Space, Planets and eclipses

[ghost2509]

A New Study Suggests Aliens Aren’t Little Green Men. They’re Purple People Eaters.

POPULAR MECHANICS
yahoo.com
Darren Orf
April 26, 2024

While the Earth is often called “the Pale Blue Dot” thanks to its bountiful oceans, most of the planet’s land masses are dominated by the color green. Plants use chlorophyll (which absorbs red and blue light but, reflects green light) to captures solar energy, and use carbon and water to make food through a process known as photosynthesis. While this fourth grade biology lesson outlines the predominant way plant life thrives on our planet, life on other Earth-like exoplanets (especially those orbiting red dwarf stars) could use a different method entirely—one that would turn the whole world purple.

Scientists from Cornell University analyzed how alien plants that rely on infrared radiation for photosynthesis might transform the hues of alien worlds. These kinds of bacteria, which include phototrophic anoxygenic bacteria and photoheterotrophic bacteria, could emit a distinctive “light fingerprint” that could be detectable by upcoming observatories, including the European Southern Observatory’s Extremely Large Telescope. The results of the study were published in the journal Monthly Notices of the Royal Astronomical Society.

“Purple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds,” Cornell University Ph.D. student Lígia Fonseca Coelho said in a press statement. “They already thrive here in certain niches… just imagine if they were not competing with green plants, algae and bacteria: A red sun could give them the most favorable conditions for photosynthesis.”

To understand the color and chemical signature such a world would emit, Coelho and her colleagues gathered 20 specimens of purple sulfur and purple non-sulfur bacteria from various places around the world—including hydrothermal vents and even ponds near Cornell’s campus. These bacteria rely on low-energy red and infrared right for a photosynthesis-like process, and while purple bacteria might be a biological niche today, some scientists theorize that an ancient Earth was likely much more purple than it is today.

A 2022 study from the University of Maryland explored why plants reflect the color green when technically the Sun emits the most light in the blue-green spectrum. The scientists argued that a light-sensitive molecule called retinal (which first appeared on Earth before chlorophyll) absorbed green light and reflect red and violet—which, to the human eye, would’ve looked purple.

When the molecule chlorophyll evolved on Earth—thanks in no small part to a rise in oxygen levels—the Sun’s green light was already being absorbed by retinal-leveraging plants. So, instead, the molecule absorbed all other available light. Even though the Sun emits less light in that spectrum, chlorophyll were part of a more advanced, efficient system at producing photosynthesis, and Earth’s green hue began to take shape.

But on oxygen-poor exoplanets orbiting cool, red dwarf stars, things might be drastically different. Coelho developed various models of Earth-like planets across a range of wet and dry environments, and many of the simulated “light fingerprints” came back purple.

“If purple bacteria are thriving on the surface of a frozen Earth, an ocean world, a snowball Earth or a modern Earth orbiting a cooler star,” Coelho said in a press statement. “We now have the tools to search for them.”

So, when aliens finally do reach Earth, don’t count on “little green men.” As for flying purple people-eaters... well, now we’re on to something.

[ghost2509]

An Astronomer Says He Knows Why Aliens Haven’t Contacted Us Yet

POPULAR MECHANICS
yahoo.com
Tim Newcomb
May 8, 2024

A lot of folks, even scientists, simply want to believe in advanced alien life. To cover the disappointment of not finding any, new theories keep cropping up as to just why we haven’t become BFFs with aliens. The latest comes from Frederick Walter, an astronomy professor from New York’s Stony Brook University. It features the idea that the universe has zapped the aliens.

In a theory Walter shared with the Daily Mail, he claims that gamma-ray bursts—a space eruption full of radiation that delivers the most energetic form of light in the universe that can be a million trillion times brighter than the sun—could have eliminated potential alien lifeforms.

“It’s a tightly focused beam,” he tells DailyMail.com, “and, if it’s directed through the plane of the galaxy, it could basically sterilize about 10 percent of the planets in the galaxy. It’s just one of many possible explanations.”

While admitting it falls in the category of a “morbid” explanation, the transparent power of a gamma-ray burst has the destructive ability to eliminate anything in its path.

The gamma-ray burst wasn’t even discovered until the 1960s when a satellite meant to search for nuclear activity from the Soviet Union detected this sharp radioactive burst. It was later determined the burst was of cosmic origin and the study of gamma-ray bursts began. NASA really began studying the phenomena heavily in 1991.

We don’t have a lot of history with gamma-ray bursts in the Milky Way, but that doesn’t mean the explosions aren’t happening throughout the universe. NASA research into the cosmic explosion found that the events occurred more frequently when old stars collapsed into black holes or when a new galaxy was forming and full of energy.

“It’s estimated that there is a gamma-ray burst every 100 million years or so, in any galaxy,” Walter says, although NASA research claims it could be as frequent as every 10,000 years. “Over a billion years, on average, you might expect a significant number of civilizations to be eradicated, should they exist.”

As researchers debate massive changes in Earth’s ancient history, the idea of a gamma-ray burst helping eliminate life on our planet is sometimes floated, too. For a gamma-ray burst to be effective in wiping out anything, it must hit that object. These events, with the short-term bursts considered less than 2 seconds and the long-term bursts going longer than 2 seconds, emit a somewhat pinpoint accuracy, akin to a lighthouse beam.

Still, anything within that powerful beam would completely vaporize, meaning if a gamma-ray burst was directed at a planet teeming with alien life, that alien life would no longer be teeming.

At the same time, scientist say the risk to humans from gamma-ray bursts is minuscule because of their very nature of scarcity and propensity for being far from the Milky Way.

Floating a gamma-ray burst as a theory to why aliens haven’t visited simply joins another long list of explanations, everything from the aliens showing no desire to explore beyond their own world to destroying themselves in the process. And while people debate the most plausible reason that aliens haven’t yet come knocking on Earth’s door, one theory often gets overlooked: just maybe super-intelligent alien lifeforms don’t exist. But if they once did, a gamma-ray burst could have eliminated them.

[ghost2509]

Hunting for ‘Dyson spheres’ across 1,000 galaxies to find alien life

msn.com
Story by Eric Ralls
May 15, 2024

The search for extraterrestrial intelligence is humanity's grand quest. While we have yet to detect alien signals, researchers are exploring innovative approaches to this cosmic mystery. Project Hephaistos, a recent Swedish initiative, offers a fresh perspective by looking for astroengineering signatures such as Dyson spheres.

Unending quest for alien life

For over 60 years, scientists have scoured the skies for signs of intelligent life. Despite finding over 2,000 exoplanets, we haven't detected any communication signals from alien civilizations. This raises the classic question: If intelligent life exists, why haven't we found it?

One possible answer is that advanced civilizations might be exceedingly rare, even if planets are common. If technologically advanced civilizations are rare, we might be alone in our galaxy. Therefore, our chances of finding them improve if we extend our search beyond the Milky Way.

Expanding our search to include other galaxies could increase the likelihood of detecting signs of intelligent life. This broader approach allows scientists to explore a much larger sample of potential habitats for advanced civilizations.

Project Hephaistos

Named after the Greek god of blacksmiths, Project Hephaistos seeks signatures of extraterrestrial technology rather than direct signals. Funded by the Magnus Bergvall foundation and Nordenskjöldska Swedenborgsfonden, this project is the first Swedish initiative in the search for extraterrestrial intelligence.

Instead of focusing on communication signals, Project Hephaistos aims to detect signs of alien technology. This approach involves looking for large-scale engineering projects, interstellar propulsion mechanisms, and industrial pollution in the atmospheres of exoplanets.

By identifying these technological signatures, scientists hope to find evidence of advanced civilizations without relying on direct communication signals.

Civilizations utilizing Dyson spheres

The first paper from Project Hephaistos investigates more than 1,000 galaxies similar to the Milky Way. The goal? To find Kardashev type III civilizations that have harnessed their galaxy's energy using technology like Dyson spheres.

Dyson spheres, proposed by physicist Freeman Dyson, are theoretical megastructures that could capture a star's energy. These structures would encompass a star, capturing a significant portion of its output and indicating a highly advanced civilization. By examining data from these galaxies, researchers aim to identify unusual energy patterns or other indicators of such massive constructs.

The search revealed no strong candidates for Kardashev type III civilizations. However, it set an upper limit of 0.3% on the fraction of local disk galaxies that could host such civilizations. This means that less than one in 300 galaxies similar to the Milky Way may contain advanced civilizations utilizing Dyson sphere technology.

While no definitive evidence was found, this result still opens new research avenues within mainstream astronomy. The study's methodology and findings provide a framework for future investigations and help refine the search criteria for detecting signs of advanced extraterrestrial civilizations.

Additionally, the project has uncovered several highly unusual galaxies that merit further study, potentially leading to new discoveries in astrophysics and the nature of galaxies.

Finding near-complete Dyson spheres

The second paper from Project Hephaistos focuses on detecting near-complete Dyson spheres using data from the Gaia space mission and the RAVE survey. Dyson spheres at this stage of completion would significantly dim the optical light from the stars they surround, creating noticeable discrepancies in distance measurements.

Gaia provides precise parallax measurements, which determine a star's distance by observing its apparent movement against distant background stars. RAVE, on the other hand, uses spectrophotometric distances, which estimate distance based on the star's brightness and spectrum.

By comparing these two distance measurements, researchers can identify stars with potential Dyson spheres, as a near-complete Dyson sphere would cause the star to appear dimmer than expected in optical wavelengths.

The researchers identified a handful of stars exhibiting the expected distance discrepancies indicative of near-complete Dyson spheres. These stars showed significant differences between their Gaia parallax distances and RAVE spectrophotometric distances, suggesting the presence of large structures dimming their light.

However, further observations suggested natural explanations for these discrepancies. One common issue is the presence of unseen companions, such as binary stars or planets, which can interfere with Gaia's measurements and create the illusion of a distance discrepancy.

For instance, the star TYC-6111-1162-1 initially appeared to be a good Dyson sphere candidate due to its discrepant distances. But follow-up observations showed temporal changes in its radial velocity, indicating the presence of an unseen companion. This companion likely caused Gaia to misinterpret its parallax measurements, ruling out TYC-6111-1162-1 as a Dyson sphere candidate.

Upper limits on partial Dyson spheres

The third paper from Project Hephaistos explores the possibility of finding partial Dyson spheres by analyzing large astronomical catalogs.

The researchers scanned data from the Gaia mission, which provides precise measurements of star positions and distances, and combined it with infrared surveys such as the Wide-field Infrared Survey Explorer (WISE) and the Two Micron All Sky Survey (2MASS). These infrared surveys detect thermal emissions from objects, which are crucial for identifying potential Dyson spheres.

A partial Dyson sphere would not completely obscure the star but would still produce significant amounts of waste heat detectable in the mid-infrared spectrum. Thus, the researchers looked for objects with low optical brightness combined with high mid-infrared fluxes, characteristics that could indicate the presence of a partial Dyson sphere.

Despite many interlopers, primarily young stellar objects (YSOs) that can exhibit similar characteristics, the study successfully set conservative upper limits on the fraction of Milky Way stars that could host Dyson spheres.

Young stellar objects often produce excess infrared emission due to surrounding dust and gas, which can mimic the signatures of Dyson spheres. However, by carefully analyzing and excluding these interlopers, the researchers could focus on more plausible candidates.

The results were significant: fewer than 1 in 50,000 stars within 100 parsecs of Earth could host Dyson spheres that are 90% complete and operating at an effective temperature of 300 K. This limit provides a benchmark for the prevalence of advanced civilizations in our galaxy and helps refine future searches for extraterrestrial technologies.

Future prospects of Dyson sphere research

Project Hephaistos's findings are promising. Two recent studies analyzed data from star-gazing satellites, developing methods to eliminate false positives in the search for Dyson spheres.

Ph.D. student Matías Suazo's team at Uppsala University developed a pipeline to identify potential Dyson spheres. Starting with five million objects, they narrowed it down to seven compelling candidates. This structure would emit waste heat in the form of mid-infrared radiation that, in addition to the level of completion of the structure, would depend on its effective temperature.

Similarly, the International School for Advanced Studies in Italy found 53 star candidates with excess mid-infrared measurements. While natural explanations like debris disks remain plausible, the possibility of Dyson spheres can't be ruled out yet.

The next steps

To confirm these findings, scientists need to take a closer look at the candidates, possibly with the James Webb Space Telescope. This powerful tool could provide the detailed data needed to distinguish between natural and artificial causes.

"It might be something that happens very rarely, like if two planets collide and produce an enormous amount of material," emphasized David Hogg, co-author of one study. Regardless of the outcomes, the search for Dyson spheres and technosignatures continues to inspire curiosity and drive scientific discovery.

[ghost2509]

Rocket company develops massive catapult to launch satellites into space without using jet fuel: '10,000 times the force of Earth's gravity'

TheCoolDown
yahoo.com
Rick Kazmer
June 15, 2024

http://youtu.be/csFyhYSLwichttp://

A California company has tech that will likely draw attention from the Punkin Chunkin community.

That's because SpinLaunch is developing a large rotating arm that uses kinetic energy to fling 440-pound satellites into low orbit, with successful tests already in the books. Importantly, the process doesn't need rocket fuel to work. It's all powered by electricity.

"This is not a rocket, and clearly our ability to perform in just 11 months this many tests and have them all function as planned, really is a testament to the nature of our technology," founder and CEO Jonathan Yaney said in a Space.com report from 2022, shortly after a 10th successful launch. The goal is to shoot constellations of satellites skyward — under 600 miles up — by 2026, per the report.

Satellites are used by scientists to monitor our planet's health from above, identifying polluting methane leaks, among other research. So a cleaner way to put them in the sky is exciting science.

Kinetic energy has been used by humans for centuries via trebuchets and siege machines during war, hurling heavy objects great distances. Pumpkin chucking, commonly called Punkin Chunkin, contests remain a popular way to teach kinetic and potential energy physics with similar human-made machines.

SpinLaunch's contraption will likely have some of the chuckers wondering how many pumpkins they could put in orbit, if given the chance.

The invention looks like a giant upright disc with a cylindrical barrel pointed upward. A 108-foot-long rotating arm spins at 5,000 miles per hour to achieve the best fling, Space.com and the company report. The vehicle travels at up to six times the speed of sound.

The company credits low-cost, high-strength modern carbon fiber and miniature electronics as key components behind the innovation.

"Modern electronics, materials, and simulation tools allow for satellites to be adapted to the kinetic launch environment with relative ease," the company states on its website. The technology must withstand a vacuum, in addition to very fast acceleration.

A video clip shared by the company shows the buildup as a test launch is about to happen at its New Mexico site. Experts are seen monitoring screens while others sit in control areas, akin to a NASA scene. When the craft exits the barrel, there's no exhaust to track it. If you blink, you will miss it entirely.

SpinLaunch was founded in 2014, and its leadership team has since raised tens of millions of dollars in funding. The company has been working with NASA, Airbus, and Cornell University, launching some of their equipment as part of testing. The tech has so far endured 10,000 Gs, "10,000 times the force of Earth's gravity," all per the Space.com report.

If SpinLaunch's concept proves reliable, it could eliminate the loads of fuel that is burned to launch spacecraft. In 2016, Business Insider noted that SpaceX's Falcon 9 rocket used more than 900,000 pounds of propellant for each liftoff, for reference. The fuel efficiency may have improved some since then.

CBC News reports that a growing number of launches are starting to draw scrutiny, particularly for ozone layer health. The barrier protects us from some of the sun's harmful radiation.

SpinLaunch can surpass the ozone layer without harming it. Next up for the company is creating a coastal orbital launch site geared to build upon its early success.

"It has proven that it's a system that is repeatedly reliable," Yaney said in the Space.com story.

[pepo-pepo]

Originally Posted by ghost2509

Rocket company develops massive catapult to launch satellites into space without using jet fuel: '10,000 times the force of Earth's gravity'....

pepo was expecting Wile E Coyote cutting the rope to shoot an Acme catapult!



.

[ghost2509]

Everything to Know About the Massive 'Planet Killer' Asteroid Passing Near Earth, Including How to Watch It Live

mensjournal.com
yahoo.com
Chris Malone Méndez
June 25, 2024

On June 27, a massive asteroid the likes of which are rarely seen on this side of the solar system will be making a very close approach to Earth. The event will providing a great opportunity for millions to learn about similar space rocks and what could happen in a potentially catastrophic asteroid collision.

How big is the asteroid?

2011 UL21 orbits the sun once every three years and is estimated to be somewhere between 1.1 and 2.4 miles wide, per SpaceReference. This makes it larger than 99 percent of known near-Earth asteroids according to the European Space Agency. It's been designated as a "potentially hazardous asteroid" due to its size.

"The term 'Potentially Hazardous Asteroid' (PHA) is a precise formal definition, referring to minor planets larger than approximately 140 meters that can come within 7.5 million kilometers from the Earth," Virtual Telescope Project scientific director Gianluca Masi said in a statement. “In other words, only the largest asteroids capable of approaching close enough to our planet are flagged as PHAs, which does not mean they are going to hit the Earth, but they nonetheless warrant a better monitoring."

How close will the 2011 UL21 asteroid come to Earth?

The space rock is expected to pass our planet at around 58,000 miles per hour. It will come within 4.1 million miles of Earth, according to NASA's Jet Propulsion Laboratory, thereby qualifying it as a potentially hazardous object. Still, it will be approximately 17 times farther away from Earth than the moon.

Is the 2011 UL21 asteroid the biggest to approach Earth?

2011 UL21 is big, but it pales in comparison to other space rocks that have had an impact on Earth history. It's likely at least 10 times smaller than the Vredefort asteroid, the largest space rock to ever hit Earth, and also around five times smaller than the space rock that wiped out the dinosaurs around 66 million years ago.

However, while any potential impact from 2011 UL21 would be less extreme than these historic collisions, the asteroid still has the potential to cause damage on a continental scale and eject enough debris into the atmosphere to trigger significant climatic changes, which is why it is considered a "planet killer."

Does the asteroid pose a threat?

While 2011 UL21 isn't projected to collide with Earth anytime soon, its sheer size is enough to permanently alter the course of planetary history if it did so. Asteroids of this size are sometimes referred to as "planet killers" for this reason, as the damage could reach across continents and release enough debris into the atmosphere to cause major environmental changes around the globe.

How can you watch the asteroid's approach live?

If you're interested in watching the approach, you can tune in to a free livestream from the Virtual Telescope Project that will show the view of the asteroid from the Bellatrix Astronomical Observatory in Ceccano, Italy. The stream begins June 27 at 4 p.m. ET and the close approach is expected to happen around 15 minutes later.

If you have a good telescope, you might even be able to see the asteroid just by looking up at night. It will be at its brightest on June 28 and 29 and visible across the Northern Hemisphere.

When will it approach Earth again?

2011 UL21 won't get this close to Earth again until 2089. At that time, the asteroid will get within 1.7 million miles of Earth, more than two and a half times closer than it will get this week.

[ghost2509]

China Finds Something Strange in Sample Retrieved From Moon

Futurism
yahoo.com
Victor Tangermann
June 27, 2024

Lunar Graphene

Chinese scientists have made an unusual discovery while analyzing the sample Chang'e-5 collected from the Moon's surface in December 2020.

They found naturally occurring "few-layer graphene" for the first time, as state-run news agency Global Times reports, which could have major implications for humankind's plans to make use of local resources once on the lunar surface.

The discovery could also offer new insights into the early geological evolution of the Moon. As the South China Morning Post reports, it may even upend a long-held theory that the Moon was formed after a small planet collided with the Earth and that much of its carbon came from this impact.

"The prevalent giant impact theory has been strongly supported by the notion of [a] carbon-depleted Moon derived from the early analysis of Apollo samples," the team led by researchers from Jilin University wrote in their paper published in the journal National Science Review, as quoted by the SCMP.

However, the findings suggest the existence of a "carbon-capture process on the Moon," leading to the "gradual accumulation of indigenous carbon" — a discovery that "may reinvent the understanding of chemical components... and the history of the Moon."

No Impact

Using a form of non-destructive chemical analysis called "Raman spectroscopy," the team confirmed the discovery of a type of few-layer graphene, which is graphene with anywhere between two and ten layers that can also be manufactured in a lab.

The researchers suggest the material may have formed as a result of solar wind battering the lunar surface and early volcanic eruptions.

The existence of pure "indigenous carbon" could challenge the long-held hypothesis that a small planet, roughly the size of Mars, collided with the Earth to form the Moon about 4.45 billion years ago.

However, the researchers admitted that meteorites may have still led to the formation of graphitic carbon on the Moon, as previous studies have suggested.

"Further in-depth property investigation of natural graphene would provide more information on the geologic evolution of the Moon," the team concluded.

[ghost2509]

Scientists have confirmed a cave on the moon that could be used to shelter future explorers

Associated Press
yahoo.com
MARCIA DUNN
July 15, 2024

CAPE CANAVERAL, Fla. (AP) — Scientists have confirmed a cave on the moon, not far from where Neil Armstrong and Buzz Aldrin landed 55 years ago, and suspect there are hundreds more that could house future astronauts.

An Italian-led team reported Monday that there's evidence for a sizable cave accessible from the deepest known pit on the moon. It's located at the Sea of Tranquility, just 250 miles (400 kilometers) from Apollo 11's landing site.

The pit, like the more than 200 others discovered up there, was created by the collapse of a lava tube.

Researchers analyzed radar measurements by NASA's Lunar Reconnaissance Orbiter, and compared the results with lava tubes on Earth. Their findings appeared in the journal Nature Astronomy.

The radar data reveals only the initial part of the underground cavity, according to the scientists. They estimate it’s at least 130 feet (40 meters) wide and tens of yards (meters) long, probably more.

“Lunar caves have remained a mystery for over 50 years. So it was exciting to be able to finally prove the existence" of one, Leonardo Carrer and Lorenzo Bruzzone of the University of Trento, wrote in an email.

Most of the pits seem to be located in the moon’s ancient lava plains, according to the scientists. There also could be some at the moon’s south pole, the planned location of NASA’s astronaut landings later this decade. Permanently shadowed craters there are believed to hold frozen water that could provide drinking water and rocket fuel.

During NASA’s Apollo program, 12 astronauts landed on the moon, beginning with Armstrong and Aldrin on July 20, 1969.

The findings suggest there could be hundreds of pits on the moon and thousands of lava tubes. Such places could serve as a natural shelter for astronauts, protecting them from cosmic rays and solar radiation as well as from micrometeorite strikes. Building habitats from scratch would be more time-consuming and challenging, even when factoring in the potential need of reinforcing the cave walls to prevent a collapse, the team said.

Rocks and other material inside these caves — unaltered by the harsh surface conditions over the eons — also can help scientists better understand how the moon evolved, especially involving its volcanic activity.

[ghost2509]

Scientists detect water sloshing on Mars. There could be a lot.

Mashable
yahoo.com
August 14, 2024

A pioneering NASA robot detected over a thousand quakes on Mars. It also may have revealed a huge reservoir of water.

Planetary scientists used unprecedented data collected by the space agency's InSight lander, which recorded geologic activity on Mars for four years, to reveal that water may exist many miles down in the Martian crust. The research, which invites further investigation, may explain where bounties of the Red Planet's water went as the world dried up, and suggests that Mars may host hospitable environs for life.

On our rocky planet, bounties of water exist in the subsurface. Why not on Mars, too?

"Exactly! We identified the Martian equivalent of deep groundwater on Earth," Michael Manga, a planetary scientist at UC Berkeley who coauthored the new research, told Mashable.

The study recently published in the journal Proceedings of the National Academy of Sciences.

The detected water is nowhere near the Martian surface — which is today 1,000 times drier than the driest desert on Earth. It exists some seven to 13 miles underground (11.5 to 20 kilometers) in cracks and ruptures in the deep Mars crust, as shown in the graphic below.

NASA designed the InSight lander to observe Mars' inner workings, so the craft carried a seismometer, similar to those that measure quakes on Earth. It picked up different types of seismic waves, caused by marsquakes, geologic activity, and meteorites bombarding the surface. Crucially, these waves, which are generated by an impulse like an impact or temblor, provide lots of information about the world below. The speed of a seismic wave depends on what the rock is made of, whether this rock has cracks, and what the cracks are filled with, Manga explained. The researchers then plug these seismic Martian readings (along with subsurface gravity measurements) into programs that simulate what lies below — they're the same computer models geologists use to map water aquifers on Earth or gas resources deep underground.

"A mid-crust whose rocks are cracked and filled with liquid water best explains both seismic and gravity data," Manga said.

A temperate Red Planet once hosted great Martian lakes and rivers. Some 3 billion years ago, scientists suspect much of this water was lost to space after Mars gradually lost its insulating atmosphere. Yet colossal amounts of water might have drained into the subsurface, too. It's unclear how much, though this latest water detection suggests a considerable amount of water could lie in the deep Martian crust.

"We knew that the liquid water being buried deep in the subsurface was one possible solution to the question of where Mars' ancient liquid surface water went," Manga said.

The possible existence of water raises an enticing question. Could something live down there? Our planet provides a clue.

"On Earth we find microbial life deep underground where rocks are saturated with water and there is an energy source," Manga said.

Future Martian explorers won't be able to drill many miles into Martian rock to access or analyze this water. But they might find other places, such as geologically active regions like Cerberus Fossae on Mars, where liquid water could potentially be expelled to the desert floor.

The Martian surface may indeed be a harsh, irradiated place, but it's plausible hardy life could thrive in the deep, watery underworld.

[ghost2509]

Food Tastes Mysteriously Bad in Space, And We May Finally Know Why

sciencealert
yahoo.com
Tom Hawking
August 21, 2024

Spending time in space has all sorts of effects on astronauts. Some perils of spaceflight are serious, others are best described as weird, and some fall in between, like the fact that food tastes bland and unappealing in space.

This curious phenomenon can be a serious enough problem that some astronauts struggle to receive sufficient nutrition, leading a team of food scientists from Australia and the Netherlands to look into potential causes.

Their recently published new study suggests that the explanation may lie in astronauts being isolated and uncomfortable, rather than being in orbit.

Previous research has suggested the issue might result from fluid shifts, an effect of weightlessness on how the body's internal fluids are distributed, causing facial swelling that recedes as the body acclimatizes to its new environment.

However, some astronauts have reported that their problems with food have persisted even after the effects of fluid shift have passed.

So food scientist Grace Loke from RMIT University in Australia and her colleagues focused on how a person's surroundings and mental state can affect their perception of aromas, which are highly influential on the perceived appeal of food.

The results suggest that at least some aromas are perceived differently in different environments – albeit not in the way that researchers expected.

"One of the long-term aims of the research is to make better-tailored foods for astronauts, as well as other people who are in isolated environments, to increase their nutritional intake closer to 100 percent," says senior author Julia Low, a sensory and eating behavior scientist at RMIT.

Given the obvious difficulty of actually sending their subjects to space, the team instead placed participants in a virtual reality environment designed to simulate the experience of being on the International Space Station (ISS).

This VR environment included floating objects to simulate microgravity, the team explains, along with "mounted space apparatus to evoke a sense of clutter and confinement" and background noise that "imitate[d] loud operational sounds that have been reported within the ISS".

While the idea that taste is subjective is certainly not new, the question of whether a VR environment can influence taste appears to be – Loke and her team note in their paper that, to their knowledge, "This is the first study to demonstrate individual variation in olfactory perception in VR".

To do this, the scientists provided participants with samples of three different odors: vanilla, almond, and lemon. They were asked to rate each scent's intensity on a scale of 1 to 5 – first in a normal room and then in the simulated ISS environment.

Fascinatingly, participants reported that while the lemon smell remained the same in both environments, the other two scents seemed more intense in the simulated ISS. The researchers suspect that benzaldehyde, a volatile aromatic compound found in both almonds and vanilla but not lemon, is the key factor in this.

And while the study doesn't necessarily provide answers about why astronauts' senses of taste and smell remain dulled after fluid shift abates, it does provide support for the hypothesis that perception of odor is contextual.

It also points at possible ways of mitigating the issue: as the authors write, "Perhaps certain volatile compounds sharing common odor profiles (i.e. sweet) are more likely to be contextually affected compared to others".

If this is the case, identifying compounds that retain their appeal in environments like the ISS – or even become more appealing – could inform the way astronauts' diets are designed.

There are potential uses for the findings back on Earth, too.

"This study could help personalize people's diets in socially isolated situations, including in nursing homes, and improve their nutritional intake," Low says.