Strange objects found near the Milky Way's supermassive black hole

Photos: Wonders of the universe

This is an artist's illustration of a supermassive black hole and its surrounding disk of gas. Inside this disk are two smaller black holes orbiting one another. Researchers identified a flare of light suspected to have come from one such binary pair soon after they merged into a larger black hole.

(CNN)The center of our galaxy, the Milky Way, can be a strange place. It's notoriously hard to see, obscured from our viewpoint by clouds of gas and dust in one of the galaxy's spiral arms.

But 13 years worth of near-infrared wavelength data from the W. M. Keck Observatory in Hawaii has captured the bizarre reality behind the haze.

The supermassive black hole at the center of our galaxy, Sagittarius A*, is behaving strangely and eating voraciously. And now, astronomers have spotted a weird new class of objects not far from the black hole, according to a study published Wednesday in the journal Nature.

"These objects look like gas and behave like stars," said Andrea Ghez, study author, director of the UCLA Galactic Center Group and the university's Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics.

Normally, these objects appear compact. But they stretch out when they near the black hole during their orbits, which can last from 100 to 1,000 years.

This is the latest detection in a mystery that's been unfolding since 2005, when Ghez's research team spotted an object in the center of our galaxy they dubbed G1. In 2012, a second object called G2 was found, and it came close to the black hole in 2014.

The astronomers believe G2 was once really two stars that orbited the black hole together, but merged into one massive star and became obscured by a thick gas and dust cloud.

"At the time of closest approach, G2 had a really strange signature," Ghez said. "We had seen it before, but it didn't look too peculiar until it got close to the black hole and became elongated, and much of its gas was torn apart. It went from being a pretty innocuous object when it was far from the black hole to one that was really stretched out and distorted at its closest approach and lost its outer shell, and now it's getting more compact again."

Now, Ghez's research group has discovered four more objects and determined their orbits: G3, G4. G5 and G6. They're incredibly different orbits from G1 and G2, which were similar to one another.

"One of the things that has gotten everyone excited about the G objects is that the stuff that gets pulled off of them by tidal forces as they sweep by the central black hole must inevitably fall into the black hole," said Mark Morris, study co-author and UCLA professor of physics and astronomy. "When that happens, it might be able to produce an impressive fireworks show since the material eaten by the black hole will heat up and emit copious radiation before it disappears across the event horizon."

The researchers think that all six objects are the result of binary stars -- or pairs of stars that orbit one another -- that were forced together due to the strong gravity of Sagittarius A*.

Ghez said that mergers of stars may be happening in the universe more often than we thought and likely are quite common.

"Black holes may be driving binary stars to merge. It's possible that many of the stars we've been watching and not understanding may be the end product of mergers that are calm now, " Ghez said. "We are learning how galaxies and black holes evolve. The way binary stars interact with each other and with the black hole is very different from how single stars interact with other single stars and with the black hole."

G2 differs from the rest of the objects because it didn't undergo as much stretching as the others.

"Something must have kept it compact and enabled it to survive its encounter with the black hole," said Anna Ciurlo, study author and postdoctoral researcher at UCLA. "This is evidence for a stellar object inside G2."

Now, the astronomers have enough evidence to show a small group of G objects -- rather than a couple of instances -- meaning they can continue analyzing them while searching for others.

The fact that these objects have been found near Sagittarius A*, which likely swallowed up the gas it ripped off the stars, means they could actually be feeding the constantly voracious black hole.

It's further proof that chaos is constantly unfolding at the center of not just the Milky Way but many galaxies in the universe.

"The Earth is in the suburbs compared to the center of the galaxy, which is some 26,000 light-years away," Ghez said. "The center of our galaxy has a density of stars 1 billion times higher than our part of the galaxy. The gravitational pull is so much stronger. The magnetic fields are more extreme. The center of the galaxy is where extreme astrophysics occurs -- the X-sports of astrophysics."

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03-07-2020 om 01:54 geschreven door peter  

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03-07-2020 om 01:42 geschreven door peter  

Why some physicists really think there's a 'mirror universe' hiding in space-time

By Rafi Letzter 

What happens if you turn space-time upside-down?

The Cosmic Microwave Background, pictured here, is the most ancient thing we can see in space. But what's hiding behind it?

(Image: © © ESA and the Planck Collaboration)

A series of viral articles claimed that NASA had discovered particles from another parallel universe in which time runs backward. These claims were incorrect. The true story is far more exciting and strange, involving a journey into the Big Bang and out the other side.

The sensational headlines had muddled the findings of an obscure 2018 paper, never published in a peer-reviewed journal, which argued that our universe might have a mirror reflection across time, a partner universe that stretches beyond the Big Bang. If that's the case, and a series of other extremely unlikely and outlandish hypotheses turn out to be true, the paper argued, then that in turn could explain a mysterious signal hinting that a completely new particle is flying out of the ice in Antarctica.

• Related: The 11 Biggest Unanswered Questions About Dark Matter

The claim that NASA discovered a parallel universe seemed to have been first dreamed up by British tabloid The Daily Star, and the story was then picked up by British and American outlets, including The New York Post. 

Our universe's "mirror"

In order to understand how The Daily Star arrived at its bizarre, viral claim, it's necessary to understand the claims of two separate papers from 2018.

The first paper, by Latham Boyle, a physicist at The Perimeter Institute in Alberta, Canada, and his colleagues, proposed a mirror universe — a reflection of our universe across time. It was published December 2018 in the journal Physical Review Letters (after an appearance on the arXiv server in March that year).

"I think nobody else understands the full sweep of what they have composed," said John Learned, a University of Hawaii astrophysicist and the co-author of a second paper, which builds on Boyle's theory.

Boyle's work is a kind of expansion pack meant to plug holes in the theory that tells the dominant  origin story of the universe: Lambda-Cold Dark Matter (ΛCDM).

ΛCDM explains the cosmos using two key ideas: An unknown dark energy causes the universe to expand. Rewind that expansion far enough backward in time and the whole universe occupies a single point in space. Second, an unseen dark matter gravitationally tugs on stuff in the universe, yet emits no light. This dark matter, the idea goes, accounts for the vast majority of the universe's mass.

"ΛCDM is basically the only game in town," Learned said. "It works in many cases, but there are some somewhat disturbing lapses in the modeling." 

For instance, measurements of expansion don't line up across time, so that measurements made of this expansion based on data from the early universe don’t jive with measurements using data from the modern universe. In addition, ΛCDM can't explain why matter exists at all, since it predicts that matter and antimatter would have formed at equal rates after the Big Bang, and annihilated each other, leaving nothing behind.

• Related: Big Bang to present: Snapshots of our universe through time

Boyle and his colleagues' new universe unwinds the ΛCDM story further back in time, diving into the singularity at the beginning of time and coming out the other side.

Here’s how Boyle’s team sees their theory: Imagine today's universe as a wide, flat circle, sitting on top of yesterday's slightly smaller circle, which sits on top of the yet-smaller circle of the day before that, Boyle said.

Stack up all the circles from today back to the Big Bang, and you'd end up with a cone standing on its point end.

When astronomers look deep into space, they're effectively looking back in time. The most distant galaxy we can see, GN-z11, appears to us as it existed 13.4 billion years ago, or 400 million years after the Big Bang.

Before that, the universe had a "dark age" lasting millions of years, where nothing bright enough for us to see formed. Before that, the universe produced the oldest thing we can see: the Cosmic Microwave Background (CMB), which formed 370,000 years after the Big Bang, as the universe cooled out of a hot, opaque plasma.

Telescopes can't see anything from before the CMB. 

Looking back in time like this, Boyle said, is like looking down through the cosmological cone.

 Image credit: Meghan McCarter)

Viewed in this way, the ΛCDM story ends with the universe coming together into a single point hidden behind the CMB. Boyle's theory looks at the opaque wall the CMB forms across time and draws a different conclusion about what the CMB hides.

The standard view, he said, is that the hot, dense era below the CMB (from our vantage point on the cone) was more or less a "big mess." In ΛCDM cosmology, this is the accelerated period of expansion known as "the epoch of inflation." Back then everything was chaos, the theory states.

But the CMB isn't that chaotic. Its simple structure, according to ΛCDM, emerged after an intense flattening process that wiped away the old mess.

• Related: What's that? Your physics questions answered

"We were interested in exploring a simpler picture where you take the evidence more at face value," he said. "You say 'Okay, we can't see all the way down to the Bang, but we can look darned close, and as close as we look things look super simple. What if we take those observations at face value?'"

This vision of space-time still has a Big Bang hiding behind the CMB, he said.

But "it's much simpler than most of the singularities that arise in Einstein's theory of gravity," he said. "It's a very special type of ultra-simple singularity, where you can follow the solution [to the equations governing space-time] through the singularity." 

Whereas observations go no further back than the CMB, normal cosmological models go a bit further back but still tend to come to a hard stop at the Big Bang. Not in Boyle's scheme.

"You find that it extrapolates, it extends — it analytically continues, physicists would say, to this double cone," he said, referring to the second universe extending away from the Big Bang in time

"It just seems to be the natural, simplest extension of the equations that seem to describe the universe as we see it," he said.

This universe that’s inside the “second cone” is too far down space-time for us to see. Time might seem to run backward there from our reference frame, Learned said. But beings in that universe would still see cause coming before effect, just like we do in ours. Time runs away from the Big Bang in that universe, just like it does in ours. "Away from the Big Bang" in that universe is the opposite direction from the direction of time in our universe. but it doesn't run "backward" in the way we might imagine.

• Related: 5 reasons we may live in a multiverse

Our universe exists on the other side of that universe's ancient history, and that universe exists on the other side of ours.

The "zero particle state"

We have no evidence that this reflected universe exists, Boyle said.

However, he said, "once you have it, it turns out this universe has an extra symmetry, which you didn't see when you were just looking at the top half of the cone."

Symmetries "ring a loud bell" for physicists, Boyle said. They suggest deeper truth.

And this double-cone universe could, in turn, help restore a crack in a symmetry that has bothered physicists for years.

The symmetry in question, known as Charge, Parity, Time (CPT) symmetry states that if you flip a particle to its antimatter twin — an electron into a positron, say — or make it right-handed instead of left-handed, or move it backward through time instead of forward, that particle should still behave in the same way and obey the same laws as it did before getting flipped. (Right-handed or left-handed refers to a particle's spin and direction of movement.)

"Everybody thought these were fundamental symmetries that could not be escaped," Learned said.

Eventually, in 1956, the Columbia University physicist Chien-Shiun Wu led an experiment that established CPT symmetry wasn't absolute. (The two male colleagues who proposed the underlying idea to Wu won the 1957 Nobel Prize for her discovery, but she was left out.)

Wu's experiment showed that the "C" in CPT symmetry is imperfect. And further experiments showed that some particles break both "C" and "P." But though cracked, most physicists think CPT symmetry still holds in general, and no particle has been found that breaks all three elements of this symmetry. At the particle level, the universe appears CPT symmetric.

But the ΛCDM model of the universe itself lacks clear CPT symmetry — a consequence of the curvature of space-time and the strange quantum vacuum. A feature of the universe that Boyle called its "zero particle state," the nature of space-time when emptied of particles, is uncertain. That means that at the scale of all space, CPT symmetry is violated.

Boyle says that his model preserves the universe's CPT symmetry in a way the ΛCDM cosmology does not. Add a second cone to space-time, and the zero particle state is no longer uncertain. The universe's CPT asymmetry is repaired.

"We thought, 'Wait a minute. It seemed like the universe violated CPT symmetry, but actually we just weren't looking at the whole picture," he said. If the universe really is CPT-symmetric, if it really comprises two space-time cones rather than one, what would that mean for the rest of physics?

The truth behind what those "NASA scientists" really detected

The most practical consequence of the CPT-symmetric universe is a simple explanation for dark matter.

One popular set of theories about the unseen stuff relies on the existence of some undetected, fourth type of neutrino — often termed a sterile neutrino. Boyle's CPT symmetry seems to point in this direction. The three known flavors of neutrino, the electron, muon and tau neutrinos, are all left-handed. That means that they fly around without a matching right-handed partner. The Standard Model assumes that, unlike other particles, neutrinos don't have such partners. But the CPT-symmetric universe disagrees, indicating they should have those partners.

Boyle and his colleagues found that their cosmology implies the existence of a right-handed partner in our universe for every left-handed neutrino in the Standard Model. But, unlike left- and right-handed quarks, these left- and right-handed mirror particles wouldn't stick together.Instead, two of the right-handed partner neutrinos would have long since been lost to space-time, decaying out of our view in the very early universe. A third right-handed partner would have stuck around, however ⁠— a consequence of the equations governing the beginning of time.

It's not clear which of the three known neutrinos it would have partnered with, Boyle said. But it would have had a particular energy signature: 480 picoelectronvolts (PeV), a measure of a particle's mass. And that 480PeV neutrino might account for all of that missing dark matter in the universe.

The details of how the CPT-symmetric universe leads to a 480 PeV neutrino are tricky — so tricky, Learned said, that few physicists beyond Boyle and his team understand them at all.

"But these guys are not nutcases," he said. "They're respected members of the field and they know what they're doing. Whether all of that complicated field theory is correct or not, I can't say."

Still, the prediction of a 480 PeV particle jumped out at Learned.

Four years ago, a particle detector hanging from a balloon over Antarctica detected something physics could not explain: Twice, as Live Science previously reported, the Antarctic Impulsive Transient Antenna (ANITA) instrument picked up signals of high-energy particles that seemed to shoot straight up out of the Antarctic ice. (Most researchers involved in ANITA aren't "NASA scientists," but the project does receive NASA funding.)

Particles like this shouldn't exist. None of the known Standard Model particles should have been able to fly all the way through the Earth and burst out the other side at such high energies, but that's what ANITA seemed to be detecting.

As of June 2020, the most popular explanation is that ANITA has detected sterile neutrinos. Learned, who was involved in the early days of the ANITA project, realized the 480 PeV figure lined up nicely with the ANITA findings.

If particles really came from space, then plunged through the Earth to produce the anomaly, they must have decayed just under the Antarctic surface, producing a shower of lighter particles that ANITA detected popping up from the ice. Boyle's 480 PeV dark matter neutrino fit squarely in the mass range that could explain ANITA's decaying mystery particle.

Learned and a team of four other researchers cooked up a scheme where this 480 PeV dark matter neutrino might have pulled off this trick, which they wrote up in a 2018 paper titled "Upgoing ANITA events as evidence of the CPT symmetric universe" and published to the arXiv database. This is the paper The Daily Star turned into a confused headline.

If the ANITA particle really did fit Boyle's scheme, that would be a strong weight on the scale in favor of the two-cone cosmos, Learned said. But it's a long shot. The most important problem they had to solve: getting the particle close enough to Antarctica. Models show that dark matter candidate particles like this 480 PeV neutrino would fall to the center of the Earth soon after running into our planet, leaving none close enough to produce the ANITA anomaly.

These researchers argued that perhaps a recent encounter with a huge, unseen disk of dark matter has stirred up the Earth's 480 PeV neutrinos, leaving some wandering around close to our planet’s surface.

It was an exciting idea to play with, Learned said, but even he is not convinced by his own paper.

"That was our feeble excuse, not thinking of any other good way to do the job [of getting Boyle's neutrinos close enough to Antarctica to trip ANITA's sensors]," Learned said.Though Learned and his colleagues worked hard on the paper, he thinks its conclusions are surely wrong, he said.

"Amongst cosmology folks there's … an idea that you get to use a 'tooth fairy' once in your cosmology model but twice is simply not credible," he said. "And I think we needed the tooth fairy two or three times to make this one work, so, oh well."

Boyle agreed. While the idea of using his team's ideas to explain ANITA was appealing, he said the numbers don't quite add up. But he's still confident the underlying idea of a CPT-symmetric universe is sound.

"My personal hunch is that whether or not it's exactly correct, it's on the right track," he said. "I'm very excited about that."

• The 18 biggest unsolved mysteries in physics
• 5 reasons we may live in a multiverse
• The 11 biggest unanswered questions about dark matter
• Nature's tiniest particles dissected (infographic)

Originally published on Live Science.

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03-07-2020 om 01:24 geschreven door peter  

Firefly Aerospace uses rocket engine to light birthday candles in epic cake video

03-07-2020 om 00:52 geschreven door peter  

Asteroid impact, not volcanic activity, killed the dinosaurs, study finds

An asteroid impact, not volcanic activity, killed the dinosaurs, a new study finds. 

For decades, scientists have gone back and forth over exactly what caused a mass extinction event 66 million years ago, which destroyed about 75% of all life on Earth, including all of the large dinosaurs. Some have thought that volcanic activity could be to blame, but one new study shows that a giant asteroid impact was the prime culprit.

Scientists have known that the impact, which created the massive Chicxulub impact crater (located in what is now the Yucatán Peninsula in southeast Mexico), was a major contributing factor to this extinction event. But volcanic activity happening at around the same time has raised questions over which could have been the main factor which changed conditions on our planet that led to the demise of Earth's creatures.

In a new study, researchers from Imperial College London, the University of Bristol and University College London have shown that the asteroid impact, not volcanic activity, was the main reason that about 75% of life on Earth perished at that time, and it did so by significantly interfering with Earth's climate and ecosystems. 

"We show that the asteroid caused an impact winter for decades, and that these environmental effects decimated suitable environments for dinosaurs. In contrast, the effects of the intense volcanic eruptions were not strong enough to substantially disrupt global ecosystems," lead researcher Alessandro Chiarenza, who conducted this work whilst studying for his PhD in the Department of Earth Science and Engineering at Imperial, said in a statement. "Impact winter" signifies a semi-permanent "winter" created when sunlight-blocking particles are kicked up into the atmosphere after an impact. "Our study confirms, for the first time quantitatively, that the only plausible explanation for the extinction is the impact winter that eradicated dinosaur habitats worldwide."

To come to this conclusion, the researchers modeled how Earth's climate would be expected to respond to two separate possible extinction causes: volcanism and asteroid impact. In these mathematical models, they included environmental factors including rainfall and temperature, which would have been critical to the survival of these species. They also included the presence of sunlight-blocking gases and particles and carbon dioxide, a greenhouse gas. 

"Instead of only using the geologic record to model the effect on climate that the asteroid or volcanism might have caused worldwide, we pushed this approach a step forward, adding an ecological dimension to the study to reveal how these climatic fluctuations severely affected ecosystems," co-lead author Alex Farnsworth, a climatologist at the University of Bristol, added in the same statement. 

With these models, the team found that the giant asteroid hitting our planet would have released tremendous amounts of gas and particles into Earth's atmosphere, blocking out the sun for years on end. This effect would have created a sort of semi-permanent winter on Earth, making the planet unlivable for most of its inhabitants.

Now, while the team found the asteroid impact to be the major factor in making Earth unlivable for most animals, they also found that volcanic activity could have actually helped life to recover over time, a conclusion that scientists have drawn before. 

They found that, while volcanoes do release sunlight-blocking gases and particles, which would have helped to block the sun in the short term, they also release large amounts of carbon dioxide which, because it's a greenhouse gas, would have built up in the atmosphere and warmed the planet. 

So, as the researchers suggest in this work, while the devastating winter caused by the asteroid killed off most life on Earth, over time, the warming effect created from the volcanic greenhouse gases could have helped to restore life to habitats. 

"We provide new evidence to suggest that the volcanic eruptions happening around the same time might have reduced the effects on the environment caused by the impact, particularly in quickening the rise of temperatures after the impact winter. This volcanic-induced warming helped boost the survival and recovery of the animals and plants that made through the extinction, with many groups expanding in its immediate aftermath, including birds and mammals," Chiarenza added. 

• This work was published June 29 in the journal Proceedings of the National Academy of Sciences.

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd.

Follow us on Twitter @Spacedotcom and on Facebook.

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03-07-2020 om 00:34 geschreven door peter  

The Largest Underwater Cave Was Just Discovered And It’s Full Of Mayan Artifacts

One of the most impressive discoveries was made recently in the Mexican city of Tulum in the Yucatan Peninsula. Inside of what appeared to be a random submerged cave they uncovered a set of subterranean caverns that became the largest underwater cave system ever discovered by humanity.

Guillermo de Anda from Mexico’s National Institute of Anthropology and History stated that there are well over a hundred archeological findings in this cave system, and they all relate back to the ancient Mayan civilization.

The team that made the discovery is a part of the Great Maya Aquifer Project or GAM for short. They’ve been working towards discovering more about the ancient Mayan civilization for decades now.

They uncovered 358 cave systems, all submerged underwater, spread across 1,400 kilometers (870 miles). One of the systems was named the Sac Actun System, and thanks to its immense size they believed there to be two cave systems interjecting at first, but after further research, they uncovered that it was all part of the original cave system.

The secondary system was called Dos Ojos System and it was believed to be 93km long (57.8 miles) when it was, later on, uncovered that it was all a part of the Sac Actun System after all.

Article by True Blog.

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03-07-2020 om 00:12 geschreven door peter  

Artist’s concept of Gliese 887b and Gliese 887c orbiting their red dwarf star.

Image via Mark Garlick/ University of Göttingen.

Among the various types of exoplanets discovered so far, those larger than Earth but smaller than Neptune are among the most common. Astronomers call these worlds super-Earths. The nearby TRAPPIST-1 planetary system actually has seven known super-Earths orbiting its star! Now, RedDots researchers at the University of Göttingen in Germany have announced the discovery of another nearby planetary system with at least two super-Earths and possibly a third.

Details of the peer-reviewed findings have been published in the June 26, 2020, issue of the journal Science.

The two planets are orbiting the nearby red dwarf star called Gliese 887 (also known as GJ 887 or Lacaille 9352), which is only 11 light-years away. While not quite within the habitable zone, where liquid water could exist on the surface of rocky worlds, the planets are close to the inner edge of the zone. According to the abstract of the new paper:

The closest exoplanets to the sun provide opportunities for detailed characterization of planets outside the solar system. We report the discovery, using radial velocity measurements, of a compact multiplanet system of super-Earth exoplanets orbiting the nearby red dwarf star GJ 887. The two planets have orbital periods of 9.3 and 21.8 days. Assuming an Earth-like albedo, the equilibrium temperature of the 21.8-day planet is ~350 kelvin [-623 Celsius or -1,090 Fahrenheit]. The planets are interior to, but close to the inner edge of, the liquid-water habitable zone. We also detect an unconfirmed signal with a period of ~50 days, which could correspond to a third super-Earth in a more temperate orbit. Our observations show that GJ 887 has photometric variability below 500 parts per million, which is unusually quiet for a red dwarf.

Illustration depicting the size of a super-Earth called CoRoT-7b. Super-Earths are larger and more massive than Earth, but smaller and less massive than Neptune.

Image via Aldaron/ Wikipedia.

Super-Earths are one of the most common types of planets in our galaxy. Some of them may be habitable for some kind of life to exist.

Image via NASA/ JPL-Caltech/ R. Hurt (SSC-Caltech)/ Earth Magazine.

The temperature of Gliese 887c has been estimated at 158 degrees Fahrenheit (70 degrees Celsius). A bit hot, but perhaps not enough to render the planet uninhabitable. If the third planet does exist, it could have cooler temperatures since it is in a more temperate orbit within the habitable zone.

The planets were discovered using the “Doppler Wobble” technique, which enables the researchers to measure the tiny back and forth wobbles of the star caused by the gravitational pull of the planets. The researchers used the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph at the European Southern Observatory (ESO) in Chile.

Red dwarf stars, although smaller and dimmer than our sun, are known for typically being very active, emitting strong bursts of radiation that could strip close-in planets of their atmospheres and make conditions difficult or impossible for life to exist. But Gliese 887 has only a very few star spots and appears to be less active than most red dwarfs. That’s good news for the possibility of any of the planets retaining their atmospheres and perhaps being habitable.

In a related Perspective article, Melvyn Davies wrote:

If someone had to live around a red dwarf, they would want to choose a quieter star like GJ 887. If further observations confirm the presence of the third planet in the habitable zone, then GJ 887 could become one of the most studied planetary systems in the solar neighborhood.

Red dwarf stars are known for being very active, emitting powerful blasts of solar radiation, which can strip atmospheres off planets that are too close, as in this artist’s concept. But Gliese 887 is less active than most red dwarfs, increasing the chance that some of its planets might be potentially habitable.

Image via NASA/ Ames/ JPL-Caltech/ HowStuffWorks.

The Gliese 887 worlds will also be ideal candidates for follow-up studies by the upcoming James Webb Space Telescope (JWST), not only because they are close by, but also because the brightness of the star is almost constant, making it easier to detect any atmospheres. As Sandra Jeffers, from the University of Göttingen and lead author of the study, said in a statement:

These planets will provide the best possibilities for more detailed studies, including the search for life outside our solar system.

The discovery reinforces two previous findings about exoplanets: one, super-Earth worlds are common (as well as Earth-sized planets), even though there isn’t one in our solar system (unless the elusive Planet Nine turns out to be one, as some scientists think), and two, exoplanets are abundant around red dwarf stars, which are the most common stars in our galaxy. This is exciting, since many, if not most, super-Earths are thought to be rocky like our own planet. But we still don’t know how habitable these kinds of worlds could be. Scientists think that some super-Earths could have extensive or even global oceans. Others might be dry and barren.

Sandra Jeffers at the University of Göttingen in Germany, lead author of the new study.

Image via University of Göttingen.

New upcoming telescopes like JWST will be able to take a closer look at some of these worlds, and provide a much better idea of what the actual conditions are like. If there are millions or billions of them in our galaxy, as seems likely – and scientists now say there are more exoplanets in total than stars, including an estimated six billion ‘Earth-like’ planets – then it seems reasonable that some of them should be potentially habitable.

• Bottom line: Astronomers have discovered two, and possibly three, super-Earth exoplanets orbiting a nearby red dwarf star.
• Source: A multiplanet system of super-Earths orbiting the brightest red dwarf star GJ 887
• Via University of Göttingen
• Via EurekAlert!

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02-07-2020 om 23:46 geschreven door peter  

Astronomers from Western University in Canada have discovered six more possible exomoons orbiting distant exoplanets, in data from the Kepler Space Telescope.

Artist’s concept of a habitable exomoon orbiting a distant exoplanet similar to Saturn. Astronomers have now discovered what may be 6 more exomoons orbiting exoplanets ranging from 200 to 3,000 light-years away. There are hundreds of moons in our own solar system, and some of them have subsurface water oceans. How many similar ocean moons may be out there?

Image via SpaceRef/ Astrobiology Web.

Our solar system is filled with hundreds of moons, many more moons than planets. But what about distant solar systems? We now know of well over 4,000 confirmed exoplanets – or planets orbiting distant stars – 4,171 right now, to be exact. Yet there’ve been, so far, still only a few possible detections of exomoons. It makes sense, given that moons of planets tend to be smaller and thus more difficult to find than planets themselves. But now scientists at Western University in London, Ontario, Canada, have announced that they might have spotted six more exomoons!

The potentially exciting findings have been submitted in a new paper to the Monthly Notices of the Royal Astronomical Society, with a preprint version posted on arXiv on June 23, 2020.

The possible moons are not confirmed yet, but the results seem promising. As Paul Wiegert, co-author of the study, noted in a statement:

We know of thousands of exoplanets throughout our Milky Way galaxy, but we know of only a handful of exomoon candidates.

From the paper:

Here we explore eight systems from the Kepler data set to examine the exomoon hypothesis as an explanation for their transit timing variations, which we compare with the alternate hypothesis that the TTVs are caused by an non-transiting planet in the system. We find that the TTVs of six of these systems could be plausibly explained by an exomoon, the size of which would not be nominally detectable by Kepler. Though we also find that the TTVs could be equally well reproduced by the presence of a non-transiting planet in the system, the observations are nevertheless completely consistent with a existence of a dynamically stable moon small enough to fall below Kepler’s photometric threshold for transit detection, and these systems warrant further observation and analysis.

So where are these moons and how were they potentially found?

The moons are in data from the Kepler Space Telescope mission, which ended in 2018. The host planets range from about 200 to 3,000 light-years away, and were discovered by the transits that the planets made in front of their stars, which caused the star’s brightness to dim slightly and briefly. Most exoplanets are found using the transit method. But the moons are much smaller and dimmer, so they are very difficult to detect by any method. Wiegert said:

These exomoon candidates are so small that they can’t be seen from their own transits. Rather, their presence is given away by their gravitational influence on their parent planet.

The six moon candidates are (KOI) 268.01, Kepler 517b (KOI-303.01), Kepler 1000b (KOI-1888.01), Kepler 409b (KOI-1925.01), Kepler 1326b (KOI-2728.01) and Kepler 1442b (KOI-3220.01). KOI refers to Kepler Object of Interest.

So how might these moons reveal themselves?

Usually, the transit of a planet occurs precisely at regular timed intervals, the same as how planets orbit our own sun. But sometimes, that precise timing is actually variable. This means that the gravity of some other body, another planet or a moon, must be affecting it. These variations are called transit timing variations (TTVs). The results fit with what would be expected of exomoons, but could still possibly be explained by other planets in these systems instead. As Fox explained:

Because exoplanets are more massive than exomoons, most TTVs observed to date have been linked to the influence of other exoplanets. But now we’ve uncovered six Kepler exoplanet systems whose TTVs are equally well explained by exomoons as by exoplanets. That’s why we’re calling them exomoon ‘candidates’ at this point as they still need follow-up confirmation.

TTVs were also found for two other exoplanets, KOI-1503.01 and KOI-1980.01, but those are thought to be caused by other planets in the systems instead of moons and were ruled out.

Artist’s concept of the possible huge exomoon orbiting the exoplanet Kepler-1625b, found by the Hubble Space Telescope in 2018.

Image via HubbleSite.

That confirmation may have to wait a while, however, since current telescopes can’t do it; it will require telescopes that are being planned and designed, but not built yet. Fox said:

We can say these six new systems are completely consistent with exomoons: their masses and orbits are such that they would be stable; they would be small enough that their own transits wouldn’t be seen; and they reproduce the pattern of TTVs seen throughout the entire Kepler data set. But we don’t have the technology to confirm them by imaging them directly. That will have to wait for further advancements.

It is exciting to contemplate what kinds of alien exomoons are out there. Just in our own solar system, there is a huge variety of these smaller worlds, from gray, cratered and moon-like, to Io, which kind of looks like a pizza and has the most active volcanoes of any object in the solar system, to ocean worlds like Europa, Enceladus and others. The icy moons with subsurface oceans are especially appealing, since they could be habitable by earthly standards. There are several of them in our solar system alone, so how many more might be out there? What kind of life might exist on such worlds? Chris Fox, who made the discoveries, said:

Our own solar system contains hundreds of moons. If moons are prolific around other stars, too, it greatly increases the potential places where life might be supported, and where humankind might one day venture.

Chris Fox at Western University, who discovered the possible new exomoons.

Image via CBC.

Fox makes a very good point. Since our own solar system has hundreds of moons orbiting six out of the eight planets, is it not reasonable that many of the planets in other solar systems would also have their own moons? And as we are now discovering, a good number of the moons in our solar system are indeed potentially habitable, with their subsurface water oceans.

In 2018, Fox also discovered Kepler-159d, an exoplanet about the size of Saturn, which orbits its star in only 88 days.

In 2014, another possible exomoon, dubbed MOA-2011-BLG-262 exoplanet-exomoon system, was discovered, where the moon would be less massive than Earth and the planet would be more massive than Jupiter. In 2018, the Hubble Space Telescope (HST) found what may be a huge exomoon orbiting the gas giant planet Kepler-1625b. It’s also still not confirmed yet, but if real, is about the size of Neptune! If the new findings from Western University are any indication – and confirmed – then there may many more exomoon discoveries to look forward to.

• Bottom line: Astronomers examining data from the Kepler Space Telescope appear to have discovered six more exomoons. Although the result awaits confirmation, it has the potential to be a big step forward in understanding distant solar systems.
• Source: Exomoon Candidates from Transit Timing Variations: Six Kepler systems with TTVs explainable by photometrically unseen exomoons
• Via Western News

{ https://earthsky.org/ }

02-07-2020 om 23:20 geschreven door peter  

A Sun a day keeps dark matter away?

by Tibi Puiu in News, Space

Astronomers have come across a monstrously large black hole with a gargantuan appetite. Each passing day, the insatiable void known as J2157 consumes gas and dust equivalent in mass to the sun, making it the fastest-growing black hole in the universe.

The sheer scale of J2157 is almost unfathomable, but we can try pinning some numbers on it nevertheless.

According to Christopher Onken, an astronomer at the Australian National University who was part of the team that originally discovered the object in 2019, J2167 is 8,000 times more massive than the supermassive black hole found at the heart of the Milky Way. That’s equivalent to 34 billion times the mass of the Sun.

In order for Sagittarius A*, the Milky Way’s supermassive black hole, to reach a similar size, it would have had to gobble two-thirds of all the stars in the galaxy.

For their new study, astronomers turned to ESO’s Very Large Telescope in Chile to get a more accurate assessment of the black hole‘s mass. The researchers already knew they were dealing with a black hole of epic proportions, but the final results surprised everyone.

“We knew we were onto a very massive black hole when we realized its fast growth rate,” said team member Dr. Fuyan Bian, a staff astronomer at ESO.

“How much black holes can swallow depends on how much mass they already have.  So, for this one to be devouring matter at such a high rate, we thought it could become a new record holder. And now we know.” 

Although black holes can’t be imaged directly because they don’t let light escape, J2157 is actually classed as a quasar, or “quasi-stellar radio source” — extremely bright objects powered by black holes at least a billion times as massive as our sun.

The bright signal of the quasar is formed by particles of dust and gas accreting around the edge of the supermassive black hole that are accelerated away at almost the speed of light. Practically, the black hole acts like an extremely powerful natural particle accelerator.

Luckily for us, the black hole is located many billions of light-years away. But this also means that astronomers are measuring J2157’s gravitational influence as it appeared in the distant past when the universe was still very young.

“We’re seeing it at a time when the universe was only 1.2 billion years old, less than 10 percent of its current age,” Dr Onken said. 

“It’s the biggest black hole that’s been weighed in this early period of the Universe.” 

Since then, J2157 likely grew even bigger, perhaps merging with several other black holes across the eons.

“With such an enormous black hole, we’re also excited to see what we can learn about the galaxy in which it’s growing,” Dr Onken said. 

“Is this galaxy one of the behemoths of the early Universe, or did the black hole just swallow up an extraordinary amount of its surroundings? We’ll have to keep digging to figure that out.” 

• The findings appeared in the Monthly Notices of the Royal Astronomical Society.

{ https://www.zmescience.com/ }

02-07-2020 om 22:55 geschreven door peter  

If Gene Roddenberry were alive today, he might look at the newly-formed US Space Force and wonder if the current administration owes him royalties. After all, the command responsible for the organization, training, equipping, commanding and controlling space forces is called SpOC (Space Operations Command} and their logo looks like the Starfleet emblem. And this week, the five-tiered bureaucracy of squadrons, groups, wings, numbered Air Forces, and major commands was replaced by a threesome of squadrons, field commands and ‘deltas’. Deltas? Does that sound familiar, Spock?

“This is the most significant restructuring of space units undertaken by the United States since the establishment of Air Force Space Command in 1982. Innovation and efficiency are driving our mission as we position the Space Force to respond with agility to protect our nation’s space capabilities and the American way of life.”

According to the Air Force press release, Secretary of the Air Force Barbara Barrett announced the restructuring this week as a way of making the organization “lean, agile and mission-focused.” However, “to protect our nation’s space capabilities and the American way of life” is a far cry from “to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no one has gone before.” Give it a chance, some say. Perhaps the Space Force will steal the Enterprise’s mission statement someday too, just like it has now taken ‘Delta’ – one of the most used words across the entire Star Trek world.

“Deltas will be O-6 led and will be organized around a specific function – operations, installation support, training, etc. Within the deltas will be squadrons focused on specific tactics. When the field command structure is fully implemented, it will eliminate one general officer echelon and one O-6 echelon of command.”

Well, that’s not exactly any of the Star Trek Deltas. The most famous one is the Starfleet insignia itself. The delta-shaped emblem was created by costume designer William Ware Theiss and was paired with other symbols to designate divisions: an elongated star for the Command division aboard ship; a planet for the Sciences division; an “e” stands for Engineering; and a red “Swiss Cross” for the Nursing Corps. In the Star Trek movies, Delta (or Delta IV) was a Federation planet inhabited by the humanoid Deltans. And on Star Trek:Voyager, the Delta Flyer was a shuttlecraft.

Do you see the connection, Mr. Spock?

However, the most famous of the Star Trek ‘Deltas’ was the Delta Quadrant – home of the Borg Collective and the area where the USS Voyager got stranded and spent the bulk of the series trying to escape. Other residents of the Delta Quadrant were the Kazon, the Vidiians, the Talaxians, the Ocampa, the Hirogen, and the Malon.

Patterning the Space Force after Star Trek would actually be a good idea – if it took the high concepts of Roddenberry’s creation rather than just cherry-picking names and logos. Unfortunately, the chance is also there that it will instead pick up the mission, or even worse, the attitude, of a very different group of Deltas — the fraternity from “Animal House.”

Let’s hope at least a few of the heads of the Space Force are Trekkies.

{ https://mysteriousuniverse.org/ }

02-07-2020 om 22:20 geschreven door peter  

“First there is a mountain, then there is no mountain, then there is”
‘There Is a Mountain‘ by Donovan

Rock and Roll Hall of Fame member Donovan Leitch was inspired by a Buddhist saying to write those lyrics about finding one’s true nature. If a mountain can disappear, can something bigger … like a star? That the question astronomers are pondering after a massive star in a strange dwarf galaxy suddenly blinked out of existence and left nothing behind to indicate what happened or where it went. The next lines of the song compares it to a caterpillar shedding its skin to transform into a butterfly. Did this star shed its life and transform into something else other than a black hole? If so, this would be a first. Is it? Donovan? Buddhists?

“We investigate a suspected very massive star in one of the most metal-poor dwarf galaxies, PHL 293B. Excitingly, we find the sudden disappearance of the stellar signatures from our 2019 spectra, in particular the broad H lines with P Cygni profiles that have been associated with a massive luminous blue variable (LBV) star.”

In a research paper published this week in the Monthly Notices of the Royal Astronomical Society, astronomers from around the world reveal how the massive star they had studied between 2001 and 2011 suddenly disappeared when they went for a look in 2019. Located in the Kinman Dwarf (PHL 293B) galaxy in the Aquarius constellation about 75 million light years from Earth, this was a luminous blue variable star about 2.5 million times brighter than the Sun and in the latter stages of its life – although certainly not on its deathbed. Or so they thought.

“It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion.”

Where was the supernova explosion?

In a European Southern Observatory (ESO) press release announcing the study, team leader and PhD student Andrew Allan of Trinity College Dublin describes using the ESPRESSO instrument (Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations) of the ESO’s Very Large Telescope (VLT) and the VLT’s four 8-metre telescopes simultaneously in August 2019. Finding no sign of the star, they suspected and error and switched to the VLT’s X-shooter instrument (“the ultimate weapon in intermediate resolution spectroscopy across a wide wavelength range, from the ultraviolet (UV) to the near-infrared (NIR)”) and still found no sign of the massive luminous star. With the Kinman Dwarf galaxy being too far away to see individual stars, they went back to older data which gave the astronomers a clue to what they had really been looking at.

“The old data indicated that the star in the Kinman Dwarf could have been undergoing a strong outburst period that likely ended sometime after 2011. Luminous blue variable stars such as this one are prone to experiencing giant outbursts over the course of their life, causing the stars’ rate of mass loss to spike and their luminosity to increase dramatically.”

Ah-ha! The luminous blue variable star was luminous because it was in a last blast of brightness  and on its way out in 2011, or already “going gently into the night,” as team member Jose Groh, also of Trinity College Dublin, described it. As a result, the star may have dimmed considerably and is now blocked by a dust cloud. Or, the star collapsed into a black hole without producing a supernova – something only known to have occurred once before. As expected, the astronomers hope it’s the latter option, but can’t prove it because they can’t see the black hole … yet.

“Planned to begin operations in 2025, ESO’s Extremely Large Telescope (ELT) will be capable of resolving stars in distant galaxies such as the Kinman Dwarf, helping to solve cosmic mysteries such as this one.”

Will it come back?

Will they find a non-supernova black hole where the star was first? Donovan?

“Caterpillar sheds his skin to find a butterfly within.”

Then what?

“First there is a mountain, then there is no mountain, then there is”

Astronomy, like Buddhism and rock singers, can be comforting and frustrating at the same time.

Videos, selected by peter2011

{ https://mysteriousuniverse.org/ }

02-07-2020 om 22:05 geschreven door peter  

Iceland Earthquake Swarm Hits 9,000 Quakes in 10 Days

In an email to Newsweek, Jónsdóttir said the swarm is happening in a known fault zone called the Tjörnes Fracture zone. "Stress builds up in the zone because of tectonic plates which move past each other in opposite directions. This is the largest earthquakes swarm in the Tjörnes Fracture Zone recorded in the past 40 years."

Image showing the earthquake swarm to the north of Iceland.

IMO

02-07-2020 om 18:24 geschreven door peter  

02-07-2020 om 18:06 geschreven door peter  

Explain: Until 12/10/2014 6am there is nothing to see on the ice sheet between Hutchinson Island and Cronenwell Island at Antarctica, then 1 hour later on 12/10/2014 7am the shadow of an enormous medieval castle becomes visible on the same spot.

Something went wrong with the Google Earth image processing or the appearance of the shadow is a mysterious and unexplained holographic projection from the past when it used to be ice-free until about 34 million years ago, before it became covered with ice. 

Here are the coordinates: 76°52'13.87"S 149°59'14.52"W

{ http://ufosightingshotspot.blogspot.com/ }

02-07-2020 om 17:23 geschreven door peter  

Inspired by an essay by Barjavel, the 70-year-old documentary proposes the evolution of television in transportable pocket format, and the way in which humans will interact with the objects. Today, parallels are drawn between the objects, like smartphones, described in the short documentary.

Anne-Katrin Weber, a historian of television at the University of Lausanne, said:

People using miniature-television devices in public places; professional meetings conducted via picture-phones; cars equipped with television screens; shops promoting their goods on television: these snapshots are taken from the 1947 short film Télévision: Oeil de Demain. Produced and shot by J. K. Raymond-Millet, Télévision.

Oeil de Demain combines documentary and science fiction sequences as it simultaneously offers a depiction of television in postwar France as well as imaginative speculations of the medium’s future developments.

While Raymond-Millet’s work is virtually forgotten today, his film Télévision has been applauded for ‘predicting our present’ and although the small handheld devices used in the film have long retractable antennas that resemble the first cell phones, it shows that '70 years ago, smartphones already existed. Actually they do mirror today’s smartphones that are in the pockets of nearly every human.

At the end of the movie, viewers are transported to the bedroom of a couple where a man is having trouble sleep. He seems to 'summon' a holograph of a dancing woman that appear at the bottom of the bed and watches it while his wife sleeps besides him.

The film’s sketching of coming televisual uses indeed appears as a rather precise forecasting of contemporary digital media with regard to the flexibility and hybridity of media technologies and their various consumption forms.

{ http://ufosightingshotspot.blogspot.com/ }

02-07-2020 om 17:12 geschreven door peter  

Dead Alien Body Still Laying On Surface Of Mars, NASA Rover Photo! UFO Sighting News.

Date of discovery: July 1, 2020

Location of discovery: Mars, MSL 2790 ML

Source photo: 

• http://gigapan.com/gigapans/221573

Now this is rare. Its not everyday you find a humanoid body laying on the surface of an alien planet. The body remains mostly intact and is defiantly not a statue. The legs are boney and dried out. One leg is even broken off at the knee. The other leg is mostly intact with a foot at the end. The chest and lower stomach area is different from humans in that its more reptilian like. The ribs seem to extend extremely low. The upper arms are less visible, but one arm can be seen behind the persons shoulder. The neck, ear, cheek, nose, eye and hair are all easily seen. The focus of the person is great, the quality of the photo is high. There is no doubt in my mind that this was an intelligent being which stood about 2 meters tall on Mars. For it to still exist, only two possibilities exit...first, its DNA is more than 2 different strands like we have, it must have 6-10 strands or more for its body to be so difficult to break down in the environment. Or second, it died recently. 

I also found some other anomalies that are proof of alien life, but they pale in comparison to the alien body. You can see them below. 

Thanks, 

Scott C. Waring - Taiwan 

• Please help my UFO research at https://paypal.me/ScottWaring?locale.x=en_US

Below is a long face in the rock. I colored the side hair yellow and skin green, tongue pink. 

Other videos, selected by peter2011

{ https://www.etdatabase.com/ }

02-07-2020 om 16:59 geschreven door peter  

Ancient Aliens: The Ultimate Guide to UFOs S15E11

Ancient Aliens – The Ultimate Guide to UFOs
History Channel, Season 15 Episode 11
11th April 2020

Researchers shows various evidence of UFOs and its sightings through past. And discuss about the UFOs having different shapes and appearances. If different shapes of UFO have different vehicular uses.

Other videos, selected by peter2011

{ https://www.latest-ufo-sightings.net/ }

02-07-2020 om 15:40 geschreven door peter  

A 200,000 Year Old Annunaki Gold Civilization Might Rewrite History Books

The discovery of ancient or even unknown civilizations has always fascinated archaeologists and scientists because such findings have added up to the known history by bringing in new episodes depicting the achievements of the old people who once dwelt on planet Earth.

However, when a team of archaeologists investigated this particular site, they couldn’t find a link between it and any other known culture. After carbon-14 was used in order to find the approximate time-period of the African remains, the archaeologists and historians were perplexed – the ruins were around since 160,000 to 200,000 years before Christ.

What makes this even more interesting is the fact that no advanced civilizations were thought to exist in South Africa in the past and that the first powerful cultures appeared in Sumeria, Egypt and other places.

When researcher and author, Michael Tellinger, teamed up with Johan Heine, a local pilot who had surveilled the area from above countless times, this mysterious settlement and its extreme importance was finally brought into discussion.

West of the port city of Maputo, about 150 miles inland, lies the remains of a colossal ancient metropolis that measures about 1,500 square miles and is considered part of an even larger picture measuring about 10,000 miles. Until recently, local people who encounters the strange stone foundations thought they were built by the indigenous people in the past and no one was attracted in discovering the exact origins, until Tellinger and Heine arrived.

When Heine first introduced me to the ancient stone ruins of southern Africa, he had no idea of the incredible discoveries we would achieve in the following years. The photographs, artifacts and evidence we accumulated, points towards a lost civilization that has never before been and precedes all others – not for a hundred years, or a few thousand years…but many thousands of years. – said Tellinger

The researchers were puzzled by the presence of so many gold mines remnants located in the vicinity of the ancient city. As Tellinger considers, this striking element shows how a timeworn civilization lived and prospered in this massive city while undertaking massive gold exploitations from the numerous mines around the settlement.

What they did with the gold remains a mystery because not much is known about a period so far away in time. Even though the site is only 150 miles away from an excellent port that could had facilitated a great way to ship their goods, we are still talking about 200,000 BC. Is it possible that they used the gold for trade or for sculpting statues and idols? Or could this enigmatic material possess a different, nobler value for these ancient people?

I see myself a fairly open-minded chap but I will admit that it took me well over a year for the penny to drop, and for me to realize that we are actually dealing with the oldest structures ever built by humans on Earth.

The main reason for this is that we have been taught that nothing of significance has ever come from southern Africa. That the powerful civilizations all emerged in Sumeria and Egypt and other places. We are told that until the settlement of the Bantu people from the north, which was supposed to have started sometime in the 12^th century AD, this part of the world was filled by hunter gatherers and so-called Bushmen, who did not make any major contributions in technology or civilization. – Tellinger

The ancient ruins are scattered over an extremely large area. While most of them consist of circular stone circles buried in the sand, the climate change has blown the sand off, revealing other imposing structures with walls standing as high as 5 feet, while being over a meter in diameter; also roads were discovered, some extended over hundreds of miles, connecting the community and terraced agriculture.

{http://ufoholic.com/}

02-07-2020 om 01:51 geschreven door peter  

NASA wants to use a steam-powered robot to explore icy moons that could host alien life

By Chris Ciaccia | Fox News

NASA's plans to explore the ice moons of the Solar System are getting more detail as the space agency is developing a robot that would use steam to power itself in deep space.

In a post to its website, NASA's Jet Propulsion Laboratory notes researchers are developing a soccer-ball sized robot known as SPARROW (Steam Propelled Autonomous Retrieval Robot for Ocean Worlds) that "would use steam propulsion to hop across the sort of icy terrains found on Jupiter's moon Europa and Saturn's moon Enceladus."

"The terrain on Europa is likely highly complex," said Gareth Meirion-Griffith, JPL roboticist and the lead researcher of the concept, in the statement. "It could be porous, it might be riddled with crevasses, there might be meters-high penitentes" - long blades of ice known to form at high latitudes on Earth - "that would stop most robots in their tracks. But SPARROW has total terrain agnosticism; it has complete freedom to travel across an otherwise inhospitable terrain."

Moons In this artist's concept, a SPARROW robot uses steam propulsion to hop away from its lander home base to explore an icy moon's surface.

(Credit: NASA/JPL-Caltech)

• SATURN'S MYSTERIOUS MOON COULD SUPPORT ALIEN LIFE THANKS TO THIS NEW DISCOVERY

Both moons have been mentioned as candidates to possibly host life previously, including one study published in December 2019 that suggested they could be "indigenous."

By using steam to power the robot, SPARROW could thrive in the "low-gravity environment" on Enceladus and Europa, hopping "many miles over landscapes that other robots would have difficulty navigating," NASA added.

With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist. 

(NASA/JPL-Caltech)

• ALIEN LIFE ON SATURN'S MOON? DUST STORMS ON TITAN SPOTTED FOR THE FIRST TIME

Enceladus and Europa both likely have oceans that exist under a layer of ice crust. In 2019, researchers determined Enceladus' ocean is likely 1 billion years old, placing it in the sweet spot for supporting life.

In 2018, researchers acknowledged they had found the "building blocks" for life on Enceladus, having discovered complex organic molecules.

JPL notes that the SPARROW concept is dependent upon a lander to serve as a home base for it. The lander would "mine ice and melt it" prior to putting it on SPARROW, which would later heat it and create the steam necessary to power itself.

An artist's illustration of a plume of water vapor emanating from Jupiter's

moon Europa. 

(NASA/ESA/K. Retherford/SWRI) (NASA/ESA/K. Retherford/SWRI)

• WATER SPOTTED IN JUPITER'S ATMOSPHERE

JPL added that it's possible "many SPARROWs could be sent together, swarming around  a specific location or splitting up to explore as much alien terrain as possible."

Enceladus is not the only celestial satellite of Saturn to intrigue scientists. In June, NASA announced the latest mission in its New Frontiers program. Known as Dragonfly, the mission will explore Saturn's largest moon, Titan, which could potentially host extraterrestrial life.

Two months later, NASA confirmed it would launch a mission to Europa, a trek that could answer whether the icy celestial body could be habitable for humans and support life.

{ https://www.foxnews.com/ }

02-07-2020 om 01:36 geschreven door peter  

A new study from scientists in the UK suggests that atmospheric dust could increase the habitability of some exoplanets, especially those orbiting red dwarf stars.

Three computer simulations depicting how airborne dust can be distributed by winds on rocky exoplanets like Earth.

Image via Denis Sergeev/ University of Exeter/ ScienceAlert.

What makes a planet habitable? Various factors can affect a planet’s ability to sustain life, such as temperature, amount of water, composition of both the planet and its atmosphere and the amount of radiation from the host star. Last month, researchers in the U.K. said they’ve found that a common component of atmospheres – dust – could increase the habitability of some exoplanets.

The peer-reviewed results were published in Nature Communications on June 9, 2020.

This is a significant finding, since it suggests that planets with a lot of dust in their atmospheres could have habitable conditions farther from their stars than previously thought. This would, in effect, expand the habitable zone, which is basically the region around a star where temperatures on a rocky could allow liquid water to exist.

Researchers from the University of Exeter, the Met Office and the University of East Anglia (UEA) were involved in the new study.

Effects of dust on the climate of planets. For a tidally locked planet (a) and non-tidally locked planet (b), panels a–d show the base state of the planets, e–h show the short- (stellar) and long-wave (infra-red) forcing (change in surface energy balance) introduced by dust and i–j show the resultant effect of the forcing on the surface temperature. Blue arrows show the motion of the planet around the star, and green arrows show the rotation of the planet relative to the star. 

Image via Boutle et al./ Nature Communications.

From the paper:

Identification of habitable planets beyond our solar system is a key goal of current and future space missions. Yet habitability depends not only on the stellar irradiance, but equally on constituent parts of the planetary atmosphere. Here we show, for the first time, that radiatively active mineral dust will have a significant impact on the habitability of Earth-like exoplanets.

In our own solar system, Mars typically comes to mind when we think of a dusty world, yet it remains a cold, dry planet on the surface due to its very thin atmosphere. But for some exoplanets, especially those that are tidally locked to their stars, it could be a different situation. Ian Boutle, from both the Met Office and University of Exeter and lead author of the study, said in a statement:

On Earth and Mars, dust storms have both cooling and warming effects on the surface, with the cooling effect typically winning out. But these ‘synchronised orbit’ planets are very different. Here, the dark sides of these planets are in perpetual night, and the warming effect wins out, whereas on the dayside, the cooling effect wins out. The effect is to moderate the temperature extremes, thus making the planet more habitable.

The dust factor is especially significant for planets orbiting red dwarf stars, the most common type of star in our galaxy. Many planets around those stars are likely to be tidally locked, orbiting with one side of the planet always facing the star, just as the moon always keeps one side facing Earth. Those planets would have one side always in daylight, and the other always in darkness. If there is a lot of dust, that could help cool down the hotter day side, and warm the colder night side.

Artist’s concept of a cloudy and rocky exoplanet orbiting a red dwarf star. Dust in the atmospheres of planets like this could moderate the temperature extremes if the planets are tidally locked, helping to make them more habitable.

Image via L. Hustak/ J. Olmsted (STScI)/ NASA.

In an interesting scenario, dust could help hot planets retain their surface water, if they have any. A planet that is really hot, like Venus, could be cooled down by enough dust in the atmosphere. The amount of dust would then increase as water starts to be lost on the planet’s surface, which, ironically, in a process called negative climate feedback, would then slow down the loss of water. From the paper:

On tidally-locked planets, dust cools the day-side and warms the night-side, significantly widening the habitable zone. Independent of orbital configuration, we suggest that airborne dust can postpone planetary water loss at the inner edge of the habitable zone, through a feedback involving decreasing ocean coverage and increased dust loading.

The amount of energy a planet receives from its star is an important part of assessing habitability, but as Manoj Joshi from UEA noted, the composition of the atmosphere, including dust, is also very important:

Airborne dust is something that might keep planets habitable, but also obscures our ability to find signs of life on these planets. These effects need to be considered in future research.

The researchers performed a series of simulations of rocky Earth-sized planets and found that naturally occurring mineral dust can have a big impact on the habitability of such planets.

Mars is a very dusty place, and massive dust storms are common, but the dust doesn’t warm the planet much since the atmosphere is so thin.

Image via SA/ Roscosmos/ CaSSIS/ CC BY-SA 3.0 IGO/ New Scientist.

Duncan Lyster, who ran an undergraduate experiment as part of the overall study (and now builds his own surfboards), also said:

It’s exciting to see the results of the practical research in my final year of study paying off. I was working on a fascinating exoplanet atmosphere simulation project, and was lucky enough to be part of a group who could take it on to the level of world-class research.

The researchers also point out that dust in a planet’s atmosphere must be taken into account when searching for possible biomarkers in that atmosphere. Those biomarkers could include gases such as oxygen, methane and ozone, and if there also was enough dust, the dust could obscure the detection of them, producing a false negative result. If potential biomarkers were missed in that way, the planet might be erroneously characterized as uninhabitable. Such biomarkers, which will be searched for with upcoming space telescopes like the James Webb Space Telescope (JWST) and others, will be a crucial aspect of the search for evidence of life beyond our solar system. Identifying them is already a challenge due to the extreme distances to these worlds, so knowing the amount of dust in a planetary atmosphere will be important as well. From the paper:

The inclusion of dust significantly obscures key biomarker gases (e.g. ozone, methane) in simulated transmission spectra, implying an important influence on the interpretation of observations. We demonstrate that future observational and theoretical studies of terrestrial exoplanets must consider the effect of dust.

Ian Boutle at the Met Office and University of Exeter, lead author of the new study.

Image via Google Scholar.

Nathan Mayne from the University of Exeter, who assisted with the study, also noted how astrophysics in general will play a large role. He said:

Research such as this is only possible by crossing disciplines and combing the excellent understanding and techniques developed to study our own planet’s climate, with cutting edge astrophysics. To be able to involve undergraduate physics students in this, and other projects, also provides an excellent opportunity for those studying with us to directly develop the skills needed in such technical and collaborative projects. With game-changing facilities such as the JWST and E-ELT, becoming available in the near future, and set to provide a huge leap forward in the study of exoplanets, now is a great time to study physics!

The new assessment regarding exoplanetary dust will be very beneficial to scientists who will be looking for biomarkers and other evidence for habitable exoworlds, as well as studying how dust can affect a planet’s climate and environment overall.

• Bottom line: Atmospheric dust could increase the habitability of some exoplanets.
• Source: Mineral dust increases the habitability of terrestrial planets but confounds biomarker detection
• Via University of Exeter

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02-07-2020 om 01:27 geschreven door peter