the impact was “like ramming a golf cart into the Great Pyramid.”

Scientists are now poring over the data to determine how much the orbit was changed. This will show if DART’s 570 kilograms (1,260-pounds) of impact is a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered.

The orbit of Didymos and Dimorphos ranges from just outside the orbit of Earth (about 1 AU) to a bit beyond the orbit of Mars (about 2.27 AU. It takes 2.11 years for the pair to make a trip around the Sun.

The following tweets provide some info about the scale of what we see up close on Dimorphos:

I used AI upscaling and sharpening to reprocess the final full-frame image from #DARTmission DRACO cam of the asteroid's surface 2 seconds / 12 km before impact. Added a scale bar. It's a rubble pile! (Source: https://t.co/qjNa54ZPnt) pic.twitter.com/umOz59nM9B

— Jason Major (@JPMajor) September 27, 2022

DIMORPHOS vs TESLA ROADSTER, TO SCALE

Starman's Tesla Roadster (4 m long), found parked on Dimorphos, conveniently provides scale.@NASA @JHU_APL #DART @SETIInstitute @SpaceX @SpaceX360 #Tesla #Dimorphos #Starman pic.twitter.com/qSdkidSpgT

— Pascal Lee (@pascalleetweets) September 27, 2022

Didymos is classified as a member of the Amor group of asteroids, which are near-Earth asteroids with orbits outside the orbit of Earth and inside of Mars’ orbit.  

Didymos spins rapidly – rotating about once every 2.26 hours. The moonlet revolves around the larger body about once every 11.9 hours. The main asteroid and its moonlet orbit each other about 1 kilometer (0.62 miles) apart.

DART launched on November 24, 2021, and after 10 months of flying about 11 million kilometers (7 million miles) through space, it caught up with Dimorphos.

The DART team has said they expect the impact to shorten Dimorphos’ orbit by about 1 per cent, or roughly 10 minutes; precisely measuring how much the asteroid was deflected is one of the primary purposes of the full-scale test. Some of the early indications from images taken by both ground-based and space telescopes are that the impact appeared to be larger than expected. More details from the telescopes will be coming out in the coming weeks and months, so it may be some time before we know precisely how much DART’s impact altered Dimorphos’ the asteroid’s orbit around Didymos.

Further reading:
More info on Didymos and Dimorphos from NASA
NASA’s Planetary Defense Coordination Office

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A Dwarf Galaxy Passed Close to the Milky Way and Left Ripples in its Wake

When you imagine the collision of galaxies, you probably think of something violent and transformational. Spiral arms ripped apart, stars colliding, cats and dogs living together, mass hysteria. The reality is much less dramatic. As a recent study shows, our galaxy is in a collision right now.

Although the big collision between the Milky Way and the Andromeda Galaxy is still yet to come, our galaxy has undergone galactic collisions in the past. The most well-understood collision is that between the Milky Way and the Sagittarius Dwarf Galaxy. This small galaxy first impacted the Milky Way about 6 billion years ago and may have triggered the star-forming period that produced our Sun.

History of the Sagittarius dwarf galaxy collision. Credit: ESA

But collisions on a galactic scale are slow and tedious. Over billions of years, the core of the Sagittarius galaxy has struck the Milky Way a few times as it is gradually ripped apart. It can now be seen as arcs of stars encircling our galaxy. It stands to reason that such an ancient collision is long over, but this recent study shows it still has ripple effects on the Milky Way. Literally.

The team used data from the Gaia spacecraft and looked at the motion of stars near the outer edge of the Milky Way. The velocities of these stars showed a rippled distribution of motion, created by Sagittarius the way a dropped stone might trigger ripples on a pond. Overall the stars at the outer edge of the Milky Way are not in gravitational equilibrium, which is a fancy way of saying our galaxy is still feeling the effects of the collision.

The team was surprised by the level of detail the Gaia data provided. By measuring the positions of more than two billion stars, and the motions of more than 30 million, Gaia has given the team a kind of galactic seismology that can be used to trace the dynamic history and evolution of the Milky Way.

Galactic collisions are dramatic on cosmic scales. They are a central process of galactic evolution that can trigger star formation, black hole mergers, and the formation of large elliptical galaxies. But as this latest work shows, on a human scale, it’s all just another day for life on Earth.

Reference: McMillan, Paul J., et al. “The disturbed outer Milky Way disc.” Monthly Notices of the Royal Astronomical Society 516.4 (2022): 4988–5002.

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Stars Spiral Inward to the Cores of Stellar Nurseries

Astronomers studying a stellar cluster within the Small Magellanic Cloud (SMC) have found young stars spiraling in towards the center of the cluster. The cluster, NGC 346, is an open cluster embedded within a glowing cloud of gas, which is typical of stellar nurseries – places where new stars are formed. The outer spiral arm of this star forming region appears to be funneling gas, dust and new stars into the center, which researchers describe as an efficient way to fuel the birth of new stars.

The SMC is a small satellite galaxy of the Milky Way, visible with the naked eye to Southern hemisphere observers under dark skies. It is about 200 000 light years away, and contains a number of nebulae and clusters. One of these, NGC 346, combines a population of bright, new stars, and their still-collapsing stellar nursery of gas and dust, which continues to produce new stars.

The region is only 150 light years across, and has a mass of about 50 000 Suns. Its unusually high rate of star-formation, and its intriguing shape, have been an interesting puzzle to astronomers for some time. This latest image offers some fresh clues to help us understand what’s going on. It combines observations from the Hubble Space Telescope (HST) and the European Southern Observatory’s (ESO) Very Large Telescope (VLT).

NGC 346: Star Forming Cluster in the SMC. Image Credit & License: NASA, ESA, Hubble; Processing: Judy Schmidt

Elena Sabbi of the Space Telescope Science Institute in Baltimore, and leader of the study, had this to say:

“Stars are the machines that sculpt the Universe. We would not have life without stars, and yet we don’t fully understand how they form. We have several models that make predictions, and some of these predictions are contradictory. We want to determine what is regulating the process of star formation, because these are the laws that we need to also understand what we see in the early Universe.”

Sabbi and her team used a series of HST images taken over the course of 11 years to calculate the movements of the stars within the NGC 346 cluster. By comparing this sequence of images, they were able to measure the movements of stars within the cluster. Over the 11 years, the stars moved an average of 320 billion kilometers, slightly more than twice the distance from the Earth to the Sun. This works out to a surprisingly slow speed of only 3200 kilometers per hour. The HST produces a particularly high image resolution, and is extraordinarily accurate, making these measurements possible.

Meanwhile, a second team used the Multi Unit Spectroscopic Explorer (MUSE) instrument on the VLT, to take measurements of the radial velocities of the same stars. The team, led by Peter Zeidler of AURA/STScI for the European Space Agency, use the spectrographic instrument to measure the speeds at which those stars are moving towards or away from Earth.

“What was really amazing is that we used two completely different methods with different facilities and basically we came to the same conclusion independently,” said Zeidler. “With Hubble, you can see the stars, but with MUSE we can also see the gas motion in the third dimension, and it confirms the theory that everything is spiraling inwards.”

This spiral motion seems to arise naturally, as it is the easiest and most efficient way for material to make its way to the high-density central regions of the nebula.

“A spiral is really the good, natural way to feed star formation from the outside towards the center of the cluster,” explained Zeidler. “It’s the most efficient way that stars and gas fueling more star formation can move towards the center.”

The SMC is useful to physicists trying to understand star formation because it has a much simpler chemical composition than our own galaxy, and so better matches the conditions of the early universe. The simpler chemistry of stars formed at that time caused them to burn hotter and faster, and having an environment in our galactic backyard that matches those conditions is very handy for scientists. By observing stars of different ages in the various stellar nurseries in the SMC, we can better understand the burst of star formation that is believed to have occurred throughout the Universe when it was just a few billion years old.

These latest observations tell us that star formation in this early period happened in a way that is very similar to how modern stars form right now in our own Milky Way.

“The Hubble archive is really a gold mine,” said Sabbi. “There are so many interesting star-forming regions that Hubble has observed over the years. Given that Hubble is performing so well, we can actually repeat these observations. This can really advance our understanding of star formation.”

The next step is to repeat these observations with the NASA/ESA/CSA James Webb Space Telescope (JWST). JWST will be able to resolve smaller, cooler stars than what were included in the current measurements. Over time, researchers will be able to repeat the observations, including the lower mass stars. This will serve to confirm and verify the current work, and expand upon it to include more of the stellar population. This will allow a comparison of the behavior of high and low mass stars, and bring a more complete understanding of the dynamics of these stellar nurseries.

https://www.esa.int/ESA_Multimedia/Images/2022/09/Spiralling_stars_provide_a_window_into_the_early_Universe

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The Moon was Pummeled by Asteroids at the Same Time the Dinosaurs Died. Coincidence?

It only takes a quick look at the Moon to see its impact-beaten surface. There are craters everywhere. Some of those impact sites apparently date back to the same time some very large asteroids were whacking Earth. One of them formed Chixculub Crater under the Yucatan Peninsula. That impact set in motion catastrophic events that wiped out much of life on Earth, including the dinosaurs.

Did some of the craters on the Moon form from the same asteroid swarm that impacted Earth and precipitated the demise of the dinosaurs? Chang’e 5 samples from specific craters on the Moon seem to show that this could well have happened.

That’s the conclusion a group of Australian scientists came to after studying glass beads from the Moon. They outlined their findings in a paper about the science they performed on samples picked up from the Moon by the Chang’e 5 Lunar mission. The beads were created by the heat and pressure caused by meteoritic impacts on the Moon. The lead author of the paper, Professor Alexander Nemchin, from Curtin University’s Space Science and Technology Centre (SSTC) in the School of Earth and Planetary Sciences, said the findings imply that the timing and frequency of asteroid impacts on the Moon may have been mirrored on Earth. If so then the find tells us more about the history of the evolution of our own planet.

“We combined a wide range of microscopic analytical techniques, numerical modeling, and geological surveys to determine how these microscopic glass beads from the Moon were formed and when,” Professor Nemchin said. “We found that some of the age groups of the lunar glass beads coincide precisely with the ages of some of the largest terrestrial impact crater events, including the Chicxulub impact crater responsible for the dinosaur extinction event.”

Glass beads collected by the Chang’e 5 mission date back some 66 million years and could have formed from impacts. Courtesy Beijing SHRIMP Center, Institute of Geology, CAGS

Looking at the Earth/Moon Asteroid Bombardment Coincidence

The team looked at the idea that large impacts, such as the Chixculub event, were accompanied by smaller impacts. The event that led to Chixculub’s formation happened about 66 million years ago. If the “big one” aimed at Chixculub had company, then it’s a good idea to look at the Moon, too. The ages and frequencies of impacts on the Moon around the same time might give clues to bombardments on Earth and the other inner solar system planets.

The death of the dinosaurs is one of the most fascinating stories to spring from Earth’s ancient geological history. The story goes (and there’s geological evidence to back it up) that an impact was certainly part of the story. Some 65 million years ago, Earth was basking in the Cretaceous period. Dinosaurs had been roaming the planet for about 165 million years. They still reigned across the globe along with some of the earliest mammals and other forms of life. However, the number of dinosaur species was starting to shrink. At the same time, some pretty severe volcanic eruptions were affecting Earth’s atmosphere and surface.

That Asteroid Likely Had Company

The asteroid that set off the extinction, not just of dinosaurs, but other species, left behind evidence. It’s in the form of a layer of iridium in geological strata around the world. That layer dates back to around 66 million years ago. Asteroids are rich in iridium. Finding it provided “smoking gun” evidence something from space helped hasten the demise of 75 percent of life on Earth way back then. At the same time the Chicxulub impactor hit, something excavated several other craters around the planet. This suggests that multiple impactors—possibly from the same parent asteroid—smacked into Earth, too. So, it’s not a big leap to find evidence of impacts on the Moon from objects in the same asteroid swarm.

Co-author Associate Professor Katarina Miljkovic, also from Curtin’s SSTC, said future comparative studies of the lunar samples could also add to our store of knowledge about the Moon’s geological history. “The next step would be to compare the data gleaned from these Chang’e-5 samples with other lunar soils and crater ages to be able to uncover other significant Moon-wide impact events which might, in turn, reveal new evidence about what impacts may have affected life on Earth,” she said.

So, the death of the dinosaurs and the mysterious glass beads are likely related. They both speak to a larger bombardment event that involved both Earth and the Moon.

For More Information

Lunar glass shows Moon asteroid impacts mirrored on Earth

Constraining the formation and transport of lunar impact glasses using the ages and chemical compositions of Chang’e-5 glass beads

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DART Impact Seen by Hubble and Webb

What happens when you whack a little asteroid with an even littler spacecraft? People around the world watched on the 26th of September when the DART mission smashed into the side of Dimorphos. This tiny worldlet is a companion asteroid to Didymos. It was the world’s first test of the kinetic impact technique, using a spacecraft to deflect an asteroid by modifying its orbit. Amateur observer networks and professional observatories tracked the meetup from the ground. In a first, both Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST) took simultaneous images and data.

Together, they managed to track the asteroid before the event. Then, they got images and data about the ejecta (the material that got flung away from it) afterward. Each set of images showed streaks of ejecta stretching out away from the little asteroid. Scientists could even tell exactly where the spacecraft hit the asteroid. The data should tell them about the asteroid’s composition and structure. Eventually, they should find out how much the impact affected Dimorphosis’s orbit.

Doin’ it with DART

The collision of spacecraft and an asteroid posed a challenge for observers. That’s because Dimorphos and its companion Didymos move fairly quickly in their orbits. Ground-based observers were able to track the faint objects fairly well, and networks of smaller telescopes caught a view of the collision and its aftermath.

For JWST, tracking that action isn’t exactly what the telescope was built for, but the teams managed. Flight operations, planning, and science teams for JWST had to come up with a method to track the asteroids. They actually move faster than JWST was originally programmed for, so that had to be taken into account. JWST watched the event using its Near-Infrared Camera (NIRCam). Webb observed the impact over five hours total and captured 10 images.

JWST captured this sequence of the DART collision on Dimorphos. Courtesy NASA, ESA, CSA, and STScI.

HST had a little easier time of it since it successfully tracked comets, asteroids, and planets throughout its history. The telescope captured 45 images in the time immediately before and following DART’s impact with Dimorphos.

An animated view captured by Hubble Space Telescope. NASA, ESA, CSA, and STScI

The Work Continues

In the coming months, scientists will also use Webb’s Mid-Infrared Instrument (MIRI) and Near-Infrared Spectrograph (NIRSpec) to make more observations of Dimorphos. Hubble will monitor Dimorphos ten more times over the next three weeks to monitor how the ejecta cloud from the collisions expands and fades over time.

The DART mission isn’t the first spacecraft to encounter a small solar system body. Recall, for example, the Rosetta mission, which crash landed on Comet 67P/Churyumov-Gerasimenko. More recently, the OSIRIS-REx mission touched down briefly on asteroid Bennu to capture samples for future study. Hayabusa2 returned samples after a brief encounter with asteroid Ryugu and is on its way to study other asteroids within this decade.

Hera Follows Dart

ESA’s Hera mission will head to Dimorphos in 2024 to see what DART did to this little world. Courtesy ESA/Science Office

The European Space Agency is sending its Hera mission to Dimorphos in 2024 to do a post-impact study. It will be the first probe to rendezvous with a binary asteroid system and examine the aftermath of DART’s kinetic impact test. The idea is to see how well an asteroid deflection mission could work, in the event that one is headed directly for Earth.

The DART and Hera missions are in the vanguard of asteroid deflection studies. The threat of asteroid collisions on our planet is very real, and both NASA and ESA have worked together to develop asteroid monitoring networks. The next steps, which began with DART and will continue with HERA, will find ways to avert the threat of impact.

For More Information

Webb and Hubble capture detailed views of DART impact
The Hera Mission

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NASA and SpaceX Will Study Low-Cost Plan to Give Hubble a Boost

NASA and SpaceX say they’ll conduct a feasibility study into a plan to reboost the 32-year-old Hubble Space Telescope to a more sustainable orbit, potentially at little or no cost to NASA.

The plan could follow the model set by last year’s Inspiration4 mission, an orbital trip that was facilitated by SpaceX and paid for by tech billionaire Jared Isaacman as a philanthropic venture. Isaacman, who is now spearheading a privately funded space program called Polaris in cooperation with SpaceX, says he’ll participate in the feasibility study.

“We could be taking advantage of everything that’s been developed within the commercial space industry to execute on a mission, should the study warrant it, with little or no potential cost to the government,” Isaacman said at a news briefing.

If the six-month feasibility study turns into an actual mission, a spacecraft could be sent up to Hubble to lift the telescope from its current altitude of 330 miles to the 370-mile orbit it was in when it was deployed in 1990. Patrick Crouse, Hubble project manager at NASA’s Goddard Space Flight Center, said that could add another 15 to 20 years to the telescope’s life.

But if the study finds that the reboost mission would be unrealistic, NASA would have to come up with a way to deorbit or dispose of the 12-ton telescope safely in the 2030 time frame, Crouse said.

Hubble has far exceeded its projected operating life of 15 years, thanks in part to a series of servicing missions that were conducted by visiting crews of shuttle astronauts. When NASA retired the space shuttle fleet in 2011, it was thought that there’d be no more service calls — and that Hubble would go through a slow, steady decline.

But today Thomas Zurbuchen, NASA’s associate administrator for science, pointed out that Hubble was “healthy” and “doing great science.” He noted, for example, that the telescope’s team was part of a global campaign to observe this week’s climax to the DART asteroid-smashing mission.

“Frankly, Hubble is more exciting than ever, because it now is a complementary asset next to the James Webb Space Telescope in a different frequency range, with a different viewpoint,” Zurbuchen said.

It’s too early to say whether additional servicing might be done on the telescope. “It’s all on the table now,” said Jessica Jensen, vice president of customer operations and integration at SpaceX.

Jensen and Zurbuchen portrayed the mission as an opportunity to demonstrate technologies that could be applied to other space science projects in near-Earth orbit.

Isaacman said the idea of visiting Hubble came up during discussions about tasks that could be accomplished during a future Polaris mission. The program’s first mission, Polaris Dawn, is due to send the billionaire and three other spacefliers into orbit in a SpaceX Crew Dragon capsule sometime next year. Polaris Dawn’s mission plan includes a spacewalk.

Although the Space Act agreement for the Hubble feasibility study announced today is just between NASA and SpaceX, the space agency says other commercial space ventures would be given a chance to do similar studies and submit parallel proposals. Northrop Grumman, for example, has already demonstrated a robotic system for reboosting satellites in Earth orbit. But if SpaceX and Isaacman follow through on suggestions that their mission would fly at little or no cost to NASA, other companies might find it difficult to match that offer.

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The First Telescope Images of DART's Impact are Starting to Arrive

On September 26th, at 23:14 UTC (07:14 PM EST; 04:14 PM PST), NASA’s Double Asteroid Redirect Test (DART) spacecraft successfully struck the 160-meter (525 ft) moonlet Dimorphos that orbits the larger Didymos asteroid. The event was live-streamed all around the world and showed footage from DART’s Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) as it rapidly approached Dimorphos. In the last few seconds, DART was close enough that individual boulders could be seen on the moonlet’s surface.

About 38 seconds after impact, the time it took the signal to reach Earth, the live stream ended, signaling that DART had successfully impacted Dimorphos and was destroyed in the process. Meanwhile, teams of astronomers stretching from the Indian Ocean to the Arabian Peninsula watched the impact with their telescopes. One, in particular – the Les Makes Observatory on the island of Le Reunion in the Indian Ocean – captured multiple images of the impact. These were used to create a real-time video and show the asteroid brightening as it was pushed away, followed by material ejected from the surface.

The observation campaign was organized by the ESA’s Planetary Defence Office (PDO) and coordinated by the Agency’s Near-Earth Object Coordination Centre (NEOCC). This campaign was one of several worldwide that coincided with DART’s successful test of the kinetic impact method. While not all observation stations were successful due to cloud cover, technical problems, and other issues, the ESA campaign acquired several stunning images showing the kinetic impactor hitting its target and what immediately followed.

“Something like this has never been done before, and we weren’t entirely sure what to expect,” said Marco Micheli, an Astronomer at the NEOCC. “It was an emotional moment for us as the footage came in.”

As you can see from the video (posted above), the asteroid immediately started brightening upon impact and was many times brighter within seconds. This indicated that the moonlet’s trajectory was altered, causing more sunlight to be reflected from its surface. Less than a minute after impact, a cloud of ejected material became visible as it drifted into the path of direct sunlight and began reflecting it. The time-lapse video shows (in thirteen seconds) what took place over roughly half an hour. As Dora Föhring, another NEOCC astronomer, adds: 

“This was the conclusion of weeks of discussions, meetings, accurate planning and observational design by our team, together with local observers and scientists at all our collaborating stations. This fantastic campaign has produced data that our astronomers, together with the whole DART collaboration, will now begin to analyse to extract valuable scientific information on the effects of the impact.” 

To determine how much the moonlet’s orbit has been altered, astronomers will measure its light curve over time using ground-based telescopes. Observations will also be made using space-based telescopes, including the venerable Hubble and the James Webb. This data will be used to calculate any changes in Dimorphos’ period as it continues to orbit Didymos, which will confirm that the kinetic impact method is an effective means of altering the trajectory of asteroids and preventing them from impacting Earth.

The ESA also plans to mount a follow-up mission with the Hera mission, which will launch in October of 2024 and rendezvous with the double-asteroid system in December 2026. Once it arrives, Hera will be the first spacecraft to rendezvous with a double-asteroid system and perform a detailed post-impact survey. Ian Carnelli, the Hera Mission Manager, said:

“The results from DART will prepare us for Hera’s visit to the Didymos binary system to examine the aftermath of this impact a few years from now. Hera will help us understand what happened to Dimorphos, the first celestial body to be measurably moved by humankind, and ultimately to protect ourselves from space rocks that could one day do the same.” 

Further Reading: ESA

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Robots Might Jump Around to Explore the Moon

How great are wheels, really? Wheels need axles. Suspension. Power of some kind. And roads, or at least swaths of relatively flat and stable terrain. Then you need to maintain all of it. Because of their cost many civilizations across human history, who knew all about wheels and axles, didn’t bother using them for transportation. Another way to look at it – much of human technology mimics nature. Of the simple machines, levers, inclined planes, wedges, and even screws are observed in nature. Why not the wheel?

The main competition to wheels are legs, which to be fair are also a total nightmare. Whether using the wetware of a horse’s brain or the software of an Atlas robot, legs mean greater demand for computing power to maintain balance under different conditions and loads. Plus the “suspension” gets super complex, often requiring a spine or similar structure that is prone to single-point failure.

So how about jumping? It can take fewer moving parts than rolling or walking, saving weight and removing points of failure. While balancing becomes more critical, it also becomes simpler. Low obstacles become nearly as insignificant as level terrain. And most surfaces you can walk on or roll over, you can also bounce on. The biggest issue is the explosive power required, but even this is being addressed with strategies like stutter jumping.

How common are hopping robots?

There have been many successful jumping robot technology demonstrators, like Salto, LSJR, and prototypes from of MIT’s Leg Lab and Sandia Lab’s Intelligent Systems and Robotics Center. More common today are robots which can, but do not exclusively, jump, like Sand Flea, RHex, and Festo’s Kangaroo. And in the world of toys, jumping robots can be mailed to your home with just a few clicks.

Do you need legs to jump? Not really. Ever played with a “jumping popper?” Researchers at Harvard’s Wyss Institute have successfully combined this technology with…explosions and 3-D printing. Another strategy is to gradually spin up and abruptly stop internal flywheels, which comically but effectively flings the rover in a desired direction.

Space Jumping

Since robot jumping is old hat here on Earth, has it been tried on other celestial bodies? Yes! A hopping rover was first launched by the Soviet Union as part of the Fobos 2 mission in 1988, but communication was lost before the PROP-F rover could be deployed on Mars’ largest moon. The first robot to successfully hop on another celestial body was a second-generation MIcro/Nano Experimental Robot Vehicle for Asteroid (MINERVA-II). Three MINERVA rovers arrived at the asteroid Ryugu in September of 2018 aboard JAXA’s Hayabusa2 spacecraft and successfully jumped around the asteroid using flywheels. Also aboard was the French-German Mobile Asteroid Surface Scout (MASCOT-1), which basically took the technology that your phone uses to vibrate when it gets a text and dialed it up to eleven. MASCOT’s internal “swing arm” allowed it to flip over to make sure its instruments were all pointed in the right direction, and make “mini-moves” over Ryugu’s surface.

But flywheels and swing arms probably won’t work everywhere. Ryugu has a surface gravity of about 1/80,000 of what we experience here on the surface of the Earth. Our Moon’s surface gravity is about 1/6 as strong as Earth’s, but about 13,000 times stronger than Ryugu’s. This makes slipping a greater risk. And unlike Ryugu, the Moon’s boulder fields feature relatively large rock fragments scattered across a smooth, sometimes steep, powdery surface. Given the need for ground clearance, agility, good footing, and sudden powerful movements, jumping on the Moon will probably be done by legs. Why reinvent the wheel, right? So to speak.

Apollo 16 Commander John Young jumps off the lunar surface to salute the American flag, photographed by Lunar Module Pilot Charlie Duke. Credit: NASA Video

ESA calls for ideas

In May of 2020 the European Space Agency (ESA) opened a Call For Ideas for Moon missions that could be delivered with a European Large Logistic Lander (EL3). One of the Topical Teams selected for further development, headed by Hendrik Kolvenbach of ETH Zürich, proposed a mission for the Legged Exploration of the Aristarchus Plateau, or LEAP.

An early-model ANYmal demonstrates its hopping ability. In lunar gravity ANYmal could jump several meters high. Credit: ETH Zürich/Robotics Systems Labs (RSL)

Aristarchus Plateau is a geologically diverse region of the Moon, which is a nice way of saying that it has lots of steep hills and boulders. Goldmine for science, minefield for wheeled rovers. The LEAP team identified a suitable platform in ANYmal, a fully autonomous quadrupedal robot. Initially developed by ETH Zürich’s Robotic Systems Lab, ANYmal can walk, run, and jump, but in testing has relied increasingly on walking and loping gaits to navigate simulated low-gravity environments. The LEAP team recently presented their progress to date at the 2022 Europlanet Science Congress (EPSC).

The LEAP rover trains using Reinforcement Learning in a simulation of the lunar terrain typical of Aristarchus Plateau. Slopes, rocks, friction, and gravity are relatively easy to simulate. Loose, granular regolith  is more challenging to simulate and is handled with real-world trials. Credit: ETH Zürich/ETH Zürich/Robotics System Lab (RSL)

Bounding out of the Uncanny Valley

Other robots developed at ETH Zürich have been more specialized for jumping, namely SpaceBok and SpaceHopper. Both show promise in simulated ultra-low gravity environments like what you’d find on Ryugu or similar asteroids and small moons. Ultimately we will likely see a next generation of hopping robots with greater precision than MINERVA or MASCOT, gathering data from what used to be inaccessible moons and asteroids and learning about the early formation of our solar system.

SpaceBok demonstrates its jumping ability. Credit: Robotic Systems Lab

SpaceHopper tests its jumping and reorientation abilities in simulated lunar gravity. Credit: SpaceHopper

Will the future of space roving have wheels? Almost certainly. But we now live in a solar system where helicopters fly on two worlds. And soon Earth may not be the only celestial body with submarines. The next age of exploration comes with options. Jumping robots will open steep hills, boulder fields, and precarious perches to scientific inquiry like never before. And let’s be honest, some of these rovers are absolutely adorable.

For More Information

• A Survey of Bioinspired Jumping Robots, published in Applied Bionics and Biomechanics
• Summary of LEAP presentation at Europlanet Science Congress (EPSC) 2022
• ETH Zürich’s Robotic Systems Lab’s ANYmal information page
• ANYbotics’ ANYmal information page

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Innovation to combat space debris – Chinese scientists introduce drag sail

Scientists at the Shanghai Academy of Spaceflight Technology (SAST) have devised an ingenious way to combat the growing problem of space debris. The team fitted a drag sail to a Long March 2 rocket and successfully launched it in July this year. Rocket launches often leave discarded booster stages in low-earth orbit, adding to the pollution of near-earth space. The pilot testing for the sail came as a surprise to many space agencies when, a day after the rocket’s launch, the 25 square meters deorbiting sail was unfolded.

To understand how the sail works, it helps to have an idea of the type of collateral debris that is generated every time a rocket is sent into space. It takes a lot of fuel to shoot heavy objects high enough out of the atmosphere to reach orbital space. These fuel tanks are heavy and must be discarded as soon as they are empty, so that the rocket can reach it’s intended altitude. These empty stages, and other discarded parts like payload adaptors, are left behind and orbit the earth until they eventually de-orbit and break up as they re-enter. However, this process can take many years, and so the volume of space debris is growing rapidly.

The growing debris orbiting earth threatens very real risk to operational space craft in LEO

The way the drag sail works is to create friction against the thin upper atmosphere, which slows the payload adaptor down in the course of its orbital journey. As we know from high-school physics, objects that contend with more atmospheric resistance, will slow down faster and come back to ground sooner. The drag sail is made of a fine, durable membrane that unfurls to create drag, and increase the speed at which the object will de-orbit.   

Although it has long been theorised, the successful deployment of this sail represents a breakthrough as this new technology may help to solve the mounting “space-junk” problem in Earth’s low orbit. The less time debris spends in orbit, the lower the chance it has of hitting an active satellite and creating a chain reaction. It also presents companies and organisations with an affordable option to “clean up behind themselves” in future.

If you consider that LEO (Low-Earth orbit) is already facing a crisis of tiny objects and artifacts speeding around the planet, every new launch means that we’re adding to the problem. In fact, the issue is so big now that there are dedicated teams at multiple agencies that specifically track every piece that is currently in orbit. According to the European Space Agency, the individual bits of junk number approximately 31,650 individual objects to date. What makes it worse is that they can only track items above a certain size. Estimates of smaller bits of paint, metal, and glass number in the millions. There is data that suggests that there could be up to 130 million objects between 10cm and 1mm orbiting the globe right now. As it is, the International Space Station (ISS) has had to perform 25 evasive maneuvers since 1999 to avoid catastrophic damage. If you’re wondering what that might look like, the 2013 Alfonso Cuarón film “Gravity” provides a dramatized depiction of the chain-reaction that might occur when an active spacecraft is hit by even tiny objects, travelling at 20 to 30 thousand kilometers per hour.  

Space junk orbiting around earth – A conceptual depiction of pollution around our planet

Space junk isn’t a new threat by any means. Multiple projects are in development to address the issue, and there are teams from across the globe who are working on a way to clear the immediate orbital space above our atmosphere. This sense of urgency is due to the large number of communications satellites that are set to be launched in the very near future. There are many private companies that have set high goals on achieving “full-earth-connectivity” even in remote places, and the only way to achieve that is to send hundreds of satellites into space. It is unlikely that this trend will slow down, because even the most conservative projections promise an exponential “space object” growth rate in the very near future. That means more debris with every single new launch. What makes the innovation of the sail so unique is the fact that although there are organisations working towards a strategy to do a proper “clean-up” of the zone, there have been few that address the problem from a point of long-term sustainable space preservation. The AstroScale and ClearSpace Today projects have both shown promise in cleaning up the existing “dump” that we’ve created. The sail adds to the overall solution. It is the application of both approaches that will make the best long-term impact. If we can clean up existing space junk, and then ensure minimal debris from future de-orbits, we stand a chance of creating a sustainable and viable environment in our orbital space.

There have been calls to declare orbital space an ecologically protected environment, with a strong focus on the long term affects to our atmosphere, observational astronomy, and long-term scientific research. The space science community are calling for companies and countries to establish a “debris footprint” convention, similar to the current Carbon footprint.  

Get more news about SAST here

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Alaska Has New Lakes. Unfortunately, They’re Releasing a lot of Methane

A NASA scientist is finding newly formed lakes in Alaska that are belching greenhouse gases at a high rate. The main one is methane, a gas many people use in their natural gas-fueled grills. She’s tracking these emissions in one of Earth’s most remote regions—the Arctic. It has millions of lakes, many of them hundreds or thousands of years old. But, only the youngest of them are releasing high amounts of methane. And that is due to the effects of climate change on these delicate environments.

Katey Walter Anthony is an ecologist at the University of Alaska-Fairbanks working with NASA to study this region. She points out that the appearance of younger, methane-belching lakes is a harbinger of things to come. “So that’s a concern for the future, when we think about permafrost carbon feedback, are areas that are newly thawed,” she said.

One of Walter Anthony’s jobs is to sample the gas content at the lakes in the region using methane collection devices that bob on the surface of the water. The bottles will be taken to the lab and the gas analyzed. But, in the field there’s a quick way to tell how much methane is in the lake: simply light a match at the end of the bottle’s valve. A flame flares out in the presence of methane, almost like lighting a camp stove.

Turning the valve on a bubble trap in Big Trail lake releases methane gas, which is flammable. Holding a match near the valve ignites the gas in a burst of flame. Credit: NASA / Sofie Bates

Climate change and Permafrost Thaw = More Methane

Walter Anthony has been studying Big Trail Lake in Alaska. It’s a good example of a methane-rich thermokarst lake that formed less than 50 years ago, she said. Big Trail is one of several at the focus of NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) project which looks at how quickly climate change is affecting the Arctic regions. The “symptoms” of this change are reduced Arctic sea ice, thawing of permafrost soils, decomposition of long-frozen organic matter, widespread changes to lakes, rivers, coastlines, and alterations of ecosystem structure and function. The ABoVE project has been conducting an airborne campaign since 2017 as part of NASA’s Terrestrial Ecology program. It studies parts of Alaska and Western Canada.

Young lakes like Big Trail Lake are harbingers of things, says Walter Anthony as she tracks the formation of thermokarst in general. She is looking at how the changing climate will cause more of these lakes to form as more permafrost melts. “Lakes like Big Trail are new, they’re young, and they are important because these lakes are what’s going to happen in the future,” she explained.

Forming a Thermokarst Lake

Big Trail was created as subsurface permafrost thawed. As that underground ice melted, the ground it was frozen into collapsed and formed a watery sinkhole. The fine details are more complex. When a permafrost layer thaws beneath lakes, things start to happen. In general, microbial activity increases, and pathways form in the permafrost. At Big Trail Lake and others in the region, the microbes digest dead plants and other organic matter in the previously frozen soil in a process that produces carbon dioxide and methane.

Sometimes, permafrost thaw can form long empty tubes or ‘chimneys’ under lakes. These allow methane and other gases trapped deep underground to escape. This release of ‘geologic’ methane into the atmosphere is also happening at Esieh Lake, another of Katey Walter Anthony’s ABoVE study sites.

“At Big Trail Lake, it’s like opening your freezer door for the first time and giving all the food in your freezer to microbes to decompose. As they decompose it, they are belching out methane gas,” she pointed out.

Methane bubbles appear on the surface of Big Trail Lake. Credit: NASA / Sofie Bates

The Seasonal Freeze-Thaw Cycle Also Traps and Releases Methane

As the lakes freeze in the winter, methane bubbles prevent ice from forming. That creates areas of open water that allow methane to escape throughout the season. In other areas, the methane bubbles create frozen domes of ice on the surface of a lake. It’s a natural process, but over the past few decades, it has been accelerated by climate change and warmer Arctic temperatures.

“Once the ice has formed on these lakes, the rising methane bubbles will freeze into the ice,” explains Franz Meyer, Chief Scientist at the Alaska Satellite Facility in Fairbanks. Meyer is also one of the chief scientists for NISAR, a joint NASA and ISRO satellite that will study our planet—and the Arctic, in particular—using airborne radar. It’s a challenging mission, part of NASA’s larger interest in tracking methane from space, the air, and the ground.

“These bubbles that we see in the ice change the way that the radar signal interacts with the ice surface,” he explained. Radar waves bouncing off the surface of a lake or the land can detect roughened areas. Some of that roughness comes from the methane bubbles just under the surface. A thermokarst lake with a high roughness likely has methane content in its bubbles. And, the science team finds that they tend to have higher methane emissions than smooth lakes. Combining the airborne radar data with measurements collected in the field allows scientists to estimate how much methane lakes are emitting across a large region.

The formation of new thermokarst lakes will continue as global climate change raises temperatures. The Arctic regions like the ones that Walter Anthony is studying are almost functioning like “canaries in the coal mine”. Their higher-than-normal emissions will continue to pump greenhouse gases into the atmosphere, enhancing future cycles of melting and methane release.

For More Information

Alaska’s Newest Lakes Are Belching Methane

Arctic Sea Ice News
ABoVE

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