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Author Topic: NEWS ON SPACE AND OUR PLANETARY SYSTEM  (Read 822550 times)
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Darja
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« Reply #2415 on: Sep 21, 2020, 02:55 AM »

Planets made of diamond may be hanging out in the cosmos

By Mike Wehner
ZME
9/21/2020

    Researchers theorize that, under the right conditions, carbon-rich exoplanets could generate huge quantities of diamonds beneath their surface.
    The recipe including heat, pressure, carbon, water, and time results in diamonds, and some planets are likely to have the right combination.
    These planets are most likely not habitable but may be worth visiting for the resources.

Earth has a lot of resources. The most valuable ones help to keep us alive and allowed life to exist on this planet in the first place, but some other resources like precious metals and gems are in relatively short supply. The cost of these resources reflects that scarcity, but the same may not be true on other worlds. In fact, some planets may be absolutely packed with resources that we consider rare.

A new study by researchers from Arizona State University and the University of Chicago has revealed that it’s possible for carbon-rich exoplanets to essentially become huge spheres of diamond floating through space.

As the researchers explain, the likelihood of a planet being something akin to a massive diamond is entirely based on the composition of the stars they orbit. Planets orbiting stars that are rich in carbon are more likely to be made of carbon themselves, mostly because the material that makes up a star is usually also responsible for forming the planets that eventually orbit it.

The other key to creating a “diamond exoplanet” is water. Water is abundant on Earth, but it’s also thought to be quite common in the cosmos as a whole. Water, carbon, and pressure — which the planets would have plenty of thanks to gravity — could result in interiors of these plants being packed with diamonds.

The researchers tested their theory by placing silicon carbide in a very high-pressure situation. They placed it in water and then compressed it with diamond “anvils” to boost the stress on the carbon, then heated it up using a laser to mimic the conditions inside a carbon-rich planet. The formula of heat, pressure, water, and carbon worked, and the result was diamonds and silica.

One big key that the researchers are quick to point out in their study published in The Planetary Science Journal is that these planets, while enticing, would definitely not be hospitable to life as we know it. The high carbon concentration would inhibit geological activity and, it’s thought, lead to an inhospitable atmosphere. Nevertheless, such planets could be targets for human exploration when it comes to resources.

“Regardless of habitability, this is one additional step in helping us understand and characterize our ever-increasing and improving observations of exoplanets,” Harrison Allen-Sutter, lead author of the study, said in a statement. “The more we learn, the better we’ll be able to interpret new data from upcoming future missions like the James Webb Space Telescope and the Nancy Grace Roman Space Telescope to understand the worlds beyond our own solar system.


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« Reply #2416 on: Sep 22, 2020, 03:03 AM »

Saturn’s icy moon is even more active than we thought

By Mike Wehner
BGR
9/22/2020

    A study of Enceladus images from the Cassini orbiter has revealed new clues as to the age of the ice on different parts of the moon.
    The moon’s south pole is covered in new ice, which is expected, but its northern hemisphere also has young ice, which was a surprise.
    Enceladus is one of the few places in our solar system where extraterrestrial life may exist in some form.

Of all the planets and moons in our solar system, Saturn’s icy moon Enceladus appears to be one of the few that may support life in some form. It has a solid shell of ice, but deep beneath the ice, there’s liquid water. We know this because we’ve seen it spewing out of massive fissures in the ice.

Now, researchers using data from the NASA Cassini space probe have detected what they believe is the signature of fresh ice not just at the active south pole of the moon, but also in the northern hemisphere, which is a new finding.

The research, which was published in the journal Icarus, uses infrared spectrometer data to estimate the age of the ice surrounding the moon. Fresh ice produces a different signature than old ice, and this data allows scientists to get a pretty good idea of when the ice formed.

The first discovery wasn’t a surprising one: Enceladus’s south pole is absolutely covered in fresh ice. NASA has spotted this happening, with huge plumes of liquid water spewing from cracks in the moon’s south pole. That water freezes almost instantly and much of it eventually settles back down onto the south polar region.

However, the Cassini spacecraft took images of all sides of the moon, and, as it turns out, there’s a good bit of fresh ice around the northern hemisphere as well. It’s not nearly as dense as the fresh ice near the south pole, but it’s an indication that the moon’s northern hemisphere was active in the not-so-distant past.

It’s impossible to say how the new ice got to the northern hemisphere based on the current observations. Either it enjoyed similar activity to the south pole, with cracks forming and freshwater spewing out, or it was a more gradual process, with water leaking out of smaller holes over time.

“The infrared shows us that the surface of the south pole is young, which is not a surprise because we knew about the jets that blast icy material there,” Gabriel Tobie, co-author of the research, said in a statement. “Now, thanks to these infrared eyes, you can go back in time and say that one large region in the northern hemisphere appears also young and was probably active not that long ago, in geologic timelines.”

As the search for life in our solar system continues to heat up, worlds like Enceladus, Europa, and Titan will get more and more attention. Understanding the mechanisms by which their surfaces work is going to be very important if we hope to grasp how life might form on one or all of them.


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« Reply #2417 on: Sep 23, 2020, 03:00 AM »

If there’s life on Venus, where did it come from?

By Mike Wehner
BGR
9/23/2020

    Researchers have examined various possibilities for how life may have arrived at Venus.
    Chemical signatures in the atmosphere suggest the possibility of life, but no confirmation has been made.
    One possibility is that Venus got its life from Earth.

In case you hadn’t heard, the biggest scientific news of the month is the discovery of what might be a biosignature of life on another planet. No, it’s Mars — though that would be really cool — It’s Venus, one of the most hostile places in our solar system. The discovery comes in the form of a chemical that is known to be produced by biological processes. It’s in the planet’s atmosphere in a higher concentration than should theoretically be possible without the presence of life. But if there is life on Venus, where is it? And how did it get there in the first place?

In a new essay published in The Conversation, researchers from Australia offer their own take on the discovery and engage in a bit of guessing as to how the planet may be hosting life if it actually is.

Venus is a toxic place, at least when it comes to life as we understand it. It’s incredibly hot and the pressure on the surface is crushing. Surface temperatures top 400 degrees Celsius, which is way too high for just about any organism on the surface of our planet. It’s not the kind of place that Earthly life would survive, much less thrive, but that doesn’t mean it can’t have some life of its own.

The researchers offer a few possibilities, including one that hedges on models that suggest Venus may have once been a bit more like Earth. The idea being that if life took root there, it could have evolved over time to be more adaptable, facing the harsh environment by evolving new traits and biological processes. It’s possible that the surface of Venus once had flowing water, which could have spawned microbial life. That microbial life — which may be capable of producing the chemical signatures seen today — may have “adapted to spread into the clouds,” according to the scientists.

One of the other possibilities is even more intriguing: that Venus got its life from Earth. The many theories about how life spread from one planet to another include the notion of panspermia, which is a fancy word for the idea that an impact from something like an asteroid could knock material loose from one planet and send it on a course for another. In this case, an impact on Earth could have sent microbial life on a trip to Venus, where it somehow adapted to life in the atmosphere.

It would be an incredible long shot, but then again, life, in general, might be a long shot, so anything seems possible.


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« Reply #2418 on: Sep 24, 2020, 03:17 AM »


“π Earth”: Astronomers discover Earth-sized planet that takes 3.14 days to orbit its star

Like clockwork, the planet moves around its star in Pi days.

Mihai Andrei
ZME
9/24/2020

Every new exoplanet discovery is remarkable in its own way, and if that planet happens to be Earth-sized, it’s even more special. If it’s connected to a famous constant (Pi), it’s basically an astronomy party.

Pi, the ratio of a circle’s circumference to its diameter, isn’t exactly 3.14. In fact, it’s 3.141592653589793238… and goes on forever. But for most people, 3.14 is a good enough approximation — and for the astronomers looking for this new planet, the similarity was too striking.

    “The planet moves like clockwork,” says Prajwal Niraula, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS), who is the lead author of a paper published today in the Astronomical Journal, titled: “π Earth: a 3.14-day Earth-sized Planet from K2’s Kitchen Served Warm by the SPECULOOS Team.”

    “Everyone needs a bit of fun these days,” says co-author Julien de Wit, of both the paper title and the discovery of the pi planet itself.

The planet is called K2-315b but already, astronomers have nicknamed it π Earth. It’s the 315th planetary system discovered with data from K2, the successor of the Kepler telescope — just one shy from another coincidence that would have made it number 314.

The first signs of the planet were reported in 2017, but it was only confirmed more recently. π Earth has approximately 95% of Earth’s mass, making it essentially Earth-sized, and orbits a star that’s 5 times smaller than the Sun.

However, there’s virtually no chance of life as we know it on the planet. For starters, the planet orbits very close to its star, and astronomers estimate that it heats up to around 450 Kelvin (177 degrees Celsius, or 350 degrees Fahrenheit). As mentioned, the planet also circles its star every 3.14 days — so a ‘year’ on the planet is little more than three days, which means it moves at a blistering speed of 81 kilometers per second, or about 181,000 miles per hour (compared to 30 km/s at the Earth’s equator).

However, the planet is interesting in itself, more than being a mathematical curiosity.

    “This would be too hot to be habitable in the common understanding of the phrase,” says Niraula, who adds that the excitement around this particular planet, aside from its associations with the mathematical constant pi, is that it may prove a promising candidate for studying the characteristics of its atmosphere.

    “We now know we can mine and extract planets from archival data, and hopefully there will be no planets left behind, especially these really important ones that have a high impact,” says de Wit, who is an assistant professor in EAPS, and a member of MIT’s Kavli Institute for Astrophysics and Space Research.

The researchers are also interested in a follow-up study on the Pi planet with the upcoming James Webb Space Telescope (JWST), to see potential details of the planet’s atmosphere. For now, they are combing through other telescope datasets for signs of Earth-like planets — Pi or non-Pi.

The study has been published in the Astronomical Journal.


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« Reply #2419 on: Sep 25, 2020, 03:24 AM »

If you’re looking for extraterrestrial life, these four planets may have it

By Mike Wehner
BGR
9/25/2020

    Space science researcher Gareth Dorrian runs down his top four worlds with the possibility of hosting life.
    Planets like Mars and icy moons like Europa could hold life in some form, though we don’t know yet what form they could take.
    Missions to most of these worlds are already either happening or are planned for the future.

It wasn’t long ago that most science fans had written off the possibility of finding life in our solar system. At the time it was already clear that Mars was a dusty, dry hellscape and that no other planet or Moon offered Earth-like conditions. In recent years, however, scientists have realized that extraterrestrial life may indeed exist within our system, we just have to know where to look.

Now, space science researcher Gareth Dorrian offers a rundown of the planets and other heavenly bodies that offer us the best odds of finding life within our own stellar neighborhood, and some of them may surprise you.

Dorrian’s first target is Mars, which is fairly predictable. Mars is indeed the most Earth-like planet in our system. It’s rocky and has at least a little bit of ice, and we know that it was once covered in liquid water to a large extent. Over billions of years, that all changed, but what was the planet like back then? Was it just water and rock, or did life thrive there?

Whatever the planet’s history, there’s a possibility that life in some form still exists on Mars. Subsurface lakes have been detected, and the planet has a habit of spewing methane clouds that wax and wane with the seasons, which could be a hint that life is still hiding out somewhere. It wouldn’t be the traditional “Martians” of science fiction, and would likely be microbial in nature, but even that would be a huge discovery.

Then comes the ice moons of Saturn and Jupiter: Enceladus and Europa. Both are covered in a thick layer of ice that, for a long time, was thought to be the extent of what the planet had to offer. However, upon closer inspection, it’s become clear that liquid water is abundant beneath the frosty shell. Tidal forces keep the water in a liquid state, and heat from deep within the planet may also be playing a role. If that’s true, life could exist there, even in the absence of sunlight.

The last world on Dorrian’s list is a bit of a shocker: Saturn’s largest moon, Titan. Titan is definitely an interesting place, but as far as life is concerned, it seems like a long shot. The moon has liquid lakes and rivers on its surface, but it’s not water that flows through them, it’s hydrocarbons like liquid methane and ethane chilled to very low temperatures. However, if the planet has liquid water deep down beneath its toxic surface, there’s a possibility that life exists there.


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« Reply #2420 on: Sep 26, 2020, 03:45 AM »


Back to Venus: Upstart company wants to beat NASA in search for life

on September 26, 2020
By Agence France-Presse

Can a small American aerospace company get to Venus before NASA returns to our superheated planetary neighbor?

That’s what Peter Beck, the CEO of Rocket Lab, is hoping as he sets his sights on launching a low-cost probe in 2023.

Over the past decade his company has become very good at putting satellites in to orbit — and his dream of taking the next step, an interplanetary mission, has received a shot of adrenaline recently with the surprising discovery of a gas linked to living organisms in Venus’s corrosive, sulfuric atmosphere.

“What we’re looking for on Mars is signs of previous life,” Beck explains.

“Whereas Venus, it’s signs of potential life now.”

With its hellish landscape, Venus has been largely neglected by the major space agencies since the 1980s in favor of the Solar System’s more distant bodies.

Dozens of missions have notably been sent to Mars seeking signs of ancient microbes.

But the discovery by Earth-based radio telescopes of a gas called phosphine in Venus’ atmosphere, reported on September 14, sparked a new wave of enthusiasm among scientists who had for years defended the hypothesis that tiny organisms could live in the planet’s clouds.

Phosphine isn’t definitive proof of life. But it is possible its presence is linked to living organisms, as it is on our planet.

The finding led NASA to declare it was time to once more prioritize Venus.

Beck, however, has always been in the pro-Venus camp, and for two years has been contemplating sending an entirely privately-funded probe there, he said.

He calculated, with the help of a PhD student, that a small satellite called “Photon” that Rocket Lab developed in-house could be adapted into a spacecraft for an interplanetary voyage.

Such bids have historically been the domain of national space agencies, given the enormous costs involved — but Beck thinks he has developed a budget solution.

“I would expect a mission to Venus to be sort of $30 million,” he told AFP by video from Auckland, New Zealand.

“When you can measure interplanetary missions in tens of millions of dollars instead of billions, and months instead of decades, the opportunity for discovery is just incredible,” he said.

– Free-falling –

Rocket Lab’s specialty is sending small satellites into Earth orbit with its small 18-meter high rocket — a highly lucrative market in recent years as demand for microsatellites has exploded.

The company’s Venus probe will be very small, weighing around 80 pounds (37 kilograms) and just a foot (30 centimeters) in diameter.

The trip from Earth will take 160 days, then Photon will launch the probe into Venus’ clouds, where it will take readings as it falls, without a parachute, at almost 25,000 miles per hour (11 kilometers per second).

The probe will have between just 270 and 300 seconds to analyze an atmosphere that is almost a hundred times denser than Earth’s before it disintegrates or crashes on the planet’s fiery surface, where temperatures are hot enough to melt lead (900 degrees Fahrenheit, or 480 degrees Celsius).

The hardest part is deciding on the scientific instrument: what molecules should it look for?

Miniaturization is another problem. The probe will need to weigh seven pounds (three kilograms), which some experts doubt is possible, but Beck disagrees.

Rocket Lab will need help from leading scientists, and has already recruited MIT astronomer and planetary scientist Sara Seager.

The adventure is the latest chapter in a new era of space exploration fuelled not by governments but by individual curiosity and ambition, one that so far has been best symbolized by Elon Musk, the iconoclastic founder of SpaceX.

SpaceX revolutionized the sector through its reusable rockets that have now sent astronauts to the International Space Station, and has its sights set on colonizing Mars.

NASA is no longer afraid to subcontract missions to privateers, and Rocket Lab will be paid $10 million to send a microsatellite into lunar orbit in 2021.

As for Venus, Beck would like to offer his services to NASA.

The space agency is considering returning to Venus, but not until 2026 at the earliest. Its last Venus orbiter was Magellan, which arrived in 1990, but other vessels have made fly-bys since then.

“We want to do many, many missions a year,” said the young CEO.

© 2020 AFP


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« Reply #2421 on: Sep 28, 2020, 02:39 AM »


US probe to touch down on asteroid Bennu on October 20

on September 28, 2020
By Agence France-Presse

After a four-year journey, NASA’s robotic spacecraft OSIRIS-REx will descend to asteroid Bennu’s boulder-strewn surface on October 20, touching down for a few seconds to collect rock and dust samples, the agency said Thursday.

Scientists hope the mission will help deepen our understanding of how planets formed and life began and provide insight on asteroids that could impact Earth.

“Years of planning and hard work by this team are essentially coming down to putting the TAGSAM (Touch-And-Go Sample Acquisition Mechanism) into contact with the surface for just five to 10 seconds,” said Mike Moreau, OSIRIS-REx deputy project manager.

NASA has chosen a site called Nightingale, a rocky area 52 feet (16 meters) in diameter, for the spacecraft’s robotic arm to attempt to collect a sample, because it holds the greatest amount of unobstructed fine-grained material.

The spacecraft, about the size of a large van, will need to touch down in an area about the size of a few parking spots, taking care to avoid surrounding boulders.

Because the spacecraft and Bennu will be approximately 207 million miles (334 million kilometers) from Earth, it will take about 18.5 minutes for signals to travel between them.

This prevents the live commanding of flight activities, so the spacecraft will need to perform the sequence autonomously.

OSIRIS-REx is supposed to collect at least 2 ounces (57 grams) of Bennu’s rocky material to bring back to Earth –- the largest sample return from space since the Apollo program.

It will deliver its payload to Earth on September 24, 2023.


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« Reply #2422 on: Sep 29, 2020, 03:19 AM »


Infrared mosaic reveals hot geology on cold moon

Saturn's moon Enceladus features ice tectonics and subsurface liquid water.

Mihai Andrei
ZME
9/29/2020

Enceladus may look like a frozen snowball to the naked eye, but researchers have known for a while that there’s more to this small moon than meets the eye.

For starters, Enceladus shoots out enormous plumes of ice and vapor into space, suggesting a warm liquid ocean under the icy crust. Now, with data from the Cassini spacecraft, researchers have published an infrared mosaic highlighting Enceladus’ active geology.

In these detailed infrared images of Saturn’s icy moon Enceladus, reddish areas indicate fresh ice that has been deposited on the surface. Credit: NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute: 1st image below

New Ice

It was in 2005 that astronomers analyzed detailed images coming from Enceladus. Far from being a boring old moon, Enceladus turned out to be remarkably active in more than one way.

The first thing researchers noticed is that Enceladus features several so-called “tiger stripes”: large fractures in its icy surface. While interesting, the fractures themselves are not enough to indicate an active geology on the satellite. But when they looked at spectral data, researchers noticed another weird thing: these areas have elevated surface temperatures. They’re hotter (or rather, less cold) than the surrounding area.

The final puzzle piece came when the Cassini spacecraft found evidence of massive volcanic eruptions coming from Enceladus — erupting not with lava, as here on Earth, but rather with water. This type of cold volcanism (called cryovolcanism) strongly suggested that Enceladus has an internal source of heat and is active geologically and tectonically. Since no impact craters have been found in or around these tiger stripes, it can also be inferred that the surface of the satellite is relatively new — another indication of active geology.

The new spectral map highlights the youngest ice, showing that this clearly correlates with tiger stripes. In other words, the infrared map is a smoking gun that the tiger stripes are areas where new ice flows to the surface of Enceladus from an interior ocean, like lava flows here on Earth.

But while the tiger stripes are visible in the south pole area, some of the infrared features also appear in the northern hemisphere, suggesting that the same geological processes happen in both hemispheres. Researchers also speculate the existence of seafloor hotspots driving the moon’s geology.

    “The infrared shows us that the surface of the south pole is young, which is not a surprise because we knew about the jets that blast icy material there,” said Gabriel Tobie, co-author of the new research.

    “Now, thanks to these infrared eyes, you can go back in time and say that one large region in the northern hemisphere appears also young and was probably active not that long ago, in geologic timelines.”

The infrared images have been incorporated in an interactive globe which you can explore here.

The study has been published in the journal Icarus.

The surface of Enceladus is riddled with cracks and fractures. Image credits: NASA/JPL.: 2nd image


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« Reply #2423 on: Sep 30, 2020, 03:12 AM »

There may be way more water on Mars than we realized

By Mike Wehner
BGR
9/30/2020

    Researchers think they’ve spotted signatures of liquid water hiding out beneath the surface of Mars.
    The south pole in particular is apparently a hot spot for subglacial lakes, according to data from the Mars Express spacecraft.
    Future missions could investigate the claims and provide proof.

Just exactly how much liquid water is on Mars? If you asked that question 40 years ago the answer you got from some scientists may have been “none,” but things have changed a lot since then. More advanced technology and a slew of new research efforts have revealed that there may indeed be water beneath the surface of Mars and, depending on the season, even a bit on the surface itself.

Now, a team of scientists has published a paper in Nature Astronomy suggesting that not only does Mars have a whole bunch of liquid water, but it’s also actually hiding beneath the surface of the planet.

The Mars Express probe has been orbiting Mars for well over a decade now. One of the instruments it has at its disposal is called MARSIS, which is short for Mars Advanced Radar for Subsurface and ionosphere Sounding. That’s a fancy way of saying that it can look inside of things that a simple imaging camera could not, and when it peers at the Martian poles it can see ice and, apparently, water hiding out there.

“The detection of liquid water by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) at the base of the south polar layered deposits in Ultimi Scopuli has reinvigorated the debate about the origin and stability of liquid water under present-day Martian conditions,” the researchers write. “Our results strengthen the claim of the detection of a liquid water body at Ultimi Scopuli and indicate the presence of other wet areas nearby. We suggest that the waters are hypersaline perchlorate brines, known to form at Martian polar regions and thought to survive for an extended period of time on a geological scale at below-eutectic temperatures.”

The water, described by the researchers as brine, would have to be incredibly salty to maintain its liquid state in the frigid conditions of the Martian pole. Even if it were in liquid form, it would be a stretch to imagine life persisting in sub-freezing, salty syrup beneath the surface. A stretch… but not impossible.

In any case, the readings from MARSIS appear to show subsurface lakes, but that’s only one data point, and it’s data from a machine that was launched nearly two decades ago. It’s going to take a bit more for the scientific community to jump on board with this theory, though if it could in some way be proven, it would make the pole a very interesting location for future exploration, either by robots or humans.


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« Reply #2424 on: Oct 01, 2020, 02:50 AM »

Life on Venus? Jupiter may have made Venus inhabitable

By Mike Wehner
BGR
10/1/2020

    New research suggests that Venus was once potentially habitable, but that likely changed when Jupiter swooped in and messed things up.
    Venus once had a much more elliptical orbit, allowing its surface to cool off for extended periods of time.
    When Jupiter pushed up closer to the Sun, it may have changed the orbit of Venus and caused it to remain scorching hot all the time.

There’s been a lot of Venus in the news lately and for very good reason. Possible biosignatures were detected in the planet’s atmosphere, hinting at the slim chance that life in some form exists on or above the planet’s surface. But while we ponder what kind of life may exist there, researchers say that the planet probably had a good chance of being habitable if it weren’t for Jupiter’s influence.

In a new study published in the Planetary Science Journal, scientists from UC Riverside in California reveal that Jupiter likely played a big role in the current conditions we see on Venus. Had Jupiter not been involved, the planet might have ended up in a much more favorable location in our solar system.

Using computer models, the researchers suggest that Jupiter’s movement during its very early formative period likely affected Venus in a dramatic way. Jupiter pushed up closer to the Sun and then backed away to roughly where it is today, over the course of many millions of years.

When that happened, its gravity influenced Venus in such a way that it pushed the planet into a nearly perfectly circular orbit around the Sun. That wasn’t always the case, however, and it’s likely that when Jupiter was closer to the Sun, Venus had a much more elliptical orbit, allowing it to escape the intense heat of the star for extended periods of time and, possibly, remain habitable for an untold period of time.

“One of the interesting things about the Venus of today is that its orbit is almost perfectly circular,” Stephen Kane, lead author of the study, said in a statement. “With this project, I wanted to explore whether the orbit has always been circular and if not, what are the implications of that?”

“As Jupiter migrated, Venus would have gone through dramatic changes in climate, heating up then cooling off and increasingly losing its water into the atmosphere,” Kane explains. It was during this rough period that Venus began to gradually turn into the hostile “hellscape” it is today.

As for the notion that Venus has life in some form on or around it, Kane isn’t convinced. Hedging bets on the presence of phosphine gas to indicate life could backfire, as there are non-biological processes that can also create it. “There are probably a lot of other processes that could produce the gas that haven’t yet been explored,” Kane notes.


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« Reply #2425 on: Oct 02, 2020, 03:27 AM »

Giant black hole discovered at centre of cosmic ‘spider’s web’

on October 2, 2020
By Agence France-Presse

Astronomers have discovered six galaxies ensnared in the cosmic “spider’s web” of a supermassive black hole soon after the Big Bang, according to research published Thursday that could help explain the development of these enigmatic monsters.

Black holes that emerged early in the history of the Universe are thought to have formed from the collapse of the first stars, but astronomers have puzzled over how they expanded into giants.

The newly discovered black hole — which dates from when the Universe was not even a billion years old — weighs in at one billion times the mass of our Sun and was spotted by the European Southern Observatory (ESO).

Scientists said the finding helps provide an explanation for how supermassive black holes such as the one at the centre of our Milky Way may have developed.

This is because astronomers believe the filaments trapping the cluster of galaxies are carrying enough gas to “feed” the black hole, enabling it to grow.

“The cosmic web filaments are like spider’s web threads,” said Marco Mignoli, an astronomer at the National Institute for Astrophysics (INAF) in Bologna who led the research, which was published in the journal Astronomy & Astrophysics.

“The galaxies stand and grow where the filaments cross, and streams of gas — available to fuel both the galaxies and the central supermassive black hole — can flow along the filaments.”

Mignoli said that until now there had been “no good explanation” for the existence of such huge early black holes.

– ‘Tip of the iceberg’ –

Researchers said the web structure may have formed with the help of dark matter — thought to attract huge amounts of gas in the early Universe.

“Our finding lends support to the idea that the most distant and massive black holes form and grow within massive dark matter halos in large-scale structures, and that the absence of earlier detections of such structures was likely due to observational limitations,” said co-author Colin Norman of Johns Hopkins University.

The entire web is over 300 times the size of the Milky Way, according to a statement from ESO.

But it said the galaxies are also some of the faintest that current telescopes can spot, adding the discovery was only possible using the largest optical telescopes available, including ESO’s Very Large Telescope in Chile’s Atacama Desert.

“We believe we have just seen the tip of the iceberg, and that the few galaxies discovered so far around this supermassive black hole are only the brightest ones,” said co-author Barbara Balmaverde, an astronomer at INAF in Torino, Italy.

The research is the latest to try and illuminate the mysterious formation of these cosmic monsters, which are so dense that not even light can escape their gravitational pull.

In September, two consortiums of some 1,500 scientists reported the discovery of GW190521, formed by the collision of two smaller black holes.

What scientists observed were gravitational waves produced more than seven billion years ago when they smashed together, releasing eight solar masses worth of energy and creating one of the most powerful events in the Universe since the Big Bang.

At 142 solar masses, GW190521 was the first “intermediate mass” black hole ever observed.

Scientists said the finding challenges current theories on the formation of supermassive black holes, suggesting it could be through the repeated merger of these mid-sized bodies.

© 2020 AFP


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« Reply #2426 on: Oct 03, 2020, 03:03 AM »


What’s the matter with the Universe? Scientists have the answer

By Agence France-Presse
10/3/2020

A team of US astrophysicists has produced one of the most precise measurements ever made of the total amount of matter in the Universe, a longtime mystery of the cosmos.

The answer, published in The Astrophysical Journal on Monday, is that matter consists of 31.5 percent — give or take 1.3 percent — of the total amount of matter and energy that make up the Universe.

The remaining 68.5 percent is dark energy, a mysterious force that is causing the expansion of the Universe to accelerate over time, and was first inferred by observations of distant supernovae in the late 1990s.

Put another way, this means the total amount of matter in the observable Universe is equivalent to 66 billion trillion times the mass of our Sun, Mohamed Abdullah, a University of California, Riverside astrophysicist and the paper’s lead author told AFP.

Most of this matter — 80 percent — is called dark matter. Its nature is not yet known but it may consist of some as-yet-undiscovered subatomic particle.

The latest measurements correspond well with values previously found by other teams using different cosmological techniques, such as by measuring temperature fluctuations in the low-energy radiation left over from the Big Bang.

“This has been a long process over the course of 100 years where we’re gradually getting more and more precise,” Gillian Wilson, the study’s co-author and a professor at UCR told AFP.

“It’s just kind of cool to be able to make such a fundamental measurement about the Universe without leaving planet Earth,” she added.

So how exactly do you weigh the Universe?

The team honed a 90-year-old technique that involves observing how galaxies orbit inside galaxy clusters — massive systems that contain thousands of galaxies.

These observations told them how strong each galaxy cluster’s gravitational pull was, from which its total mass could then be calculated.

– Fate of the Universe –

In fact, explained Wilson, their technique was originally developed by the pioneering astronomer Fritz Zwicky, who was the first person to suspect the existence of dark matter in galaxy clusters, in the 1930s.

He noticed that the combined gravitational mass of the galaxies he observed in the nearby Coma galaxy cluster was insufficient to prevent those galaxies from flying away from one another, and realized there must be some other invisible matter at play.

The UCR team refined Zwicky’s technique, developing a tool they called GalWeight that determines more accurately which galaxies belong to a given cluster and which do not.

They applied their tool to the Sloan Digital Sky Survey, the most detailed three-dimensional maps of the Universe currently available, measuring the mass of 1,800 galaxy clusters and creating a catalog.

Finally, they compared the number of clusters observed per unit volume in their catalog against a series of computer simulations, each of which was fed a different value for the total matter of the Universe.

Simulations with too little matter had too few clusters, while those with too much matter had too many clusters.

The “Goldilocks” value they found fit the simulations just right.

Wilson explained that having a more precise measure of the total amount of matter of the Universe may take us a step closer to learning the nature of dark matter, because “we know just how much matter we should be looking for” when scientists carry out particle experiments, for example at the Large Hadron Collider.

What’s more, “the total amount of dark matter and dark energy tells us the fate of the Universe,” she added, with the current scientific consensus being that we are headed for a “Big Freeze” where galaxies move further and further apart, and the stars in those galaxies eventually run out of fuel.

© 2020 AFP


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« Reply #2427 on: Oct 05, 2020, 02:37 AM »

Signs of life on Venus may have been found decades ago

By Mike Wehner
BGR
10/5/2020

    NASA found the clues to life on Venus almost four decades ago but never realized it.
    A probe that was sent to Venus back in 1978 returned readings that showed the presence of what appears to be phosphine, which may be produced by biological processes.
    The data supports the recent research that found phosphine in Venus’ atmosphere, though we still don’t know if life actually exists there.

There’s been a whole lot of talk recently about the possibility of life existing in some form on Venus. The planet is a toxic hellscape, but upon scanning its atmosphere a compound called phosphine was detected, which can originate from organic processes. It’s big news, and space agencies are already talking about how they might further probe the mystery with missions to Venus, but is this really news? Shockingly, it might not be.

As LiveScience reports, a now-ancient NASA mission to Venus way back in 1978 may have detected the presence of phosphine decades before this more recent discovery. The data is examined in a new paper that was published to arXiv.

When the news began to circulate that phosphine was discovered in the atmosphere of Venus, researchers began to wonder if a similar signature might be lurking in data collected by the Pioneer 13 mission which included a probe that cruised down to the planet’s surface while collecting data about its atmosphere and other conditions.

The probe was supported by a parachute, giving it time to collect samples and analyze them, beaming the data back to Earth as rapidly as possible. At the time, the researchers didn’t mention anything about phosphine or other phosphorus-based compounds, but the data was still available to be studied, and that’s exactly what a team of researchers did.

So, what did they find? Well, the data shows the presence of phosphorous compounds, and based on the readings and a little bit of math, it seems likely that the data indicates the presence of phosphine.

“We were inspired to re-examine data obtained from the Pioneer-Venus Large Probe Neutral Mass Spectrometer (LNMS) to search for evidence of phosphorus compounds,” the researchers write. “The LNMS obtained masses of neutral gases (and their fragments) at different altitudes within Venus’ clouds. Published mass spectral data correspond to gases at altitudes of 50-60 km, or within the lower and middle clouds of Venus – which has been identified as a potential habitable zone. We find that LMNS data support the presence of phosphine; although, the origins of phosphine remain unknown.”

So, yeah, NASA’s probe detected what is likely phosphine nearly four decades ago and never realized it. That’s pretty wild, and it kind of makes you wonder what other discoveries have been unknowingly made over the decades that NASA and other space agencies have been conducting missions in space.


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« Reply #2428 on: Oct 06, 2020, 03:14 AM »

Salty ponds may be under Mars' icy surface, raising prospect of Martian life

Italian scientists provide further evidence of underground lake and smaller bodies of water in study

Associated Press in Cape Canaveral
10/6/2020

A network of salty ponds may be gurgling beneath Mars’ south pole alongside a large underground lake, raising the prospect of tiny, swimming Martian life.

Italian scientists reported their findings Monday, two years after identifying what they believed to be a large buried lake. They widened their coverage area by a couple hundred miles, using even more data from a radar sounder on the European Space Agency’s Mars Express orbiter.

In the latest study appearing in the journal Nature Astronomy, the scientists provide further evidence of this salty underground lake, estimated to be 12 miles to 18 miles (20km to 30km) across and buried 1 mile (1.5km) beneath the icy surface.

Even more tantalizing, they’ve also identified three smaller bodies of water surrounding the lake. These ponds appear to be of various sizes and are separate from the main lake.

Roughly 4bn years ago, Mars was warm and wet, like Earth. But the red planet eventually morphed into the barren, dry world it remains today.

The research team led by Roma Tre University’s Sebastian Emanuel Lauro used a method similar to what’s been used on Earth to detect buried lakes in the Antarctic and Canadian Arctic. They based their findings on more than 100 radar observations by Mars Express from 2010 to 2019; the spacecraft was launched in 2003.

All this potential water raises the possibility of microbial life on – or inside – Mars. High concentrations of salt are likely keeping the water from freezing at this frigid location, the scientists noted. The surface temperature at the south pole is an estimated minus 172F (minus 113C), and gets gradually warmer with depth.

These bodies of water are potentially interesting biologically and “future missions to Mars should target this region”, the researchers wrote.


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« Reply #2429 on: Oct 07, 2020, 02:56 AM »


Are aliens hiding in plain sight?

Several missions this year are seeking out life on the red planet. But would we recognise extraterrestrials if we found them?

Philip Ball
Guardian
7 Sep 2020 17.00 BST

In July, three unmanned missions blasted off to Mars – from China (Tianwen-1), the US (Nasa’s Mars 2020 Perseverance Rover) and the United Arab Emirates (Hope). The Chinese and American missions have lander craft that will seek signs of current or past life on Mars. Nasa is also planning to send its Europa Clipper probe to survey Jupiter’s moon Europa, and the robotic lander Dragonfly to Saturn’s moon Titan. Both moons are widely thought to be promising hunting grounds for life in our solar system – as are the underground oceans of Saturn’s icy moon Enceladus.

Meanwhile, we can now glimpse the chemical makeup of atmospheres of planets that orbit other stars (exoplanets), of which more than 4,000 are now known. Some hope these studies might disclose possible signatures of life.

But can any of these searches do their job properly unless we have a clear idea of what “life” is? Nasa’s unofficial working definition is “a self-sustaining chemical system capable of Darwinian evolution”. “Nasa needs a definition of life so it knows how to build detectors and what kinds of instruments to use on its missions,” says zoologist Arik Kershenbaum of the University of Cambridge. But not everyone thinks it is using the right one.

Astrobiologist Lynn Rothschild of Nasa’s Ames research centre in California sees a cautionary tale in AA Milne’s story from Winnie-the-Pooh, in which Pooh and Piglet hunt a Woozle without knowing what it looks like and mistake their own footprints for its tracks. “You can’t hunt for something if you have no idea what it is,” she says.

The problem of defining life has haunted planetary scientists ever since Nasa’s two Viking landers touched down on Mars in 1976. Since then, rovers have travelled dozens of miles over the Martian plains but found no hint of life. Would we know it if we saw it, though?

Some astrobiologists – scientists who study the possibility of life on other worlds – think our view is too parochial. We only know of one kind of life: the terrestrial sort. All living things on Earth are made from cells adapted to a watery environment, using molecular machinery built from proteins and encoded as genes in DNA. Few scientists think that extraterrestrial life – if it exists at all – would rely on the same chemicals. “It would be wrong to assume that our familiar biochemistry is what we’re going to find on other planets,” says Kershenbaum. Titan’s surface, for example, is too cold (minus 179C) for liquid water, but the Huygens lander mission of 2005 revealed lakes of another kind, made from hydrocarbons like those in petrol, mainly methane and ethane.

Rothschild thinks the universal rules of chemistry narrow some of the options. “I have difficulty imagining another life form that is not based on carbon,” she says. So it makes sense to design life-seeking planetary missions with that in mind. Water too “has a ton of advantages” as life’s solvent. Even if there were interesting chemical reactions happening in the methane lakes of Titan, they would be slowed down greatly by the frigid temperatures. Could life proceed at such a glacial pace? Planetary scientist Stuart Bartlett of the California Institute of Technology in Pasadena is keeping an open mind. “There could be organisms floating in Titan’s atmosphere that essentially drink petrol to sustain themselves,” he says.

It has long been thought that any entities that warrant being called alive share attributes that don’t depend on their precise chemical composition. It’s frustratingly difficult, however, to say just what those general qualities are. Living systems – even bacteria – are extremely complex, maintained by information that passes (in our case via genes) between generations and creates organisation. But that’s not the cold, dead order of crystals, where atoms are stacked in regular patterns. It’s more like the dynamic order of a city or a cloud formation, which scientists say is “out of equilibrium”: it is constantly fed with energy and doesn’t settle into a static state.

    Bartlett and Wong propose a broader category called "lyfe", of which life as we know it is just one variation

When James Lovelock, now known for the Gaia hypothesis that proposes our entire planet is akin to a living entity, was involved in designing the Viking landers in the 1970s, he suggested looking for such chemical disequilibrium in the environment – which perhaps only life could sustain over geological timescales. But states of “ordered disequilibrium” can also be found in non-living systems, such as flowing liquids, so this criterion alone doesn’t single out life.

Bartlett, working with astrobiologist Michael Wong of the University of Washington in Seattle, argues that we need to escape the straitjacket of Earth-based thinking about life. They propose introducing a broader category called “lyfe” (pronounced, in an oddly West Country fashion, as “loif”), of which life as we know it is just one variation. “Our proposal attempts to break free of some of the potential prejudices due to us being part of this one instantiation of lyfe,” says Bartlett.

They suggest four criteria for lyfe:

1. It draws on energy sources in its environment that keep it from becoming uniform and unchanging.

2. It grows exponentially (for example by replication).

3. It can regulate itself to stay stable in a changing environment.

4. It learns and remembers information about that environment. Darwinian evolution is an example of such learning over very long timescales: genes preserve useful adaptations to particular circumstances.

The two researchers say there are “sublyfe” systems that only meet some of these criteria, and also perhaps “superlyfe” that meets additional ones: lyfe forms that have capabilities beyond ours and that might look on us as we do on complex but non-living processes such as crystal growth.
Perseverance: the new mission to Mars

“Our hope is that this definition frees our imaginations enough to not miss lyfe that might be hiding in plain sight,” says Bartlett. He and Wong suggest that some lyving organisms might use energy sources untapped here on Earth, such as magnetic fields or kinetic energy, the energy of motion. “There is no known life form that directly harnesses kinetic energy into its metabolism,” says Bartlett.

They say there might be other ways of storing information than in genetic strands like DNA. Scientists have, for example, already devised artificial ways to store and process information using two-dimensional arrays of synthetic molecules, like checkerboard arrays or abacuses. Bartlett says that the distinction between lyfe and non-lyfe might be hazy: being “alyve” might be a matter of degree. After all, scientists already argue about whether viruses qualify – although no one doubts their ability to wreak havoc with life.

He’s sceptical of the notion in Nasa’s working definition that lyfe/life can only arise and develop by Darwinian evolution. He says that even terrestrial organisms can shape their behaviour in ways that don’t depend on Darwin’s mechanism of random mutations coupled to competition for resources that selects advantageous mutations. “While Darwinian evolution does of course occur, I think it needs to be augmented into a larger picture of biological learning,” he says.

Astrobiologist and physicist Sara Walker of Arizona State University agrees. “There might be some systems that have many attributes of life but never cross the threshold to Darwinian life,” she says. But in his new book The Zoologist’s Guide to the Galaxy, Kershenbaum says it’s hard to imagine any other process that could produce complex chemical systems worthy of being considered alive (or alyve). Evolution by natural selection, he says, follows “well-defined principles that we know will apply not just on Earth but elsewhere in the universe” – and he is “very confident that it will be driving the diversity of life on alien planets”. If that’s so, he argues, we can make reasonable assumptions about other attributes it will have: for example that life will have a process like photosynthesis to harvest energy from the parent star.

Bartlett and Wong also question whether lyving things must have sharp physical boundaries. After all, while we might imagine that we are simply everything inside our skin, we depend on other organisms within us: the microbiome of bacteria in our guts. And some philosophers argue that our minds extend beyond our brains and bodies, for example into our technological devices. “We argue for lyfe being a process that probably happens on the scale of whole planets,” says Bartlett. Walker agrees that “the only natural boundary for living processes is the planetary” – reminiscent of Lovelock’s Gaia hypothesis.

But without some confining boundary for the molecular ingredients, says Rothschild, all the components of a living system would get diluted away in its environment, like droplets of ink in water. And Kershenbaum says separate, bounded organisms are needed if evolution is Darwinian, because only then is there something else to compete with.

Walker thinks that in fact Bartlett and Wong don’t go far enough in trying to free ideas about life from terracentrism. Their notion of lyfe, she says, “is kicking down the road many of the problems pervasive in current definitions of life by coming up with a broader definition based on existing ones. It still shares many of the same basic problems. We don’t need new definitions for life. What we need is new theories getting at the underlying principles that govern living physics in our universe.”

Another possibility for broadening our view of what life could be is that we become able to make living systems from scratch in the laboratory that are totally unlike any known. “We’re much closer to that than you might think,” Rothschild says. Indeed, it may have already happened and we didn’t recognise it, she adds, only half-jokingly. If we don’t know what we’re looking for, some researcher might already have made a new form of life – and flushed it down the sink.

In the end, perhaps we shouldn’t be too sure that life fits any natural definition, Rothschild says. “I believe that what we have right now are non-natural definitions of life, because we have only one data point. I wonder whether life is just what we define it to be.”

“We may discover systems that are so weird and unexpected that we can’t quite decide whether they are alive or not,” says Kershenbaum. “But if we discover something really interesting and complex that doesn’t quite fit the definition of life, that’s still a really exciting achievement. We’re not going to ignore it because it doesn’t fit our definition!”


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