Space And The Universe News

  • If Europa has Geysers, They’re Very Faint
    by Evan Gough on April 10, 2024 at 1:20 am

    In 2013, the Hubble Space Telescope spotted water vapour on Jupiter’s moon Europa. The vapour was evidence of plumes similar to the ones on Saturn’s moon Enceladus. That, and other compelling evidence, showed that the moon has an ocean. That led to speculation that the ocean could harbour life.

    But the ocean is obscured under a thick, global layer of ice, making the plumes our only way of examining the ocean. The plumes are so difficult to detect they haven’t been confirmed.

    The lead author of the paper presenting Hubble’s 2013 evidence is Lorenz Roth of Southwest Research Institute. He said, “By far, the simplest explanation for this water vapour is that it erupted from plumes on the surface of Europa. If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice. And that is tremendously exciting.”

    It is, but first, scientists have to find the plumes.

    “We pushed Hubble to its limits to see this very faint emission. These could be stealth plumes because they might be tenuous and difficult to observe in visible light,” said Joachim Saur of the University of Cologne, co-author of the 2013 paper.

    This artist's illustration shows plumes erupting through Europa's icy surface. Gigantic Jupiter lurks in the background. Image Credit: NASA/ESA/K. Retherford/SWRI
    This artist’s illustration shows plumes erupting through Europa’s icy surface. Gigantic Jupiter lurks in the background. Image Credit: NASA/ESA/K. Retherford/SWRI

    Describing them as tenuous stealth plumes turned out to be prophetic.

    Recently, a team of researchers went looking for the plumes. Their results are in a presentation given to the IAU Symposium 383 titled “ALMA Spectroscopy of Europa: A Search for Active Plumes.” The lead author is M.A. Cordiner from the Solar System Exploration Division at NASA’s Goddard Space Flight Center.

    “The subsurface ocean of Europa is a high-priority target in the search for extraterrestrial life, but direct investigations are hindered by the presence of a thick exterior ice shell,” the authors write. The researchers used ALMA to search for molecular emissions from atmospheric plumes. They were investigating processes under the ice that could help them understand Europa’s ocean and its chemistry.

    The Solar System is full of icy bodies, including comets, Kuiper Belt Objects, dwarf planets, and moons like Europa. Europa has a high density compared to other icy bodies, indicating a substantial rocky interior. Its ocean makes up about 10% of the moon and is covered by an icy shell of uncertain thickness. It could be several tens of kilometres thick. Scientists learned much of this from NASA’s Galileo mission.

    In recent years, Europa and its ocean have leapt to the top of the list of targets in the search for life. The reasons aren’t obscure: liquid water is an irresistible beacon in our search for habitable places. The plumes from Europa’s ocean are our only way to study the ocean and its potential habitability.

    This illustration shows what the interior of Europa might look like. Geysers might erupt through cracks and fissures in the ice. Image Credit: NASA/JPL-Caltech/Michael Carroll)
    This illustration shows what the interior of Europa might look like. Geysers might erupt through cracks and fissures in the ice. Image Credit: NASA/JPL-Caltech/Michael Carroll)

    Over the years, different telescopes have examined Europa, searching for more evidence of the plumes. They’ve found potential intermittent plume activity near the moon’s south pole. But confirmation of the plumes the Hubble spotted in 2013 is elusive. In 2023, the JWST examined Europa. Those observations “found no evidence for active plumes, indicating that any present-day activity must be localized and weak; robust confirmation of the initial HST plume results also remains challenging,” the authors write.

    In an attempt to find the plumes, the authors employed ALMA, the Atacama Large Millimeter/submillimeter Array. They observed Europa on four separate days to cover the moon’s surface. Unfortunately, they found no plumes.

    These are four ALMA images of Europa. The researchers observed the moon on four different days so they could image almost the entire surface. They found no plumes. Image Credit: Cordiner et al. 2024.
    These are four ALMA images of Europa. The researchers observed the moon on four different days so they could image almost the entire surface. They found no plumes. Image Credit: Cordiner et al. 2024.

    “Despite near-complete coverage of both Europa’s leading and trailing hemispheres, we find no evidence for gas phase molecular absorption or emission in our ALMA data,” the researchers write. “Using ALMA’s unique combination of high spectral/spatial resolution and sensitivity, our observations have enabled the first dedicated search for HCN, H2CO, SO2 and CH3OH in Europa’s exosphere and plumes. No evidence was found for the presence of these molecules.”

    Finding no evidence doesn’t quite mean that those molecules aren’t there. Rather, it means that if they are there, their concentrations are so low they’re below the detection threshold. In this case, some concentrations would be lower than those detected in Enceladus’ plumes, which are confirmed.

    One chemical in particular illustrates this point: CH3OH (methanol.) “For the CH3OH abundance, on the
    other hand, our ALMA upper limit of < 0.86% would not have been sensitive enough to detect this molecule at the Enceladus plume abundance of 0.02%,” the authors write.

    There are some interesting relationships between Europa and other icy objects in the Solar System. It has to do with abundance limits. The researchers established upper limits for H2CO (formaldehyde) on Europa. “Indeed, our H2CO abundance upper limit is significantly lower than measured by Cassini in the Enceladus plume, implying a possible chemical difference.”

    Despite the fact that it didn’t find any plumes, the observations were still valuable. By setting detection limits it helps subsequent efforts to search for them. And this won’t be scientists’ final attempt at finding plumes. Anything that provides clues to Europa’s ocean is too tantalizing to ignore, and this research shows that ALMA is suited to this type of investigation.

    “Our results show that ALMA is a powerful tool in the search for outgassing from icy bodies within the Solar System and that follow-up searches for other molecules at additional epochs (on Europa and other icy bodies) are justified,” the researchers conclude.

    The post If Europa has Geysers, They’re Very Faint appeared first on Universe Today.

  • WISPR Team Images Turbulence within Solar Transients for the First Time
    by Mark Thompson on April 9, 2024 at 9:37 pm

    NASA’s Parker Solar Probe has been in studying the Sun for the last six years. In 2021 it was hit directly by a coronal mass ejection when it was a mere 10 million kilometres from the solar surface. Luckily it was gathering data and images enabling scientists to piece together an amazing video. The interactions between the solar wind and the coronal mass ejection were measured giving an unprecedented view of the solar corona. 

    The Sun is a fascinating object and as our local star, has been the subject of many studies. There are still mysteries though and it was hoping to unravel some of these that the NASA Parker Solar Probe was launched. It was sent on its way by the Delta IV heavy back in 2018 and has flown seven times closer to the Sun than any spacecraft before it. 

    Illustration of the Parker Solar Probe spacecraft approaching the Sun. Credits: Johns Hopkins University Applied Physics Laboratory

    By the time Parker completes its seven year mission it will have completed 24 orbits of the Sun and flown to within 6.2 million kilometres to the visible surface. For this to happen, its going to get very hot so the probe has a 11.4cm thick carbon composite shield to keep its components as cool as possible in the searing 1,377 Celsius temperatures. 

    Flying within the Sun’s outer atmosphere, the corona, the probe picked up turbulence inside a coronal mass ejection as it interacted with the solar wind. These events are eruptions of large amounts of highly magnetised and energetic plasma from within the Sun’s corona. When directed toward Earth they can cause magnetic and radio disruptions in many ways from communications to power systems. 

    Image of a coronal mass ejection being discharged from the Sun. (Credit: NASA/Goddard Space Flight Center/Solar Dynamics Observatory)

    Using the Wide Field Imager for Parker Solar Probe (WISPR) and its prime position inside the solar atmosphere, unprecedented footage was captured (click on this link for the video). The science team from the US Naval Research Laboratory revealed what seemed like turbulent eddies, so called Kelvin-Helmholtz instabilities (KHIs) in one of the images. Turbulent eddy structures like these have been seen in the atmosphere of terrestrial planets. Strong wind shear between upper and lower cloud levels causes thin trains of crescent wave like clouds. 

    Member of the WISPR team Evangelos Paouris PhD was the eagle eyed individual that spotted the disturbance. Paouris and team analysed the structure to verify the waves. The discovery of these rare features in the CME have opened up a whole new field of investigations.  

    The KHIs are the result of turbulence which plays a key role in the movement of CMEs as they flow through the ambient solar wind. Understanding the CMEs and their dynamics of CMEs and a more fuller understanding of the Sun’s corona. This doesn’t just help us understand the Sun but also helps to understand the effect of CMEs on Earth and our space based technology.

    Source : WISPR Team Images Turbulence within Solar Transients for the First Time

    The post WISPR Team Images Turbulence within Solar Transients for the First Time appeared first on Universe Today.

  • What Happens to Solar Systems When Stars Become White Dwarfs?
    by Evan Gough on April 9, 2024 at 9:35 pm

    In a couple billion years, our Sun will be unrecognizable. It will swell up and become a red giant, then shrink again and become a white dwarf. The inner planets aren’t expected to survive all the mayhem these transitions unleash, but what will happen to them? What will happen to the outer planets?

    Right now, our Sun is about 4.6 billion years old. It’s firmly in the main sequence now, meaning it’s going about its business fusing hydrogen into helium and releasing energy. But even though it’s about 330,000 times more massive than the Earth, and nearly all of that mass is hydrogen fuel, it will eventually run out.

    In another five billion years or so, its vast reservoir of hydrogen will suffer depletion. As it burns through its hydrogen, the Sun will lose mass. As it loses mass, its gravity weakens and can no longer counteract the outward force driven by fusion. A star is a balancing act between the outward expansion of fusion and the inward force of gravity. Eventually, the Sun’s billions-of-years-long balancing act will totter.

    With weakened gravity, the Sun will begin to expand and become a red giant.

    This illustration shows the current-day Sun at about 4.6 billion years old. In the future, the Sun will expand and become a red giant. Image Credit: By Oona Räisänen (User:Mysid), User:Mrsanitazier. - Vectorized in Inkscape by Mysid on a JPEG by Mrsanitazier (en:Image: Sun Red Giant2.jpg). CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2585107
    This illustration shows the current-day Sun at about 4.6 billion years old. In the future, the Sun will expand and become a red giant. Image Credit: By Oona Räisänen (User:Mysid), User:Mrsanitazier. – Vectorized in Inkscape by Mysid on a JPEG by Mrsanitazier (en:Image: Sun Red Giant2.jpg). CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2585107

    The Sun will almost certainly consume Mercury and Venus when it becomes a red giant. It will expand and become about 256 times larger than it is now. The inner two planets are too close, and there’s no way they can escape the swelling star. Earth’s fate is less certain. It may be swallowed by the giant Sun, or it may not. But even if it isn’t consumed, it will lose its oceans and atmosphere and become uninhabitable.

    The Sun will be a red giant for about one billion years. After that, it will undergo a series of more rapid changes, shrinking and expanding again. But the mayhem doesn’t end there.

    The Sun will pulse and shed its outer layers before being reduced to a tiny remnant of what it once was: a white dwarf.

    An artist's impression of a white dwarf star. The material inside white dwarfs is tightly packed, making them extremely dense. Image credit: Mark Garlick / University of Warwick.
    An artist’s impression of a white dwarf star. The material inside white dwarfs is tightly packed, making them extremely dense. Image credit: Mark Garlick / University of Warwick.

    This will happen to the Sun, its ilk, and almost all stars that host planets. Even the long-lived red dwarfs (M-dwarfs) will eventually become white dwarfs, though their path is different.

    Astronomers know the fate of planets too close to the stars undergoing these tumultuous changes. But what happens to planets further away? To their moons? To asteroids and comets?

    New research published in The Monthly Notices of the Royal Astronomical Society digs into the issue. The title is “Long-term variability in debris transiting white dwarfs,” and the lead author is Dr. Amornrat Aungwerojwit of Naresuan University in Thailand.

    “Practically all known planet hosts will evolve eventually into white dwarfs, and large parts of the various components of their planetary systems—planets, moons, asteroids, and comets—will survive that metamorphosis,” the authors write.

    There’s lots of observational evidence for this. Astronomers have detected planetary debris polluting the photospheres of white dwarfs, and they’ve also found compact debris disks around white dwarfs. Those findings show that not everything survives the main sequence to red giant to white dwarf transition.

    “Previous research had shown that when asteroids, moons and planets get close to white dwarfs, the huge gravity of these stars rips these small planetary bodies into smaller and smaller pieces,” said lead author Aungwerojwit.

    This Hubble Space Telescope shows Sirius, with its white dwarf companion Sirius B to the lower left. Sirius B is the closest white dwarf to the Sun. Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester).
    This Hubble Space Telescope shows Sirius, with its white dwarf companion Sirius B to the lower left. Sirius B is the closest white dwarf to the Sun. Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester).

    In this research, the authors observed three white dwarfs over the span of 17 years. They analyzed the changes in brightness that occurred. Each of the three stars behaved differently.

    When planets orbit stars, their transits are orderly and predictable. Not so with debris. The fact that the three white dwarfs showed such disorderly transits means they’re being orbited by debris. It also means the nature of that debris is changing.

    “The unpredictable nature of these transits can drive astronomers crazy—one minute they are there, the next they are gone.”

    Professor Boris Gaensicke, University of Warwick

    As small bodies like asteroids and moons are torn into small pieces, they collide with one another until nothing’s left but dust. The dust forms clouds and disks that orbit and rotate around the white dwarfs.

    Professor Boris Gaensicke of the University of Warwick is one of the study’s co-authors. “The simple fact that we can detect the debris of asteroids, maybe moons or even planets whizzing around a white dwarf every couple of hours is quite mind-blowing, but our study shows that the behaviour of these systems can evolve rapidly, in a matter of a few years,” Gaensicke said.

    “While we think we are on the right path in our studies, the fate of these systems is far more complex than we could have ever imagined,” added Gaensicke.

    This artist's illustration shows the white dwarf WD J0914+1914 (Not part of this research.) A Neptune-sized planet orbits the white dwarf, and the white dwarf is drawing material away from the planet and forming a debris disk around the star. Image Credit: By ESO/M. Kornmesser - https://www.eso.org/public/images/eso1919a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=84618722
    This artist’s illustration shows the white dwarf WD J0914+1914 (Not part of this research.) A Neptune-sized planet orbits the white dwarf, and the white dwarf is drawing material away from the planet and forming a debris disk around the star. Image Credit: By ESO/M. Kornmesser – https://www.eso.org/public/images/eso1919a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=84618722

    During the 17 years of observations, all three white dwarfs showed variability.

    The first white dwarf (ZTF J0328?1219) was steady and stable until a major catastrophic event around 2011. “This might suggest that the system underwent a large collisional event around 2011, resulting in the production of large amounts of dust occulting the white dwarf, which has since then gradually dispersed, though leaving sufficient material to account for the ongoing transit activity, which implies continued dust production,” the researchers explain.

    The second white dwarf (ZTF J0923+4236) dimmed irregularly every couple of months and displayed chaotic variability on the timescale of minutes. “These long-term changes may be the result of the ongoing disruption of a planetesimal or the collision between multiple fragments, both leading to a temporarily increased dust production,” the authors explain in their paper.

    The third star (WD 1145+017) showed large variations in numbers, shapes and depths of transits in 2015. This activity “concurs with a large increase in transit activity, followed by a subsequent gradual re-brightening,” the authors explain, adding that “the overall trends seen in the brightness of WD?1145+017 are linked to varying amounts of transit activity.”

    But now all those transits are gone.

    “The unpredictable nature of these transits can drive astronomers crazy—one minute they are there, the next they are gone,” said Gaensicke. “And this points to the chaotic environment they are in.”

    But astronomers have also found planetesimals, planets, and giant planets around white dwarfs, indicating that the stars’ transitions from main sequence to red giant don’t destroy everything. The dust and debris that astronomers see around these white dwarfs might come from asteroids or from moons pulled free from their giant planets.

    “For the rest of the Solar System, some of the asteroids located between Mars and Jupiter, and maybe some of the moons of Jupiter may get dislodged and travel close enough to the eventual white dwarf to undergo the shredding process we have investigated,” said Professor Gaensicke.

    When our Sun finally becomes a white dwarf, it will likely have debris around it. But the debris won’t be from Earth. One way or another, the Sun will destroy Earth during its red giant phase.

    “Whether or not the Earth can just move out fast enough before the Sun can catch up and burn it is not clear, but [if it does] the Earth would [still] lose its atmosphere and ocean and not be a very nice place to live,” explained Professor Gaensicke.

    The post What Happens to Solar Systems When Stars Become White Dwarfs? appeared first on Universe Today.

  • A Neutron Star Merged with a Surprisingly Light Black Hole
    by Mark Thompson on April 9, 2024 at 7:36 pm

    Galactic collisions, meteor impacts and even stellar mergers are not uncommon events. neutron stars colliding with black holes however are a little more rare, in fact, until now, we have never observed one. The fourth LIGO-Virgo-KAGRA observing detected gravitational waves from a collision between a black hole and neutron star 650 million light years away. The black hole was tiny though with a mass between 2.5 to 4.5 times that of the Sun. 

    Neutron stars and black holes have something in common; they are both the remains of a massive star that has reached the end of its life. During the main part of a stars life the inward pull of gravity is balanced by the outward push of the thermonuclear pressure that makes the star shine. The thermonuclear pressure overcomes gravity for low mass stars like the Sun but for more massive stars, gravity wins. The core collapses compressing it into either a neutron star or a black hole (depending on the progenitor star mass) and explodes as a supernova – in the blink of an eye. 

    In May 2023, as a result of the fourth observing session of the LIGO-Virgo-KAGRA (Laser Interferometer Gravitational Wave Observatory-Virgo Gravitational Wave Interferometer and Kamioka Gravitational Wave Detector) network, gravitational waves were picked up from a merger event. The signal came from an object 1.2 times the mass of the Sun and another slightly more massive object. Further analysis revealed the likelihood that one was a neutron star and the other a low mass black hole. The latter falls into the so called ‘mass gap’, more massive than the most massive neutron star and less massive than the least massive black hole.

    Interactions between objects can generate gravitational waves. Before they were detected back in 2015, stellar mass black holes were typically found through X-ray observations. Neutron stars on the other hand, were usually found with radio observations. Between the two, was the mass gap with objects lacking between three and five solar masses. 

    It has been the subject of debate among scientists with the odd object found which fell within the gap, fuelling debate about its existence. The gap has generally been considered to separate the neutron stars from the black holes and items in this mass group have been scarce. This gravitational wave discovery suggests maybe objects in this gap are not so rare after-all. 

    One of the challenges of detecting mass gap objects and mergers between them is the sensitivity of detectors. The LIGO team at the University of British Columbia researchers are working hard to improve the coatings used in mirror production. Enhanced performance on future LIGO detectors will further enhance detection capabilities. It’s not just optical equipment that is being developed, infrastructure changes are also being addressed including data analysis software too. Improving sensitivity in all aspects of the gravity wave network is sure to yield results in future runs. However for now, the rest of the first half of the observing run needs analysing with 80 more candidate signals to study. 

    Source : New gravitational wave signal helps fill the ‘mass gap’ between neutron stars and black holes

    The post A Neutron Star Merged with a Surprisingly Light Black Hole appeared first on Universe Today.

  • The Seven Most Intriguing Worlds to Search for Advanced Civilizations (So Far)
    by Andy Tomaswick on April 9, 2024 at 6:29 pm

    Sometimes, the easy calculations are the most interesting. A recent paper from Balázs Bradák of Kobe University in Japan is a case in point. In it, he takes an admittedly simplistic approach but comes up with seven known exoplanets that could hold the key to the biggest question of them all – are we alone?

    Dr. Bradák starts with a simple premise – there is a chance that life on Earth might have started via panspermia. There is also a case that panspermia was intention – an advanced civilization could theoretically have purposefully sent a biological seed ship to our local solar system to spread life here, essentially from scratch.

    With those admittedly very large assumptions in place, Dr. Bradák works out a few characteristics about the planets that could have been the starting point for such a civilization. First, he assumes, as much of the astrobiological community does, that for an advanced civilization to arise on a planet, that planet has to be at least partially covered in an ocean. 

    Sun-like stars aren’t the only potential hosts for habitable planets, as Fraser discusses here.

    To meet that requirement, the planet has to be both the right size and the right temperature. The two size categories of exoplanets that Dr. Bradák originally selected were “terrestrial” – planets similar to Earth, including so-called “Super-Earths” – and “sub-Neptunes” – planets that are significantly larger than Earth but smaller than the ice giant in the outer fringes of our solar system.

    Any such exoplanet also has to be in the habitable zone of its parent star. That alone dramatically narrows the potential field of planetary candidates. For simplicity’s sake, Dr. Bradák also eliminates sub-Neptunes as a potential planetary class. However, one other factor comes into play as well: age.

    We know it took around 4.6 billion years for life to evolve to a point where it could theoretically send objects to other star systems – as we have now with Voyager. Since the original planet would also have to have evolved such a civilization, it would be double the time for its minimum age – or 9.2 billion years old.

    The idea of panspermia has been around for decades, as Fraser discusses.

    Dr. Bradák adds some additional argument that lowers the required age of the system – and he also assumes that the planetary system of a star forms at a similar time gap as our planetary system did. The distance to most of these stars is inconsequential on the scale of billions of years, so the travel time for the seed ship was discounted in this calculation. 

    After all that pruning, Dr. Bradák turned to NASA’s Exoplanet Archive, which currently contains 5271 known exoplanets. Of those 5271, only 7 meet the specified age, size, and habitable zone placement criteria. In other words, according to our current knowledge of exoplanets and how life evolved, only a few planets could potentially have been the starting point for an intentional panspermia campaign.

    One planet in particular stands out – Kepler-452 b, which has a star similar to ours and an orbit similar to ours. That system is only 1,400 light years away, relatively close by astronomical standards. If nothing else, it points to that system as a potentially interesting focal point for exoplanet surveys, including assessments of exoplanet atmospheres. However, we’ll likely have to wait for the next generation of grand telescopes.

    For now, this was an interesting, though brief, speculative exercise. Astronomers are always looking for exciting things, and this paper contributes to the arguments about why it’s so important to spend time looking in detail at some of the exoplanets we already know about.

    Learn More:
    B. Bradák – A BOLD AND HASTY SPECULATION ABOUT ADVANCED CIVILIZATION-BEARING PLANETS
    APPEARING IN EXOPLANET DATABASES

    UT – A Super-Earth (and Possible Earth-Sized) Exoplanet Found in the Habitable Zone
    UT – A New Place to Search for Habitable Planets: “The Soot Line.”
    UT – Want to Find Life? Compare a Planet to its Neighbors

    Lead Image:
    Artist’s illustration of a habitable planet.
    Credit – Wikipedia / VP8/Vorbis

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  • What a Swarm of Probes Can Teach Us About Proxima Centauri B
    by Evan Gough on April 9, 2024 at 5:06 pm

    You’ve likely heard of the Breakthrough Starshot (BTS) initiative. BTS aims to send tiny gram-scale, light sail picospacecraft to our neighbour, Proxima Centauri B. In BTS’s scheme, lasers would propel a whole fleet of tiny probes to the potentially water-rich exoplanet.

    Now, another company, Space Initiatives Inc., is tackling the idea. NASA has funded them so they can study the idea. What can we expect to learn from the effort?

    Proxima b may be a close neighbour in planetary terms. But it’s in a completely different solar system, about four light-years away. That means any probes sent there must travel at relativistic speeds if we want them to arrive in a reasonable amount of time.

    That’s why Space Initiatives Inc. proposes such tiny spacecraft. With their small masses, direct lasers can propel them to their destination. That means they must send a swarm of hundreds or even one thousand probes to get valuable scientific results.

    This is much different than the architecture that missions usually conform to. Most missions are a single spacecraft, perhaps with a smaller attached probe like the Huygens probe attached to the Cassini spacecraft. How does using a swarm change the mission? What results can we expect?

    “We anticipate our innovations would have a profound effect on space exploration.”

    Thomas Eubanks, Space Inititatives Inc.

    A new presentation at the 55th Lunar and Planetary Science Conference (LPSC) in Texas examined the idea. It’s titled “SCIENTIFIC RETURN FROM IN SITU EXPLORATION OF THE PROXIMA B EXOPLANET.” The lead author is T. Marshall Eubanks from Space Initiatives Inc., a start-up developing 50-gram femtosatellites that weigh less than 100 grams (3.5 oz.)

    Tiny probes like these can only do flybys. They’re too tiny and low-mass for anything else. When designing a mission like this, the first consideration is whether the probes will operate as a dispersed or coherent swarm. In a dispersed swarm, the probes reach their destination sequentially. In a coherent swarm, the probes are together when they do their flyby. Both architectures have their merits.

    In either case, these tiny solar sail probes will be very thin. But thanks to technological advances, they can still gather high-resolution images by working together.

    The image below shows 247 probes forming an array as they fly by Proxima b. Together, they have the light-collecting area of a three-meter telescope. This arrangement should enable sub-arc-second resolutions at optical wavelengths. Spectroscopy should be equally as fine.

    “While both erosion by the Interstellar Medium (ISM) and image smearing will degrade imaging, we anticipate these systems will enable sub-arcsecond resolution imaging and spectroscopy of the target planet,” the authors write.

    This image from the presentation shows how the probe swarm would arrive at Proxima b. (Note that the planned swarm dispersion is much smaller than is indicated here.) Image Credit: Eubanks et al. 2024.
    This image from the presentation shows how the probe swarm would arrive at Proxima b. (Note that the planned swarm dispersion is much smaller than is indicated here.) Image Credit: Eubanks et al. 2024.

    These tiny spacecraft could do some course correction, but not much. So, getting the navigation right is critical. Unfortunately, our data on Proxima b’s orbit is not as well-understood as the planets in our own Solar System. It all comes down to ephemeris.

    Ephemeris tables show the trajectory of planets and other objects in space. But in Proxima b’s case, the ephemeris error is potentially quite large.

    Added to that is the distance. If the probes can travel at 20% of light speed, reaching the planet will take over 21 years. The authors calculate that if they can restrict Proxima b’s ephemeris error to 100,000 km and send 1,000 probes, at least one will come within 1,000 km of the planet. “Meeting this ephemeris error goal will require improved astrometry of the Proxima system,” the authors write.

    The probes would perform science observations on their way to Proxima b. As they travel, the swarm would have dozens or even hundreds of opportunities to use microlensing to study stellar objects. A stellar mass microlensing event requiring one month on Earth would only take one hour.

    “It is now possible to predict lensing events for nearby stars; BTS probe observations of dozens or hundreds of predicted microlensing events by nearby stars will offer both a means of observing these systems and a novel means of interstellar navigation,” the authors explain.

    The swarm would be only the third mission to leave our Solar System. The Voyage spacecraft left the heliosphere, but only inadvertently. So, the swarm could observe the interstellar medium (ISM) during its 20+ year journey. One of the questions we have about the local ISM concerns clouds. We only have poor data on the nature of these clouds, and scientists aren’t certain if our Solar System is in the Local Interstellar Cloud (LIC.)

    “In situ observation of the properties of these clouds will be a primary scientific goal for mission science during the long interstellar voyage,” the researchers write.

    There are clouds in the ISM near our Solar System. But we don't know much about them, including if our Solar System is in the LIC or if it's leaving it. Image Credit: Interstellar Probe/JHUAPL
    There are clouds in the ISM near our Solar System. But we don’t know much about them, including if our Solar System is in the LIC or if it’s leaving it. Image Credit: Interstellar Probe/JHUAPL

    Opportunistic science during the voyage is great, but arrival at Proxima b is the meat of the mission. One day before the probes arrive, they would still be 35 AU away. At that point, the mission could begin imaging. Proxima b would still only be several pixels across, but it’s enough to see any visible moons.

    “At this point, it would be worth turning some probes to face forward and begin imaging the Proxima system to search for undiscovered planets, moons and asteroids in the system, and to begin a Proxima b approach video,” the researchers explain.

    Upon arrival at Proxima Centauri b, a one-meter aperture telescope 6,000 km away from the planet could attain a six-meter resolution on the surface. That’s an idealistic number, as not all of the planet’s surface could be imaged at that resolution. PCb is also tidally locked to its star, meaning one side is in darkness. Because of that, the mission should be designed to gather low-light and infrared images of the night side. “Night-side illumination imagery might also be the most conclusive technosignature from an initial Proxima mission,” the authors write.

    As probes pass through Proxima b’s shadow, they could use the light from the star to perform spectroscopy. Probes passing behind Proxima b could use the Earth laser system for spectrometry, and if the probes are in a coherent swarm, they could use the lasers from pairs of probes on either side of the planet.

    “Transmission spectroscopy, which for Proxima b cannot be done from Earth,” the researchers explain, “will likely provide the best means of determining the existence of a biology or even a technological society on Proxima b through the search for the spectral lines of biomarkers and technomarkers.”

    As humanity’s first mission to Proxima Centauri b, the swarm would face some hurdles and uncertainties. But in a coherent swarm architecture, the mission could also be almost too successful. “A BTS mission, especially with a coherent swarm, may collect more data than can be returned to Earth,” the authors write. If the data returned has to be selected autonomously by the swarm itself, that could be more demanding than deciding what data to collect in the first place.

    Scientists have many questions about Proxima Centauri b. Should the swarm ever be launched, any amount of data it returns will be valuable. Even though it’ll take over four years for the data to be sent back to Earth.

    An artist's conception of a violent flare erupting from the red dwarf star Proxima Centauri. Such flares can obliterate the atmospheres of nearby planets. Credit: NRAO/S. Dagnello.
    An artist’s conception of a violent flare erupting from the red dwarf star Proxima Centauri. Such flares can obliterate the atmospheres of nearby planets. Credit: NRAO/S. Dagnello.

    Scientists don’t know how hot the planet is. They’re not certain if it even has liquid water. It looks like the planet is just over one Earth mass and has a slightly higher radius. But those measurements are uncertain. Scientists are also uncertain about its composition. The star it orbits is a flare star, which means the planet could be subjected to extremely powerful bursts of radiation. That’s a lot of uncertainty.

    But it’s the nearest exoplanet, the only one we could feasibly reach in a realistic amount of time. That alone makes it a desirable target.

    There’s no final plan for a mission like this. It’s largely conceptual. But the technology to do it is coming along. NASA has funded a mission study, so it definitely has merit.

    “Fortunately, we don’t have to wait until mid-century to make practical progress – we can explore and test swarming techniques now in a simulated environment, which is what we propose to do in this work,” said report lead author Thomas Eubanks from Space Initiatives Inc. “We anticipate our innovations would have a profound effect on space exploration, complementing existing techniques and enabling entirely new types of missions, for example, picospacecraft swarms covering all of cislunar space or instrumenting an entire planetary magnetosphere.”

    Eubanks also points out how a swarm of probes could investigate interstellar objects that pass through our inner Solar System, like Oumuamua.

    But the main mission would be the one to Proxima Centauri b. According to Eubanks, that would happen sometime in the third quarter of this century.

    The post What a Swarm of Probes Can Teach Us About Proxima Centauri B appeared first on Universe Today.

  • Measuring the Atmospheres of Other Worlds to See if There are Enough Nutrients for Life
    by Evan Gough on April 8, 2024 at 10:25 pm

    Life on Earth depends on six critical elements: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, and Sulfur. These elements are referred to as CHNOPS, and along with several trace micronutrients and liquid water, they’re what life needs.

    Scientists are getting a handle on detecting exoplanets that might be warm enough to have liquid water on their surfaces, habitability’s most basic signal. But now, they’re looking to up their game by finding CHNOPS in exoplanet atmospheres.

    We’re only at the beginning of understanding how exoplanets could support life. To grow our understanding, we need to understand the availability of CHNOPS in planetary atmospheres.

    A new paper examines the issue. It’s titled “Habitability constraints by nutrient availability in atmospheres of rocky exoplanets.” The lead author is Oliver Herbort from the Department of Astrophysics at the University of Vienna and an ARIEL post-doctoral fellow. The paper has been accepted by the International Journal of Astrobiology.

    At our current technological level, we’re just beginning to examine exoplanet atmospheres. The JWST is our main tool for the task, and it’s good at it. But the JWST is busy with other tasks. In 2029, the ESA will launch ARIEL, the Atmospheric Remote-sensing Infrared Exoplanet Large survey. ARIEL will be solely focused on exoplanet atmospheres.

    An artist's impression of the ESA's Ariel space telescope. During its four-year mission, it'll examine 1,000 exoplanet atmospheres with the transit method. It'll study and characterize both the compositions and thermal structures. Image Credit: ESA
    An artist’s impression of the ESA’s Ariel space telescope. During its four-year mission, it’ll examine 1,000 exoplanet atmospheres with the transit method. It’ll study and characterize both the compositions and thermal structures. Image Credit: ESA

    In anticipation of that telescope’s mission, Herbort and his co-researchers are preparing for the results and what they mean for habitability. “The detailed understanding of the planets itself becomes important for interpreting observations, especially for the detection of biosignatures,” they write. In particular, they’re scrutinizing the idea of aerial biospheres. “We aim to understand the presence of these nutrients within atmospheres that show the presence of water cloud condensates, potentially allowing the existence of aerial biospheres.”

    Our sister planet Venus has an unsurvivable surface. The extreme heat and pressure make the planet’s surface uninhabitable by any measure we can determine. But some scientists have proposed that life could exist in Venus’ atmosphere, based largely on the detection of phosphine, a possible indicator of life. This is an example of what an aerial biosphere might look like.

    This artistic impression depicts Venus. Astronomers at MIT, Cardiff University, and elsewhere may have observed signs of life in the atmosphere of Venus by detecting phosphine. Subsequent research disagreed with this finding, but the issue is ongoing. Image Credits: ESO (European Space Organization)/M. Kornmesser & NASA/JPL/Caltech
    This artistic impression depicts Venus. Astronomers at MIT, Cardiff University, and elsewhere may have observed signs of life in the atmosphere of Venus by detecting phosphine. Subsequent research disagreed with this finding, but the issue is ongoing. Image Credits: ESO (European Space Organization)/M. Kornmesser & NASA/JPL/Caltech

    “This concept of aerial biospheres enlarges the possibilities of potential habitability from the presence of liquid water on the surface to all planets with liquid water clouds,” the authors explain.

    The authors examined the idea of aerial biospheres and how the detection of CHNOPS plays into them. They introduced the concept of nutrient availability levels in exoplanet atmospheres. In their framework, the presence of water is required regardless of other nutrient availability. “We considered any atmosphere without water condensates as uninhabitable,” they write, a nod to water’s primacy. The researchers assigned different levels of habitability based on the presence and amounts of the CHNOPS nutrients.

    This table from the research illustrates the authors' concept of atmospheric nutrient availability. As the top row shows, without water, no atmosphere is habitable. Different combinations of nutrients have different habitability potential. 'red' stands for redox, and 'ox' stands for the presence of the oxidized state of CO2, NOx, and SO2. Image Credit: Herbort et al. 2024.
    This table from the research illustrates the authors’ concept of atmospheric nutrient availability. As the top row shows, without water, no atmosphere is habitable. Different combinations of nutrients have different habitability potential. ‘red’ stands for redox, and ‘ox’ stands for the presence of the oxidized state of CO2, NOx, and SO2. Image Credit: Herbort et al. 2024.

    To explore their framework of nutrient availability, the researchers turned to simulations. The simulated atmospheres held different levels of nutrients, and the researchers applied their concept of nutrient availability. Their results aim to understand not habitability but the chemical potential for habitability. A planet’s atmosphere can be altered drastically by life, and this research aims to understand the atmospheric potential for life.

    “Our approach does not directly aim for the understanding of biosignatures and atmospheres of planets, which are inhabited, but for the conditions in which pre-biotic chemistry can occur,” they write. In their work, the minimum atmospheric concentration for a nutrient to be available is 10?9, or one ppb (part per billion.)

    “We find that for most atmospheres at ( p gas, T gas) points, where liquid water is stable, CNS-bearing molecules are present at concentrations above 10?9,” they write. They also found that carbon is generally present in every simulated atmosphere and that sulphur availability increases with surface temperature. With lower surface temperatures, nitrogen (N2, NH3) is present in increasing amounts. But with higher surface temperatures, nitrogen can become depleted.

    Phosphorus is a different matter. “The limiting element of the CHNOPS elements is phosphorus, which is mostly bound in the planetary crust,” they write. The authors point out that, at past times in Earth’s atmosphere, phosphorus scarcity limited the biosphere.

    An aerial biosphere is an interesting idea. But it’s not the main thrust of scientists’ efforts to detect exoplanet atmospheres. Surface life is their holy grail. It should be no surprise that it still comes down to liquid water, all things considered. “Similar to previous work, our models suggest that the limiting factor for habitability at the surface of a planet is the presence of liquid water,” the authors write. In their work, when surface water was available, CNS was available in the lower atmosphere near the surface.

    But surface water plays several roles in atmospheric chemistry. It can bond with some nutrients in some circumstances, making them unavailable, and in other circumstances, it can make them available.

    “If water is available at the surface, the elements not present in the gas phase are stored in the crust condensates,” the authors write. Chemical weathering can then make them available as nutrients. “This provides a pathway to overcome the lack of atmospheric phosphorus and metals, which are used in enzymes that drive many biological processes.”

    Artist's impression of the surface of a hycean world. Hycean worlds are still hypothetical, with large oceans and thick hydrogen-rich atmospheres that trap heat. It's unclear if a world with no surface can support life. Image Credit: University of Cambridge
    Artist’s impression of the surface of a hycean world. Hycean worlds are still hypothetical, with large oceans and thick hydrogen-rich atmospheres that trap heat. It’s unclear if a world with no surface can support life. Image Credit: University of Cambridge

    This complicates matters on worlds covered by oceans. Pre-biotic molecules might not be available if there’s no opportunity for water and rock to interact with the atmosphere. “If indeed it can be shown that life can form in a water ocean without any exposed land, this constraint becomes weaker, and the potential for the surface habitability becomes mainly a question of water stability,” the authors write.

    Some of the models are surprising because of atmospheric liquid water. “Many of the models show the presence of a liquid water zone in the atmospheres, which is detached from the surface. These regions could be of interest for the formation of life in forms of aerial biospheres,” Herbort and his colleagues write.

    If there’s one thing that research like this shows, planetary atmospheres are extraordinarily complex and can change dramatically over time, sometimes because of life itself. This research makes some sense in trying to understand it all. Emphasizing the complexity is the fact that the researchers didn’t include stellar radiation in their work. Including that would’ve made the effort unwieldy.

    The habitability issue is complicated, confounded by our lack of answers to foundational questions. Does a planet’s crust have to be in contact with water and the atmosphere for the CHNOPS nutrients to be available? Earth has a temporary aerial biosphere. Can aerial biospheres be an important part of exoplanet habitability?

    But beyond all the simulations and models, as powerful as they are, what scientists need most is more data. When ARIEL launches, scientists will have much more data to work with. Research like this will help scientists understand what ARIEL finds.

    The post Measuring the Atmospheres of Other Worlds to See if There are Enough Nutrients for Life appeared first on Universe Today.

  • Does the Rise of AI Explain the Great Silence in the Universe?
    by Evan Gough on April 8, 2024 at 7:18 pm

    Artificial Intelligence is making its presence felt in thousands of different ways. It helps scientists make sense of vast troves of data; it helps detect financial fraud; it drives our cars; it feeds us music suggestions; its chatbots drive us crazy. And it’s only getting started.

    Are we capable of understanding how quickly AI will continue to develop? And if the answer is no, does that constitute the Great Filter?

    The Fermi Paradox is the discrepancy between the apparent high likelihood of advanced civilizations existing and the total lack of evidence that they do exist. Many solutions have been proposed for why the discrepancy exists. One of the ideas is the “Great Filter.”

    The Great Filter is a hypothesized event or situation that prevents intelligent life from becoming interplanetary and interstellar and even leads to its demise. Think climate change, nuclear war, asteroid strikes, supernova explosions, plagues, or any number of other things from the rogue’s gallery of cataclysmic events.

    Or how about the rapid development of AI?

    A new paper in Acta Astronautica explores the idea that Artificial Intelligence becomes Artificial Super Intelligence (ASI) and that ASI is the Great Filter. The paper’s title is “Is Artificial Intelligence the Great Filter that makes advanced technical civilizations rare in the universe?” The author is Michael Garrett from the Department of Physics and Astronomy at the University of Manchester.

    “Without practical regulation, there is every reason to believe that AI could represent a major threat to the future course of not only our technical civilization but all technical civilizations.”

    Michael Garrett, University of Manchester

    Some think the Great Filter prevents technological species like ours from becoming multi-planetary. That’s bad because a species is at greater risk of extinction or stagnation with only one home. According to Garrett, a species is in a race against time without a backup planet. “It is proposed that such a filter emerges before these civilizations can develop a stable, multi-planetary existence, suggesting the typical longevity (L) of a technical civilization is less than 200 years,” Garrett writes.

    If true, that can explain why we detect no technosignatures or other evidence of ETIs (Extraterrestrial Intelligences.) What does that tell us about our own technological trajectory? If we face a 200-year constraint, and if it’s because of ASI, where does that leave us? Garrett underscores the “…critical need to quickly establish regulatory frameworks for AI development on Earth and the advancement of a multi-planetary society to mitigate against such existential threats.”

    An image of our beautiful Earth taken by the Galileo spacecraft in 1990. Do we need a backup home? Credit: NASA/JPL
    An image of our beautiful Earth taken by the Galileo spacecraft in 1990. Do we need a backup home? Credit: NASA/JPL

    Many scientists and other thinkers say we’re on the cusp of enormous transformation. AI is just beginning to transform how we do things; much of the transformation is behind the scenes. AI seems poised to eliminate jobs for millions, and when paired with robotics, the transformation seems almost unlimited. That’s a fairly obvious concern.

    But there are deeper, more systematic concerns. Who writes the algorithms? Will AI discriminate somehow? Almost certainly. Will competing algorithms undermine powerful democratic societies? Will open societies remain open? Will ASI start making decisions for us, and who will be accountable if it does?

    This is an expanding tree of branching questions with no clear terminus.

    Stephen Hawking (RIP) famously warned that AI could end humanity if it begins to evolve independently. “I fear that AI may replace humans altogether. If people design computer viruses, someone will design AI that improves and replicates itself. This will be a new form of life that outperforms humans,” he told Wired magazine in 2017. Once AI can outperform humans, it becomes ASI.

    Stephen Hawking was a major proponent for colonizing other worlds, mainly to ensure humanity does not go extinct. In later years, Hawking recognized that AI could be an extinction-level threat. Credit: educatinghumanity.com
    Stephen Hawking was a major proponent for colonizing other worlds, mainly to ensure humanity does not go extinct. In later years, Hawking recognized that AI could be an extinction-level threat. Credit: educatinghumanity.com

    Hawking may be one of the most recognizable voices to issue warnings about AI, but he’s far from the only one. The media is full of discussions and warnings, alongside articles about the work AI does for us. The most alarming warnings say that ASI could go rogue. Some people dismiss that as science fiction, but not Garrett.

    “Concerns about Artificial Superintelligence (ASI) eventually going rogue is considered a major issue – combatting this possibility over the next few years is a growing research pursuit for leaders in the field,” Garrett writes.

    If AI provided no benefits, the issue would be much easier. But it provides all kinds of benefits, from improved medical imaging and diagnosis to safer transportation systems. The trick for governments is to allow benefits to flourish while limiting damage. “This is especially the case in areas such as national security and defence, where responsible and ethical development should be paramount,” writes Garrett.

    News reports like this might seem impossibly naive in a few years or decades.

    The problem is that we and our governments are unprepared. There’s never been anything like AI, and no matter how we try to conceptualize it and understand its trajectory, we’re left wanting. And if we’re in this position, so would any other biological species that develops AI. The advent of AI and then ASI could be universal, making it a candidate for the Great Filter.

    This is the risk ASI poses in concrete terms: It could no longer need the biological life that created it. “Upon reaching a technological singularity, ASI systems will quickly surpass biological intelligence and evolve at a pace that completely outstrips traditional oversight mechanisms, leading to unforeseen and unintended consequences that are unlikely to be aligned with biological interests or ethics,” Garrett explains.

    How could ASI relieve itself of the pesky biological life that corrals it? It could engineer a deadly virus, it could inhibit agricultural food production and distribution, it could force a nuclear power plant to melt down, and it could start wars. We don’t really know because it’s all uncharted territory. Hundreds of years ago, cartographers would draw monsters on the unexplored regions of the world, and that’s kind of what we’re doing now.

    This is a portion of the Carta Marina map from the year 1539. It shows monsters lurking in the unknown waters off of Scandinavia. Are the fears of ASI kind of like this? Or could ASI be the Great Filter? Image Credit: By Olaus Magnus - http://www.npm.ac.uk/rsdas/projects/carta_marina/carta_marina_small.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=558827
    This is a portion of the Carta Marina map from the year 1539. It shows monsters lurking in the unknown waters off of Scandinavia. Are the fears of ASI kind of like this? Or could ASI be the Great Filter? Image Credit: By Olaus Magnus – http://www.npm.ac.uk/rsdas/projects/carta_marina/carta_marina_small.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=558827

    If this all sounds forlorn and unavoidable, Garrett says it’s not.

    His analysis so far is based on ASI and humans occupying the same space. But if we can attain multi-planetary status, the outlook changes. “For example, a multi-planetary biological species could take advantage of independent experiences on different planets, diversifying their survival strategies and possibly avoiding the single-point failure that a planetary-bound civilization faces,” Garrett writes.

    If we can distribute the risk across multiple planets around multiple stars, we can buffer ourselves against the worst possible outcomes of ASI. “This distributed model of existence increases the resilience of a biological civilization to AI-induced catastrophes by creating redundancy,” he writes.

    If one of the planets or outposts that future humans occupy fails to survive the ASI technological singularity, others may survive. And they would learn from it.

    Artist's illustration of a SpaceX Starship landing on Mars. If we can become a multi-planetary species, the threat of ASI is diminished. Credit: SpaceX
    Artist’s illustration of a SpaceX Starship landing on Mars. If we can become a multi-planetary species, the threat of ASI is diminished. Credit: SpaceX

    Multi-planetary status might even do more than just survive ASI. It could help us master it. Garrett imagines situations where we can experiment more thoroughly with AI while keeping it contained. Imagine AI on an isolated asteroid or dwarf planet, doing our bidding without access to the resources required to escape its prison. “It allows for isolated environments where the effects of advanced AI can be studied without the immediate risk of global annihilation,” Garrett writes.

    But here’s the conundrum. AI development is proceeding at an accelerating pace, while our attempts to become multi-planetary aren’t. “The disparity between the rapid advancement of AI and the slower progress in space technology is stark,” Garrett writes.

    The difference is that AI is computational and informational, but space travel contains multiple physical obstacles that we don’t yet know how to overcome. Our own biological nature restrains space travel, but no such obstacle restrains AI. “While AI can theoretically improve its own capabilities almost without physical constraints,” Garrett writes, “space travel must contend with energy limitations, material science boundaries, and the harsh realities of the space environment.”

    For now, AI operates within the constraints we set. But that may not always be the case. We don’t know when AI might become ASI or even if it can. But we can’t ignore the possibility. That leads to two intertwined conclusions.

    If Garrett is correct, humanity must work more diligently on space travel. It can seem far-fetched, but knowledgeable people know it’s true: Earth will not be inhabitable forever. Humanity will perish here by our own hand or nature’s hand if we don’t expand into space. Garrett’s 200-year estimate just puts an exclamation point on it. A renewed emphasis on reaching the Moon and Mars offers some hope.

    The Artemis program is a renewed effort to establish a presence on the Moon. After that, we could visit Mars. Are these our first steps to becoming a multi-planetary civilization? Image Credit: NASA
    The Artemis program is a renewed effort to establish a presence on the Moon. After that, we could visit Mars. Are these our first steps to becoming a multi-planetary civilization? Image Credit: NASA

    The second conclusion concerns legislating and governing AI, a difficult task in a world where psychopaths can gain control of entire nations and are bent on waging war. “While industry stakeholders, policymakers, individual experts, and their governments already warn that regulation is necessary, establishing a regulatory framework that can be globally acceptable is going to be challenging,” Garrett writes. Challenging barely describes it. Humanity’s internecine squabbling makes it all even more unmanageable. Also, no matter how quickly we develop guidelines, ASI might change even more quickly.

    “Without practical regulation, there is every reason to believe that AI could represent a major threat to the future course of not only our technical civilization but all technical civilizations,” Garrett writes.

    This is the United Nations General Assembly. Are we united enough to constrain AI? Image Credit: By Patrick Gruban, cropped and downsampled by Pine - originally posted to Flickr as UN General Assembly, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4806869
    This is the United Nations General Assembly. Are we united enough to constrain AI? Image Credit: By Patrick Gruban, cropped and downsampled by Pine – originally posted to Flickr as UN General Assembly, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4806869

    Many of humanity’s hopes and dreams crystallize around the Fermi Paradox and the Great Filter. Are there other civilizations? Are we in the same situation as other ETIs? Will our species leave Earth? Will we navigate the many difficulties that face us? Will we survive?

    If we do, it might come down to what can seem boring and workaday: wrangling over legislation.

    “The persistence of intelligent and conscious life in the universe could hinge on the timely and effective implementation of such international regulatory measures and technological endeavours,” Garrett writes.

    The post Does the Rise of AI Explain the Great Silence in the Universe? appeared first on Universe Today.

  • If We Want to Visit More Asteroids, We Need to Let the Spacecraft Think for Themselves
    by Andy Tomaswick on April 8, 2024 at 4:22 pm

    Missions to asteroids have been on a tear recently. Visits by Rosetta, Osirix-REX, and Hayabusa2 have all visited small bodies and, in some cases, successfully returned samples to the Earth. But as humanity starts reaching out to asteroids, it will run into a significant technical problem – bandwidth. There are tens of thousands of asteroids in our vicinity, some of which could potentially be dangerous. If we launched a mission to collect necessary data about each of them, our interplanetary communication and control infrastructure would be quickly overwhelmed. So why not let our robotic ambassadors do it for themselves – that’s the idea behind a new paper from researchers at the Federal University of São Paulo and Brazil’s National Institute for Space Research.

    The paper primarily focuses on the control problem of what to do when a spacecraft is approaching a new asteroid. Current missions take months to approach and require consistent feedback from ground teams to ensure the spacecraft understands the parameters of the asteroid it’s approaching – especially the gravitational constant.

    Some missions have seen more success with that than others – for example, Philase, the lander that went along with Rosetta, had trouble when it bounced off the surface of comet 67P/Churyumov-Gerasimenko. As the authors pointed out, part of that difference was a massive discrepancy between the actual shape of the comet and the observed shape that telescopes had seen before Rosetta arrived there. 

    Fraser discusses the possibility of capturing an asteroid.

    Even more successful missions, such as OSIRIS-Rex, take months of lead-up time to complete relatively trivial maneuvers in the context of millions of kilometers their overall journey takes them. For example, it took 20 days for OSIRIX-Rex to perform multiple flybys at 7 km above the asteroid’s surface before its mission control deemed it safe to enter a stable orbit.

    One of the significant constraints the mission controllers were looking at was whether they could accurately calculate the gravitational constant of the asteroid they were visiting. Gravity is notoriously difficult to determine from far away, and its miscalculation led to the problems with Philae. So, can a control scheme do to solve all of these problems?

    Simply put, it can allow the spacecraft to decide what to do when approaching their target. With a well-defined control scheme, the likelihood of a spacecraft failure due to some unforeseen consequence is relatively minimal. It could dramatically decrease the time missions spend on approach and limit the communication bandwidth back toward mission control on Earth. 

    One use case for quick asteroid mission – mining them, as Fraser discusses here.

    Such a scheme would also require only four relatively ubiquitous, inexpensive sensors to operate effectively – a LiDAR (similar to those found on autonomous cars), two optical cameras for depth perception, and an inertial measurement unit (IMU) that measures parameters like orientation, acceleration, and magnetic field. 

    The paper spends plenty of time detailing the complex math that would go into the control schema – some of which involve statistical calculations similar to basic learning models. The authors also run trials on two potential asteroid targets of interest to see how the system would perform.

    One is already well understood. Bennu was the target of the OSIRIX-Rex mission and, therefore, is well-characterized as asteroids go. According to the paper, with the new control system, a spacecraft could enter a 2000 m orbit within a day of approaching from hundreds of kilometers away, then enter an 800 m orbit the next day. This is compared to the months of preparatory work the actual OSIRIS-Rex mission had to accomplish. And it can be completed with minimal thrust and, more importantly, fuel – a precious commodity on deep-space missions.

    Asteroid defense is another important use case for quick asteroid missions – as Isaac Arthus discusses in this video.
    Credit – Isaac Arthur

    Another demonstration mission is one to Eros, the second-largest asteroid near Earth. It has a unique shape for an asteroid, as it is relatively elongated, which could pose an exciting challenge for automated systems like those described in the paper. Controlling a spacecraft with the new schema for a rendezvous with Eros doesn’t have all the same advantages of a more traditional asteroid like Bennu. For example, it has a much higher thrust requirement and fuel consumption. However, it still shortens the mission time and bandwidth required to operate it.

    Autonomous systems are becoming increasingly popular on Earth and in space. Papers like this one push the thinking about what is possible forward. Suppose all that’s required to eliminate months of painstaking manual technical work is to slap a few sensors and implement a new control algorithm. In that case, it’s likely that one of the various agencies and companies planning to rendezvous with an asteroid shortly will adopt that plan.

    Learn More:
    Negri et al. – Autonomous Rapid Exploration in Close-Proximity of an Asteroid
    UT – Miniaturized Jumping Robots Could Study An Asteroid’s Gravity
    UT – How to Make Asteroid Landings Safer
    UT – A Spacecraft Could use Gravity to Prevent a Dangerous Asteroid Impact

    Lead Image:
    Artist’s conception of the Lucy mission to the Trojan asteroids.
    Credit – NASA

    The post If We Want to Visit More Asteroids, We Need to Let the Spacecraft Think for Themselves appeared first on Universe Today.

  • Testing a Probe that Could Drill into an Ice World
    by Mark Thompson on April 8, 2024 at 4:12 pm

    I remember reading about an audacious mission to endeavour to drill through the surface ice of Europa, drop in a submersible and explore the depths below. Now that concept may be taking a step closer to reality with researchers working on technology to do just that. Worlds like Europa are high on the list for exploration due to their potential to harbour life. If technology like the SLUSH probe (Search for Life Using Submersible Head) work then we are well on the way to realising that dream. 

    The search for life has always been something to captivate the mind. Think about the diversity of life on Earth and it is easy to see why we typically envisage creatures that rely upon sunlight, food and drink. But on Earth, life has found a way in the most inhospitable of environments, even at the very bottom of the ocean. The Mariana’s Trench is deeper than Mount Everest is tall and anything that lives there has to cope with cold water, crushingly high pressure and no sunlight. Seems quite alien but even here, life thrives such as the deep-sea crustacean Hirondellea Gigas – catchy name. 

    Location of the Mariana Trench. Credit: Wikipedia Commons/Kmusser

    Europa, one of the moon’s of Jupiter has an ice crust but this covers over a global ocean of liquid water.  The conditions deep down in the ocean of Europa might not be so very different from those at the bottom of the Mariana’s Trench so it is here that a glimmer of hope exists to find other life in the Solar System. Should it exist, getting to it is the tricky bit. It’s not just on Europa but Enceladus and even Mars may have water underneath ice shelves. Layers of ice up to a kilometre thick might exist so technology like SLUSH has been developed to overcome. 

    Natural color image of Europa obtained by NASA’s Juno spacecraft. (Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill)

    The technology is not too new though since melt probes like SLUSH have been tested before. The idea is beautifully simple.  The thermo-mechanical probe uses a drilling mechanism to break through the ice and then the heat probe to partially melt the ice chips, forming slush to enable their transportation to behind the probe as it descends. 

    The probe, which looks rather like a light sabre, is then able to transmit data from the subsurface water back to the lander. A tether system is used for the data transmission using conductive microfilaments and an optical fibre cable. Intriguingly and perhaps even cunningly, should the fibre cable break (which is a possibility due to tidal stresses from the ice) then the microfilaments will work as an antenna.  They can then be tuned into by the lander to resume data transmission. The tether is coiled up and housed inside spools which are left behind in the ice as the spool is emptied. I must confess my immediate thought here was ‘litter’! I accept we have to leave probes in order to explore but surely we can do it without leaving litter behind! However there is a reason for this too. As the spools are deployed, they act as receivers and transmitters to allow the radio frequencies to travel through the ice. 

    The company working on the device is Honeybee Robotics have created prototypes. The first was stand alone, had no data transmission capability and demonstrated the drilling and slushing technology in an ice tower in Honeybee’s walk in freezer. While this was underway, the tether communication technology was being tested too with the first version called the Salmon Probe. This was taken to Devon Island in the Arctic where the unspooling method is being put through its paces. The first attempts back in 2022 saw the probe achieving depths of 1.8m! 

    A further probe was developed called the Dolphin probe and this was capable of getting to depths of about 100m but sea ice limitations meant it could only get to a depth of 2m! Thus far, all probes have performed well. Honeybee are now working on the Narwhal Probe which will have more measuring equipment on board, a deployable tether and spool and will be far more like the finished product. If all goes to plan it will profile the ice on Devon Island to a depth of 100m.  This is still quite short of the kilometre thick ice expected but it is most definitely fantastic progress toward exploring the cold watery depths of alien worlds. 

    Source : SLUSH: AN ICE DRILLING PROBE TO ACCESS OCEAN WORLDS

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