Space And The Universe News

by Nancy Atkinson on May 7, 2024 at 12:34 pm

The Sun is increasing its intensity on schedule, continuing its approach to solar maximum. In just over a 24-hour period on May 5 and May 6, 2024, the Sun released three X-class solar flares measuring at X1.3, X1.2, and X4.5. Solar flares can impact radio communications and electric power grids here on Earth, and they also pose a risk to spacecraft and astronauts in space.

NASA released an animation that shows the solar flares blasting off the surface of the rotating Sun, below.

Predicting when solar maximum will occur is not easy and the timing of it can only be confirmed after it happens. But NOAA’s Space Weather Prediction Center (SWPC) currently estimates that solar maximum will likely occur between May 2024 and early 2026. The Sun goes through a cycle of high and low activity approximately every 11 years, driven by the Sun’s magnetic field and indicated by the frequency and intensity of sunspots and other activity on the surface. The SWPC has been working hard to have a better handle on predicting solar cycles and activity. Find out more about that here.  

Solar flares are explosions on the Sun that release powerful bursts of energy and radiation coming from the magnetic energy associated with the sunspots. The more sunspots, the greater potential for flares.

Flares are classified based on a system similar to the Richter scale for earthquakes, which divides solar flares according to their strength. X-class is the most intense category of flares, while the smallest ones are A-class, followed by B, C, M and then X. Each letter represents a 10-fold increase in energy output. So an X is ten times an M and 100 times a C. The number that follows the letter provides more information about its strength. The higher the number, the stronger the flare.

Flares are our solar system’s largest explosive events. They are seen as bright areas on the Sun and can last from minutes to hours. We typically see a solar flare by the photons (or light) it releases, occurring in various wavelengths.

Sometimes, but not always, solar flares can be accompanied by a coronal mass ejection (CME), where giant clouds of particles from the Sun are hurled out into space.  If we’re lucky, these charged particles will provide a stunning show of auroras here on Earth while not impacting power grids or satellites.

Thankfully, missions like the Solar Dynamics Observatory, Solar Orbiter, the Parker Solar Probe are providing amazing views and new details about the Sun, helping astronomers to learn more about the dynamic ball of gas that powers our entire Solar System.

The post Solar Max is Coming. The Sun Just Released Three X-Class Flares appeared first on Universe Today.

by Evan Gough on May 7, 2024 at 1:10 am

Does another undetected planet languish in our Solar System’s distant reaches? Does it follow a distant orbit around the Sun in the murky realm of comets and other icy objects? For some researchers, the answer is “almost certainly.”

The case for Planet Nine (P9) goes back at least as far as 2016. In that year, astronomers Mike Brown and Konstantin Batygin published evidence pointing to its existence. Along with colleagues, they’ve published other work supporting P9 since then.

There’s lots of evidence for the existence of P9, but none of it has reached the threshold of definitive proof. The main evidence concerns the orbits of Extreme Trans-Neptunian Objects (ETNOs). They exhibit a peculiar clustering that indicates a massive object. P9 might be shepherding these objects along on their orbits.

The names Brown and Batygin, both Caltech astronomers, come up often in regard to P9. Now, they’ve published another paper along with colleagues Alessandro Morbidelli and David Nesvorny, presenting more evidence supporting P9.

It’s titled “Generation of Low-Inclination, Neptune-Crossing TNOs by Planet Nine.” It’s published in The Astrophysical Journal Letters.

“The solar system’s distant reaches exhibit a wealth of anomalous dynamical structure, hinting at the presence of a yet-undetected, massive trans-Neptunian body—Planet Nine (P9),” the authors write. “Previous analyses have shown how orbital evolution induced by this object can explain the origins of a broad assortment of exotic orbits.”

To dig deeper into the issue, Batygin, Brown, Morbidelli, and Nesvorny examined Trans-Neptunian Objects (TNOs) with more conventional orbits. They carried out N-body simulations of these objects that included everything from the tug of giant planets and the Galactic Tide to passing stars.

29 objects in the Minor Planet Database have well-characterized orbits with a > 100 au, inclinations < 40°, and q (perihelia) < 30 au. Of those 29, 17 have well-quantified orbits. The researchers focused their simulations on these 17.

The researchers’ goal was to analyze these objects’ origins and determine if they could be used as a probe for P9. To accomplish this, they conducted two separate sets of simulations. One set with P9 in the Solar System and one set without.

The simulations began at t=300 million years, meaning 300 million years into the Solar System’s existence. At that time, “intrinsic dynamical evolution in the outer solar system is still in its infancy,” the authors explain, while enough time has passed for the Solar System’s birth cluster of stars to disperse and for the giant planets to have largely concluded their migrations. They ended up with about 2000 objects, or particles, in the simulation with perihelia greater than 30 au and semimajor axes between 100 and 5000 au. This ruled out all Neptune-crossing objects from the simulation’s starting conditions. “Importantly, this choice of initial conditions is inherently linked with the assumed orbit of P9,” they point out.

The figure below shows the evolution of some of the 2,000 objects in the simulations.

These are interesting results, but the researchers point out that they in no way prove the existence of P9. These orbits could be generated by other things like the Galactic Tide. In their next step, they examined their perihelion distribution.

“Accounting for observational biases, our results reveal that the orbital architecture of this group of objects aligns closely with the predictions of the P9-inclusive model,” the authors write. “In stark contrast, the P9-free scenario is statistically rejected at a ~5? confidence level.”

The authors point out that something other than P9 could be causing the orbital unruliness. The star was born in a cluster, and cluster dynamics could’ve set these objects on their unusual orbits before the cluster dispersed. A number of Earth-mass rogue planets could also be responsible, influencing the outer Solar System’s architecture for a few hundred million years before being removed somehow.

However, the authors chose their 17 TNOs for a reason. “Due to their low inclinations and perihelia, these objects experience rapid orbital chaos and have short dynamical lifetimes,” the authors write. That means that whatever is driving these objects into these orbits is ongoing and not a relic from the past.

An important result of this work is that it results in falsifiable predictions. And we may not have to wait long for the results to be tested. “Excitingly, the dynamics described here, along with all other lines of evidence for P9, will soon face a rigorous test with the operational commencement of the VRO (Vera Rubin Observatory),” the authors write.

If P9 is real, what is it? It could be the core of a giant planet ejected during the Solar System’s early days. It could be a rogue planet that drifted through interstellar space until being caught up in our Solar System’s gravitational milieu. Or it could be a planet that formed on a distant orbit, and a passing star shepherded it into its eccentric orbit. If astronomers can confirm P9’s existence, the next question will be, ‘what is it?’

If you’re interested at all in how science operates, the case of P9 is very instructive. Eureka moments are few and far between in modern astronomy. Evidence mounts incrementally, accompanied by discussion and counterpoint. Objections are raised and inconsistencies pointed out, then methods are refined and thinking advances. What began as one over-arching question is broken down into smaller, more easily-answered ones.

But the big question dominates for now and likely will for a while longer: Is there a Planet Nine?

Stay tuned.

The post New Evidence for Our Solar System’s Ghost: Planet Nine appeared first on Universe Today.

by Evan Gough on May 6, 2024 at 9:37 pm

It’s that time again. NIAC (NASA Innovative Advanced Concepts) has announced six concepts that will receive funding and proceed to the second phase of development. This is always an interesting look at the technologies and missions that could come to fruition in the future.

The six chosen ones will each receive $600,000 in funding to pursue the ideas for the next two years. NASA expects each team to use the two years to address both technical and budgetary hurdles for their concepts. When this second phase comes to an end, some of the concepts could advance to the third stage.

“These diverse, science fiction-like concepts represent a fantastic class of Phase II studies,” said John Nelson, NIAC program executive at NASA Headquarters in Washington. “Our NIAC fellows never cease to amaze and inspire, and this class definitely gives NASA a lot to think about in terms of what’s possible in the future.”

Here they are.

Fluidic Telescope (FLUTE): Enabling the Next Generation of Large Space Observatories

Telescopes are built around mirrors and lenses, whether they’re ground-based or space-based. The JWST’s large mirror is 6.5 meters in diameter but had to be folded up to fit inside the rocket that launched it and then unfolded in space. That’s a tricky engineering feat. Engineers are building larger and larger ground-based telescopes, too, and they’re equally tricky to design and build. Could FLUTE change this?

FLUTE envisions lenses made of fluid, and the FLUTE team’s concept describes a space telescope with a primary mirror 50 meters (164 ft.) in diameter. Creating glass lenses for a telescope this large isn’t realistic. “Using current technologies, scaling up space telescopes to apertures larger than approximately 33 feet (10 meters) in diameter does not appear economically viable,” the FLUTE website states.

But in the microgravity of space, fluids behave in an intriguing way. Surface tension holds liquids together at their surfaces. We can see this on Earth, where some insects use surface tension to glide along the surfaces of ponds and other bodies of water. Also, on Earth, surface tension holds small drops of water together. But in space, away from Earth’s dominating gravity, surface tension is much more effective. There, water maintains the most energy efficient shape there is: a sphere.

Another force governs water: adhesion. Adhesion causes liquids to cling to surfaces. In the microgravity of space, adhesion can bind liquid to a circular, ring-like frame. Then, due to surface tension, the liquid will naturally adopt a spherical shape. If the liquid can be made to bulge inward rather than outward, and if the liquid is reflective enough, it creates a telescope mirror.

The FLUTE team would like to make optical components in space. The liquid would stay in the liquid state and form an extremely smooth light-collecting surface. As a bonus, FLUTE would also self-repair after any micrometeorite strike.

The FLUTE study is led by Edward Balaban from NASA’s Ames Research Center in California’s Silicon Valley. The FLUTE team has already done some tests on the ISS and on zero-g flights.

Pulsed Plasma Rocket (PPR): Shielded, Fast Transits for Humans to Mars

It takes too long to get to Mars. It’s a six-month journey each way, plus time spent on the surface. All that time in microgravity, exposure to radiation, and other challenges make the trip very difficult for astronauts. PPR aims to fix that.

PPR isn’t a launch vehicle for escaping Earth’s gravity well. It would be launched on a heavy lift vehicle like SLS and then sent on its way.

PPR was originally derived from the Pulsed Fission Fusion concept. But it’s more affordable, and also smaller and simpler. PPR might generate 100,000 N of thrust with a specific impulse (Isp) of 5,000 seconds. Those are good numbers. PPR could reduce the travel time to Mars to two months.

It has other benefits as well. It could propel larger spacecraft to Mars on trips longer than two months, carrying more cargo and also provide heavier shielding against cosmic rays. “The PPR enables a whole new era in space exploration,” the team writes.

PPR is basically a fusion system ignited by fission. It’s similar to a thermonuclear weapon. But rather than a run-away explosion, the combined energy is directed through a magnetic nozzle to produce thrust.

In phase two, the PPR team intends to optimize the engine design to produce more specific impulse, perform proof-of-concept experiments for major components, and design a shielded ship for human missions to Mars.

This study is led by Brianna Clements with Howe Industries in Scottsdale, Arizona.

The Great Observatory for Long Wavelengths (GO-LoW)

One of modern astronomy’s last frontiers is the low-frequency radio sky. Earth’s ionosphere blocks our ground-based telescopes from seeing it. And space-based telescopes can’t see it either. It’s because the wavelengths are so long, in the meter to the kilometre scale. Only extremely massive telescopes could see these waves clearly.

GO-LoW is a potential solution. It’s a space-based array of thousands of identical Small-Sats arranged as an interferometer. It would sit at an Earth-Sun Lagrange point and observe exoplanet and stellar magnetic fields. Exoplanet magnetic fields emit radio waves between 100 kHz and 15 MHz. The GO-LoW team says their interferometer could perform the first survey of exoplanetary magnetic fields within 5 parsecs (16 light years.) Magnetic fields tell scientists a lot about an exoplanet, its evolution, and its processes.

While there’s no doubt that large telescopes like the JWST are powerful and effective, they’re extremely complex and expensive. And if something goes wrong with a critical component, the mission could end.

GO-LoW takes a different approach. By using thousands of individual satellites, the system is more resilient. GO-LoW would have a hybrid constellation. Some of the satellites would be smaller and simpler satellites called “listener nodes” (LN,) while a smaller number of them would be “communication and computation” nodes (CCNs). They would collect data from the LNs, process it, and beam it back to Earth.

The GO-LoW says it would only take a few heavy launches to place an entire 100,000 satellite constellation in space.

The technology for the SmallSats already exists. The challenge the GO-LoW team will address with their phase two funding is developing a system that will harness everything together effectively. “The coordination of all these physical elements, data products, and communications systems is novel and challenging, especially at scale,” they write.

GO-LoW is led by Mary Knapp with MIT in Cambridge, Massachusetts.

Radioisotope Thermoradiative Cell Power Generator

It’s sort of like solar power in reverse.

The RTCPG is a power source for spacecraft visiting the outer planets. They promise smaller, more efficient power generation for smaller science and exploration missions that can’t carry a solar power system or nuclear power system. Both those systems are bulky, and solar power is limited the further away from the sun a spacecraft goes.

The thermoradiative cell (TRC) uses radioisotopes to create heat as an MMRTG does. But the TRC uses the heat to generate infrared light which generates electricity. In initial testing, the system generated 4.5 times more power from the same amount of PU-238.

Much of phase two’s work will involve materials. “Metal-semiconductor contacts capable of surviving the required elevated temperatures will be investigated,” the team explains. The team developed a special cryostat testing apparatus in phase one.

“Building on our results from Phase I, we believe there is much more potential to unlock here,” the team writes.

This power generation concept study is from Stephen Polly at the Rochester Institute of Technology in New York.

FLOAT: Flexible Levitation on a Track

What if Artemis is enormously successful? How will astronauts move their equipment around the lunar surface efficiently?

FLOAT would provide autonomous transportation for payloads on the Moon. “A durable, long-life robotic transport system will be critical to the daily operations of a sustainable lunar base in the 2030’s,” the FLOAT team writes.

The heart of FLOAT is a three-layer flexible track that’s unrolled into position without major construction. It consists of three layers: a graphite layer, a flex-circuit layer, and a solar panel layer.

The graphite layer allows robots to use diamagnetic levitation to float over the track. The flex-circuit layer supplies the thrust that moves them, and the thin-film solar panel layer generates electricity for a lunar base when it’s in sunlight.

The system can be used to move regolith around for in-situ resource utilization and to transport payloads around a lunar base, for example, from landing zones to habitats.

“Individual FLOAT robots will be able to transport payloads of varying shape/size (>30 kg/m^2) at useful speeds (>0.5m/s), and a large-scale FLOAT system will be capable of moving up to 100,000s kg of regolith/payload multiple kilometres per day,” the FLOAT team explains.

With their phase two funding, the FLOAT team intends to design, build, and test scaled-down versions of FLOAT robots and track. Then, they’ll test their system in a lunar analog testbed. They’ll also test environmental effects on the system and how they alter the system’s performance and longevity.

Ethan Schaler leads FLOAT at NASA’s Jet Propulsion Laboratory in Southern California.

SCOPE: ScienceCraft for Outer Planet Exploration

Some of the most intriguing planets and moons in the Solar System are well beyond Jupiter. But exploring them is challenging. Extremely long travel times, restrictive mission windows, and large expenses limit our exploration. But SCOPE aims to address these limitations.

Typically, a spacecraft carries a propulsion and power system along with its instruments and communication systems. NASA’s Juno mission to Jupiter, for example, carries a chemical rocket engine for propulsion, 50 square meters of solar panels, and 10 science instruments. The solar panels alone weigh 340 kg (750 lbs.) Juno is powerful, produces a wide variety of quality science data, and is expensive.

ScienceCraft takes a different approach. It combines a single science instrument and spacecraft into one monolithic structure. It’s basically a solar sail with a built-in spectrometer. They’re aiming their design at the Neptune-Triton system.

“By printing an ultra-lightweight quantum dot-based spectrometer, developed by the PI Sultana, directly on the solar sail, we create a breakthrough spacecraft architecture allowing an unprecedented parallelism and throughput of data collection and rapid travel across the solar system,” the ScienceCraft team writes.

Instead of merely providing the propulsion, the sail doubles as the spacecraft’s science instrument. The small mass means that ScienceCraft could be carried into orbit as a secondary payload. The team says they’ll use phase two to identify and develop key technologies for the spacecraft and to further mature the mission concept. They say that because of the low cost and simplicity, they could be ready by 2045.

“By leveraging these benefits, we propose a mission concept to Triton, a unique planetary body in our solar system, within the short window that closes around 2045 to answer compelling science questions about Triton’s atmosphere, ionosphere, plumes and internal structure,” the ScienceCraft team explains.

ScienceCraft is led by NASA’s Mahmooda Sultana at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.

The post NASA Takes Six Advanced Tech Concepts to Phase II appeared first on Universe Today.

by Matt Williams on May 6, 2024 at 7:12 pm

On Friday, May 3rd, the sixth mission in the Chinese Lunar Exploration Program (Chang’e-6) launched from the Wenchang Spacecraft Launch Site in southern China. Shortly after, China announced that the spacecraft separated successfully from its Long March 5 Y8 rocket. The mission, consisting of an orbiter and lander element, is now on its way to the Moon and will arrive there in a few weeks. By June, the lander element will touch down on the far side of the Moon, where it will gather about 2 kg (4.4 lbs) of rock and soil samples for return to Earth.

The mission launched four years after its predecessor, Chang’e-5, became China’s first sample-return mission to reach the Moon. It was also the first lunar sample return mission since the Soviet Luna 24 mission landed in Mare Crisium (the Sea of Crisis) in 1976. Compared to its predecessor, the Chang’e-6 mission weighs an additional 100 kg (220 lbs), making it the heaviest probe launched by the Chinese space program. The surface elements also face lesser-known terrain on the far side of the Moon and require a relay satellite for communications.

Speaking of surface elements, the China Academy of Space Technology (CAST) has since released images showing how the mission also carries a rover element. This payload was not part of mission data disclosed by China before the flight. But as SpaceNews’ Andrew Jones pointed out, the rover can be seen in the CAST images (see above) integrated onto the side of the lander.

Yeah, okay. That looks like a previously undisclosed mini rover on the side of the Chang'e-6 lander lol. Via CAST: https://t.co/gS0Jy5L9hw pic.twitter.com/9vvTnribpl

— Andrew Jones (@AJ_FI) May 3, 2024

“Little is known about the rover, but a mention of a Chang’e-6 rover is made in a post from the Shanghai Institute of Ceramics (SIC) under the Chinese Academy of Sciences (CAS),” he wrote. “It suggests the small vehicle carries an infrared imaging spectrometer.” This rover is no doubt intended to assist the lander with investigating resources on the far side of the Moon. This is consistent with China’s long-term plans for building the International Lunar Research Station (ILRS) around the southern polar region in collaboration with Roscosmos and other international patterns.

Similar to NASA’s plans for the Lunar Gateway and Artemis Base Camp, this requires that building sites be selected near sources of water ice and building materials (silica and other minerals). Ge Ping, the deputy director of the Center of Lunar Exploration and Space Engineering (CLESE) with the China National Space Administration (CNSA), related the importance of the sample-return mission to CGTN (a state-owned media company) before the launch:

“The Aitken Basin is one of the three major terrains on the Moon and has significant scientific value. Finding and collecting samples from different regions and ages of the Moon is crucial for our understanding of it. These would further study of the moon’s origin and its evolutionary history.”

In addition, the Chang’e-6 orbiter carries four international payloads and satellites including a French radon detector contributed by the ESA. Known as the Detection of Outgassing Radon (DORN), this payload will study how lunar dust and other volatiles (especially water) are transferred between the lunar regolith and the lunar exosphere. Then there’s the Italian INstrument for landing-Roving laser Retroreflector Investigations (INRRI), similar to those used by the Schiaparelli EDM module and InSight lander, that precisely measures distances from the lander to orbit.

There’s also the Swedish Negative Ions on Lunar Surface (NILS), an instrument that will detect and measure negative ions reflected by the lunar surface. Lastly, there’s the Pakistani ICUBE-Q CubeSat developed by the Institute of Space Technology (IST) and Shanghai Jiao Tong University (SJTU), which will take images of the lunar surface using two optical cameras and measure the Moon’s magnetic field. The data these instruments provide will reveal new information about the lunar environment that will inform plans for long-duration missions on the surface.

By 2026, the Chang’e-6 mission will be joined by Chang’e-7, including an orbiter, lander, rover, and a mini-hopping probe. The data provided by the program will assist China’s plans to land taikonauts around the lunar south pole by 2030, followed by the completion of the ILRS by 2035.

Further Reading: CGTN

The post China is Going Back to the Moon Again With Chang'e-6 appeared first on Universe Today.

by Evan Gough on May 6, 2024 at 7:06 pm

Earth is the only life-supporting planet we know of, so it’s tempting to use it as a standard in the search for life elsewhere. But the modern Earth can’t serve as a basis for evaluating exoplanets and their potential to support life. Earth’s atmosphere has changed radically over its 4.5 billion years.

A better way is to determine what biomarkers were present in Earth’s atmosphere at different stages in its evolution and judge other planets on that basis.

That’s what a group of researchers from the UK and the USA did. Their research is titled “The early Earth as an analogue for exoplanetary biogeochemistry,” and it appears in Reviews in Mineralogy. The lead author is Eva E. Stüeken, a PhD student at the School of Earth & Environmental Sciences, University of St Andrews, UK.

When Earth formed about 4.5 billion years ago, its atmosphere was nothing like it is today. At that time, the atmosphere and oceans were anoxic. About 2.4 billion years ago, free oxygen began to accumulate in the atmosphere during the Great Oxygenation Event, one of the defining periods in Earth’s history. But the oxygen came from life itself, meaning life was present when the Earth’s atmosphere was much different.

This isn’t the only example of how Earth’s atmosphere has changed over geological time. But it’s an instructive one and shows why searching for life means more than just searching for an atmosphere like modern Earth’s. If that’s the way we conducted the search, we’d miss worlds where photosynthesis hadn’t yet appeared.

In their research, the authors point out how Earth hosted a rich and evolving population of microbes under different atmospheric conditions for billions of years.

“For most of this time, Earth has been inhabited by a purely microbial biosphere albeit with seemingly increasing complexity over time,” the authors write. “A rich record of this geobiological evolution over most of Earth’s history thus provides insights into the remote detectability of microbial life under a variety of planetary conditions.”

It’s not just life that’s changed over time. Plate tectonics have changed and may have been ‘stagnant lid’ tectonics for a long time. In stagnant lid tectonics, plates don’t move horizontally. That can have consequences for atmospheric chemistry.

The main point is that Earth’s atmosphere does not reflect the solar nebula the planet formed in. Multiple intertwined processes have changed the atmosphere over time. The search for life involves not only a better understanding of these processes, but how to identify what stage exoplanets might be in.

It’s axiomatic that biological processes can have a dramatic effect on planetary atmospheres. “On the modern Earth, the atmospheric composition is very strongly controlled by life,” the researchers write. “However, any potential atmospheric biosignature must be disentangled from a backdrop of abiotic (geological and astrophysical) processes that also contribute to planetary atmospheres and would be dominating on lifeless worlds and on planets with a very small biosphere.”

The authors outline what they say are the most important lessons that the early Earth can teach us about the search for life.

The first is that the Earth has actually had three different atmospheres throughout its long history. The first one came from the solar nebula and was lost soon after the planet formed. That’s the primary atmosphere. The second one formed from outgassing from the planet’s interior. The third one, Earth’s modern atmosphere, is complex. It’s a balancing act involving life, plate tectonics, volcanism, and even atmospheric escape. A better understanding of how Earth’s atmosphere has changed over time gives researchers a better understanding of what they see in exoplanet atmospheres.

The second is that the further we look back in time, the more the rock record of Earth’s early life is altered or destroyed. Our best evidence suggests life was present by 3.5 billion years ago, maybe even by 3.7 billion years ago. If that’s the case, the first life may have existed on a world covered in oceans, with no continental land masses and only volcanic islands. If there had been abundant volcanic and geological activity between 3.5 and 3.7 billion years ago, there would’ve been large fluxes of CO2 and H2. Since these are substrates for methanogenesis, then methane may have been abundant in the atmosphere and detectable.

The third lesson the authors outline is that a planet can host oxygen-producing life for a long time before oxygen can be detected in an atmosphere. Scientists think that oxygenic photosynthesis appeared on Earth in the mid-Archean eon. The Archean spanned from 4 billion to 2.5 billion years ago, so mid-Archean is sometime around 3.25 billion years ago. But oxygen couldn’t accumulate in the atmosphere until the Great Oxygenation Event about 2.4 billion years ago. Oxygen is a powerful biomarker, and if we find it in an exoplanet’s atmosphere, it would be cause for excitement. But life on Earth was around for a long time before atmospheric oxygen would’ve been detectable.

The fourth lesson involves the appearance of horizontal plate tectonics and its effect on chemistry. “From the GOE onwards, the Earth looked tectonically similar to today,” the authors write. The oceans were likely stratified into an anoxic layer and an oxygenated surface layer. However, hydrothermal activity constantly introduced ferrous iron into the oceans. That increased the sulphate levels in the seawater which reduced the methane in the atmosphere. Without that methane, Earth’s biosphere would’ve been much less detectable. Complicated, huh?

“Planet Earth has evolved over the past 4.5 billion years from an entirely anoxic planet
with possibly a different tectonic regime to the oxygenated world with horizontal plate
tectonics that we know today,” the authors explain. All that complex evolution allowed life to appear and to thrive, but it also makes detecting earlier biospheres on exoplanets more complicated.

We’re at a huge disadvantage in the search for life on exoplanets. We can literally dig into Earth’s ancient rock to try to untangle the long history of life on Earth and how the atmosphere evolved over billions of years. When it comes to exoplanets, all we have is telescopes. Increasingly powerful telescopes, but telescopes nonetheless. While we are beginning to explore our own Solar System, especially Mars and the tantalizing ocean moons orbiting the gas giants, other solar systems are beyond our physical reach.

“We must instead remotely recognize the presence of alien biospheres and characterize their biogeochemical cycles in planetary spectra obtained with large ground- and space-based telescopes,” the authors write. “These telescopes can probe atmospheric composition by detecting absorption features associated with specific gases.” Probing atmospheric gases is our most powerful approach right now, as the JWST shows.

But as scientists get better tools, they’ll start to go beyond atmospheric chemistry. “We might also be able to recognize global-scale surface features, including light interaction with photosynthetic pigments and ‘glint’ arising from specular reflection of light by a liquid ocean.”

Understanding what we’re seeing in exoplanet atmospheres parallels our understanding of Earth’s long history. Earth could be the key to our broadening and accelerating search for life.

“Unravelling the details of Earth’s complex biogeochemical history and its relationship with remotely observable spectral signals is an important consideration for instrument design and our own search for life in the Universe,” the authors write.

The post What Can Early Earth Teach Us About the Search for Life? appeared first on Universe Today.

by Matt Williams on May 5, 2024 at 11:04 pm

Multiple space agencies are looking to send crewed missions to the Moon’s southern polar region in this decade and the next. Moreover, they intend to create the infrastructure that will allow for a sustained human presence, exploration, and economic development. This requires that the local geography, resources, and potential hazards be scouted in advance and navigation strategies that do not rely on a Global Positioning System (GPS) developed. On Sunday, April 21st, the Chinese Academy of Sciences (CAS) released the first complete high-definition geologic atlas of the Moon.

This 1:2.5 million scale geological set of maps provides basic geographical data for future lunar research and exploration. According to the Institute of Geochemistry of the Chinese Academy of Sciences (CAS), the volume includes data on 12,341 craters, 81 impact basins, 17 types of lithologies, 14 types of structures, and other geological information about the lunar surface. This data will be foundational to China’s efforts in selecting a site for their International Lunar Research Station (ILRS) and could also prove useful for NASA planners as they select a location for the Artemis Base Camp.

Ouyang Ziyuan and Liu Jianzhong, a research professor and senior researcher from the Institute of Geochemistry of the CAS (respectively), oversaw these efforts. Since 2012, they have led a team of over 100 scientists and cartographers from relevant research institutions. The team spent more than a decade compiling scientific exploration data obtained by the many orbiters, landers, and rovers that are part of the Chinese Lunar Exploration Program (Chang’e), and other research about the origin and evolution of the Moon.

According to the CAS, the atlas includes an “upgraded lunar geological time scale” for “objectively” depicting the geological evolution of the Moon, including the lunar tectonics and volcanic activity that once took place. As a result, the volume could not only be significant in terms of lunar exploration and site selection. Still, it could also improve our understanding of the formation and evolution of Earth and the other terrestrial planets of the Solar System – Mercury, Venus, and Mars. As Jianzhong indicated in a CAS press release,

“The world has witnessed significant progress in the field of lunar exploration and scientific research over the past decades, which have greatly improved our understanding of the moon. However, the lunar geologic maps published during the Apollo era have not been changed for about half a century and are still being used for lunar geological research. With the improvements of lunar geologic studies, those old maps can no longer meet the needs of future scientific research and lunar exploration.”

Jianzhong also claims that the atlas could help inform future sample collection on the Moon. This includes the Chang’e-6 mission (consisting of an orbiter and lander), which launched this past Friday (May 3rd). The orbiter element will reach the Moon in a few weeks, and the lander element is expected to touch down the far side of the Moon by early June. By 2026, it will be joined by the Chang’e-7 mission, consisting of an orbiter, lander, rover, and a mini-hopping probe. While Chang’e-6 will obtain lunar soil and rock samples, Chang’e-7 will investigate resources and obtain samples of water ice and volatiles.

According to Gregory Michael, a senior scientist from the Free University of Berlin, the release of this atlas represents the culmination of decades of work, and not just by Chinese scientists:

“This map, in particular, is the first on a global scale to utilize all of the post-Apollo era data. It builds on the achievements of the international community over the last decades, as well as on China’s own highly successful Chang’e program. It will be a starting point for every new question of lunar geology and become a primary resource for researchers studying lunar processes of all kinds.”

Aside from updating data on lunar features and geology, the new maps reportedly double the resolution of the Apollo-era maps. These maps were compiled by the US Geological Survey in the 1960s and 70s using data from the Apollo missions. Among them was a global map at the scale of 1:5,000,000, though other regional maps and those that showed the terrain near the Apollo landing sites were of higher resolution. Geological and geographical information on the Moon has advanced considerably since then, requiring updated maps that reflect the objective of returning to the Moon with the intent to stay.

In addition to the Geologic Atlas of the Lunar Globe, the CAS also released a book called Map Quadrangles of the Geologic Atlas of the Moon. This document includes 30 sector diagrams that collectively form a visualization of the entire lunar surface. Both are available in Chinese and English, have been integrated into a digital platform called Digital Moon, and will eventually become available to the international research community.

Further Reading: CAS

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by Matt Williams on May 4, 2024 at 9:54 pm

Last November, NASA’s Lucy mission conducted a flyby of the asteroid Dinkinish, one of the Main Belt asteroids it will investigate as it makes its way to Jupiter. In the process, the spacecraft spotted a small moonlet orbiting the larger asteroid, now named Selam (aka. “Lucy’s baby”). The moonlet’s name, an Ethiopian name that means “peace,” pays homage to the ancient human remains dubbed “Lucy” (or Dinkinish) that were unearthed in Ethiopia in 1974. Using novel statistical calculations based on how the two bodies orbit each other, a Cornell-led research team estimates that the moonlet is only 2-3 million years old.

The research was led by Colby Merrill, a graduate student from the Department of Mechanical and Aerospace Engineering at Cornell. He was joined by Alexia Kubas, a researcher from the Department of Astronomy at Cornell; Alex J. Meyer, a Ph.D. student at the UC Boulder College of Engineering & Applied Science; and Sabina D. Raducan, a Postdoctoral Researcher at the University of Bern. Their paper, “Age of (152830) Dinkinesh-Selam Constrained by Secular Tidal-BYORP Theory,” recently appeared on April 19th in Astronomy & Astrophysics.

Merrill was also part of the NASA Double Asteroid Redirection Test (DART) mission, which collided with the moonlet Dimorphos on September 26th, 2022. As part of the Lucy mission, Merrill was surprised to discover that Dinkinesh was also a binary asteroid when the spacecraft flew past it on November 1st, 2023. They were also fascinated to learn that the small moonlet was a “contact binary,” consisting of two lobes that are piles of rubble that became stuck together long ago.

While astronomers have observed contact binaries before – a good example is the KBO Arrokoth that the New Horizons spacecraft flew past on January 1st, 2019 – this is the first time one has been observed orbiting a larger asteroid. Along with Kubas, the two began modeling the system as part of their studies at Cornell to determine the age of the moonlet. Their results agreed with one performed by the Lucy mission based on an analysis of surface craters, the more traditional method for estimating the age of asteroids. As Merrill said in a recent Cornell Chronicle release:

“Finding the ages of asteroids is important to understanding them, and this one is remarkably young when compared to the age of the Solar System, meaning it formed somewhat recently. Obtaining the age of this one body can help us to understand the population as a whole.”

Binary asteroids are a subject of fascination to astronomers because of the complex dynamics that go into creating them. On the one hand, there are the gravitational forces working on them that cause them to bulge and lose energy. At the same time, binary systems will also experience what is known as the Binary Yarkovsky–O’Keefe–Radzievskii–Paddack (BYORP) effect, where exposure to solar radiation alters the rotation rate of the bodies. Eventually, these forces will balance out and reach a state of equilibrium for the system.

For their study, Merril and his team assumed that Selam formed from material ejected from Dinkinesh before the BYORP effect slowed its rotation down. They also assumed that the system had since reached a state of equilibrium and that the density of both objects was comparable. They then integrated asteroid data obtained by the Lucy mission to calculate how long it would take Selam to reach its current state. After performing about 1 million calculations with varying parameters, they obtained a median age estimate of 3 million years old, with 2 million being the most likely result.

This new method complements the previous age estimates of the Lucy mission and has several advantages. As their paper indicates, this method can yield age estimates based on asteroid dynamics alone and does not require close-up images taken by spacecraft. It could also be more accurate where asteroid surfaces experienced recent changes and can be applied to the moonlets of other known binary systems, which account for 15% of near-Earth asteroids (NEAs). This includes Didymos and Dimorphos, which are even younger.

The researchers hope to apply their new method to this and other binary systems where the dynamics are well-characterized, even without close flybys. Said Kubas:

“Used in tandem with crater counting, this method could help better constrain a system’s age. If we use two methods and they agree with each other, we can be more confident that we’re getting a meaningful age that describes the current state of the system.”

Further Reading: Cornell Chronicle

The post Dinkinesh's Moonlet is Only 2-3 Million Years Old appeared first on Universe Today.

by Brian Koberlein on May 4, 2024 at 4:19 pm

It’s that time again! Time for another model that will finally solve the mystery of dark matter. Or not, but it’s worth a shot. Until we directly detect dark matter particles, or until some model conclusively removes dark matter from our astrophysical toolkit the best we can do is continue looking for solutions. This new work takes a look at that old theoretical chestnut, primordial black holes, but it has a few interesting twists.

Primordial black holes are hypothetical objects formed during the earliest moments of the Universe. According to the models they formed from micro-fluctuations in matter density and spacetime to become sandgrain-sized mountain-massed black holes. Although we’ve never detected primordial black holes, they have all the necessary properties of dark matter, such as not emitting light and the ability to cluster around galaxies. If they exist, they could explain most of dark matter.

The downside is that most primordial black hole candidates have been ruled out by observation. For example, to account for dark matter there would have to be so many of these gravitational pipsqueaks that they would often pass in front of a star from our vantage point. This would create a microlensing flare we should regularly observe. Several sky surveys have looked for such an event to no avail, so PBH dark matter is not a popular idea these days.

This new work takes a slightly different approach. Rather than looking at typical primordial black holes, it considers ultralight black holes. These are on the small end of possible masses and are so tiny that Hawking radiation would come into play. The rate of Hawking decay is inversely proportional to the size of a black hole, so these ultralight black holes should radiate to their end of life on a short cosmic timescale. Since we don’t have a full model of quantum gravity, we don’t know what would happen to ultralight black holes at the end, which is where this paper comes in.

As the author notes, basically there are three possible outcomes. The first is that the black hole radiates away completely. The black hole would end as a brief flash of high-energy particles. The second is that some mechanism prevents complete evaporation and the black hole reaches some kind of equilibrium state. The third option is similar to the second, but in this case, the equilibrium state causes the event horizon to disappear, leaving an exposed dense mass known as a naked singularity. The author also notes that for the latter two outcomes, the objects might have a net electric charge.

For the evaporating case, the biggest unknown would be the timescale of evaporation. If PBHs are initially tiny they would evaporate quickly and add to the reheating effect of the early cosmos. If they evaporate slowly, we should be able to see their deaths as a flash of gamma rays. Neither of these effects has been observed, but it is possible that detectors such as Fermi’s Large Area Telescope might catch one in the act.

For the latter two options, the author argues that equilibrium would be reached around the Planck scale. The remnants would be proton sized but with much higher masses. Unfortunately, if these remnants are electrically neutral they would be impossible to detect. They wouldn’t decay into other particles, nor would they be large enough to detect directly. This would match observation, but isn’t a satisfying result. The model is essentially unprovable. If the particles do have a charge, then we might detect their presence in the next generation of neutrino detectors.

The main thing about this work is that primordial black holes aren’t entirely ruled out by current observations. Until we have better data, this model joins the theoretical pile of many other possibilities.

Reference: Profumo, S. “Ultralight Primordial Black Holes.” arXiv preprint arXiv:2405.00546 (2024).

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by Alan Boyle on May 4, 2024 at 2:43 am

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.

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by Evan Gough on May 3, 2024 at 8:51 pm

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.

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.

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.

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.

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.