Friday, May 3, 2024

Starlink on Mars? NASA Is Paying SpaceX to Look Into the Idea

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

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

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

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

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

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

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

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

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

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

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

The post Starlink on Mars? NASA Is Paying SpaceX to Look Into the Idea appeared first on Universe Today.



Did You Hear Webb Found Life on an Exoplanet? Not so Fast…

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

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

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

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

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

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

Eddie Schwieterman, astrobiologist, University of California, Riverside

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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



Thursday, May 2, 2024

The Highest Observatory in the World Comes Online

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

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

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

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

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

Why a Mid-infrared Observatory?

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

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

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

TAO Specs

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

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

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

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

For More Information

The TAO Project
World’s Highest Observatory Explores the Universe

The post The Highest Observatory in the World Comes Online appeared first on Universe Today.



Is the JWST Now an Interplanetary Meteorologist?

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

An unending, blistering inferno driven by ceaseless supersonic winds.

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

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

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

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

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

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

Michael Roman, University of Leicester.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

via GIPHY

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

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

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

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



What Can AI Learn About the Universe?

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

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

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

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

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

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

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

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

The Sloan Digital Sky Survey telescope stands out against the breaktaking backdrop of the Sacramento Mountains. 234 stars out of the Sloan's catalogue of over 2.5 million stars are producing an unexplained pulsed signal. Image: SDSS, Fermilab Visual Media Services
The Sloan Digital Sky Survey telescope stands out against the breathtaking backdrop of the Sacramento Mountains. Credit: SDSS/Fermilab Visual Media Services

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

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

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

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

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

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

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

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

Further Reading: arXiv

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



Wednesday, May 1, 2024

Enceladus’s Fault Lines are Responsible for its Plumes

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

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

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

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

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

Geysers erupt from Enceladus’ Tiger Stripes in this image from the Cassini spacecraft. Image Credit: By NASA/JPL/SSI – https://ift.tt/Tp9aVYK, Public Domain, https://ift.tt/VHZkPts

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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This is an Actual Picture of Space Debris

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

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

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

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

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

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

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

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

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