Tag: fast (page 3 of 12)

Why Luke Skywalker’s binary sunset may be real after all






Excerpt from csmonitor.com

Researchers have found Jupiter-scale gas giants orbiting binary stars and estimate that Earth-like planets orbiting binary stars could be as numerous as rocky planets orbiting single-star systems.


For all the sci-fi charm of watching a pair of suns sink below a distant horizon on a planet in a galaxy far, far away, conventional wisdom has held that binary-star systems can't host Earth-scale rocky planets.

As the two stars orbit each other like square-dance partners swinging arm in arm, regular variations in their gravitational tug would disrupt planet formation at the relatively close distances where rocky planets tend to appear.

Not so fast, say two astrophysicists. They argue that only are Tatooine-like planets likely to be out there. They could be as numerous as rocky planets orbiting single-star systems – which is to say, there could be large number of them.

Building rocky planets in a binary system not only is possible, it's "not even that hard," says Scott Kenyon, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who along with University of Utah astrophysicist Benjamin Bromley performed the calculations.
Researchers have found Jupiter-scale gas giants orbiting binary stars and have estimated that such gas giants are likely to be as common in binary systems as they are in systems with a single star.
"If that's true, then Earth-like planets around binaries are just as common as Earth-like planets around single stars," Dr. Kenyon says. "If they're not common, that tells you something about how they form or how they interact with the star over billions of years."

The modeling study grew out of work the two researchers were undertaking to figure out how the dwarf planet Pluto and its largest moon Charon manage to share space with four smaller moons that orbit the two larger objects. 

Pluto and Charon form a binary system that early in its history saw the two objects graze each other to generate a ring of dust that would become the additional moons.

The gravity the surrounding dust felt as Pluto and Charon swung about their shared center of mass would vary with clock-like precision.

Conventional wisdom held that this variable tug would trigger collisions at speeds too fast to allow the dust and larger chunks to merge into ever larger objects.

Kenyon and Dr. Bromley found that, in fact, the velocities would be smaller than people thought – no greater than the speeds would be around a single central object, where velocities are slow enough to allow the debris to bump gently and merge to build ever-larger objects.

They recognized that binary stars hosting planets are essentially scaled-up versions of the Pluto-Charon system. So they applied their calculations to a hypothetical binary star system with a circumstellar disk of dust and debris.

"The modest jostling in these orbits is the same modest jostling you'd get around a single star," Kenyon says, allowing rocky inner planets to form.

As for the Jupiter- or Neptune-scale planets found around binary stars, they would have formed farther out and migrated in over time, the researchers say, since there is too little material within the inner reaches of a circumstellar disk to build giant planets.

The duo's calculations imply that as more planets are discovered orbiting binary stars, a rising number of Tatooines will be among them. 

Tatooine "was science fiction," Kenyon says. But "it's not so far from science reality."

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If the Moon Landings Were Real, Then Why is NASA Stumped by This?

Buck Rogers, Staff WriterWaking TimesDuring the cold war era the Soviet Union and the United States were locked in an arms and technology race, each nation wanting to prove their dominance over the other, each striving to be the next reigning superpower in a world still shattered by the second world war. The Soviet’s took the lead when in April of 1961, cosmonaut Yuri Gagarin successfully orbited the earth and returned home safely. In May, president John F. Kennedy ma [...]

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How Quantum Physics will change your life and amaze the world!

 Excerpt from educatinghumanity.com "Anyone not shocked by quantum mechanics has not yet understood it."Niels Bohr10 Ways Quantum Physics Will Change the WorldEver want to have a "life do over", teleport, time travel, have your computer wor...

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Don’t Blame the Devil Anymore: Is Temptation All in Your ‘Syn’ apse?

 I find it very interesting that 'temptation' may lie within the 'syn' - apse. Greg Excerpt from huffingtonpost.comLack of self-control is at the root of many personal and social ills, from alcoholism to obesity. Even when we are well aware ...

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Concorde Comeback? Two New Jets Plan to Take Air Passengers Supersonic Again




Concorde Comeback? Two New Jets Plan to Take Air Passengers Supersonic Again
Lockheed Martin and NASA’s N+2 jet could cut cross-country flight times in half. (Photo: Lockheed Martin)



Excerpt from yahoo.com

Lockheed Martin and NASA’s N+2 jet could cut cross-country flight times in half. New York to Los Angeles in just over two hours? Passenger jets that fly faster than the speed of sound without that annoying sonic boom?  


That could become reality thanks to two projects that aim to bring supersonic planes back to commercial air travel.  Lockheed Martin is working with NASA on a design called the N+2, an 80-passenger jet capable of cruising at Mach 1.7 (1.7 times the speed of sound). 

But what about that loud sonic boom you get when an airplane exceeds the sound barrier? Lockheed Martin and NASA are working hard to lower the boom, so to speak. They say their proposed new jet will be 100 times quieter than the Concorde, the supersonic passenger jets that flew transatlantic routes from 1969 until they were grounded in 2003.

image
The supersonic Concorde flew from 1969 to 2003. (Photo: AP)


A quieter jet would allow the N+2 to fly at supersonic speeds on cross-country routes as the FAA, concerned about sonic booms going off over sleepy U.S. suburbs, currently bans civilian planes from going all “Danger Zone” in American airspace. Lockheed Martin says their new jet would cut cross-country flight times in half.  Related: Race for the First Windowless Plane Heats Up  A rival supersonic jet development project is underway in Reno, Nevada, where European aircraft maker Airbus is working with American firm Aerion on a new, fuel-efficient plane for business clients. The 12-passenger Aerion AS2 will fly at 1,217 mph (which is almost as fast as the Concorde, which flew at 1,350 mph). That would take you from New York to London in three hours and from Los Angeles to Tokyo in six.  

Since the AS2 would do most of its flying over oceans, its designers aren’t as concerned with loud sonic booms. The AS2’s big innovation is fuel efficiency, with new wings that are said to reduce drag by 20 percent.  The makers of the AS2 plan to deliver their first plane in 2022 while Lockheed Martin hopes to have the N+2 flying in 2025.  

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Archaeologists find two lost cities deep in Honduras jungle


Archaeologists in Honduras have found dozens of artifacts at a site where they believe twin cities stood. Photograph: Dave Yoder/National Geographic
Archaeologists in Honduras have found dozens of artifacts at a site where they believe twin cities stood. Photograph: Dave Yoder/National Geographic
Excerpt from theguardian.com


Archaeological team say they have set foot in a place untouched by humans for at least 600 years in a site that may be the ‘lost city of the monkey god’

Archaeologists have discovered two lost cities in the deep jungle of Honduras, emerging from the forest with evidence of a pyramid, plazas and artifacts that include the effigy of a half-human, half-jaguar spirit.
The team of specialists in archaeology and other fields, escorted by three British bushwhacking guides and a detail of Honduran special forces, explored on foot a remote valley of La Mosquitia where an aerial survey had found signs of ruins in 2012.
Chris Fisher, the lead US archaeologist on the team, told the Guardian that the expedition – co-coordinated by the film-makers Bill Benenson and Steve Elkins, Honduras and National Geographic (which first reported the story on its site) – had by all appearances set foot in a place that had gone untouched by humans for at least 600 years.
“Even the animals acted as if they’ve never seen people,” Fisher said. “Spider monkeys are all over place, and they’d follow us around and throw food at us and hoot and holler and do their thing.”
“To be treated not as a predator but as another primate in their space was for me the most amazing thing about this whole trip,” he said.
Fisher and the team arrived by helicopter to “groundtruth” the data revealed by surveying technology called Lidar, which projects a grid of infrared beams powerful enough to break through the dense forest canopy.
The dense jungle of Honduras. Photograph: Dave Yoder/National Geographic
The dense jungle of Honduras.Photograph: Dave Yoder/National Geographic
That data showed a human-created landscape, Fisher said of sister cities not only with houses, plazas and structures, but also features “much like an English garden, with orchards and house gardens, fields of crops, and roads and paths.”
In the rainforest valley, they said they found stone structural foundations of two cities that mirrored people’s thinking of the Maya region, though these were not Mayan people. The area dates between 1000AD and 1400AD, and while very little is known without excavation of the site and surrounding region, Fisher said it was likely that European diseases had at least in part contributed to the culture’s disappearance.
The expedition also found and documented 52 artifacts that Virgilio Paredes, head of Honduras’s national anthropology and history institute, said indicated a civilisation distinct from the Mayans. Those artifacts included a bowl with an intricate carvings and semi-buried stone sculptures, including several that merged human and animal characteristics.
The cache of artifacts – “very beautiful, very fantastic,” in Fisher’s words – may have been a burial offering, he said, noting the effigies of spirit animals such as vultures and serpents.
Fisher said that while an archaeologist would likely not call these cities evidence of a lost civilisation, he would call it evidence of a culture or society. “Is it lost? Well, we don’t know anything about it,” he said.
The exploratory team did not have a permit to excavate and hopes to do so on a future expedition. “That’s the problem with archaeology is it takes a long time to get things done, another decade if we work intensively there, but then we’ll know a little more,” Fisher said.
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“This wasn’t like some crazy colonial expedition of the last century,” he added.
Despite the abundance of monkeys, far too little is known of the site still to tie it to the “lost city of the monkey god” that one such expedition claimed to have discovered. In about 1940, the eccentric journalist Theodore Morde set off into the Honduran jungle in search of the legendary “white city” that Spanish conquistadors had heard tales of in the centuries before.
He broke out of the brush months later with hundreds of artifacts and extravagant stories of how ancient people worshipped their simian deity. According to Douglas Preston, the writer National Geographic sent along with its own expedition: “He refused to divulge the location out of fear, he said, that the site would be looted. He later committed suicide and his site – if it existed at all – was never identified.”
Fisher emphasised that archaeologists know extraordinarily little about the region’s ancient societies relative to the Maya civilisation, and that it would take more research and excavation. He said that although some academics might find it distasteful, expeditions financed through private means – in this case the film-makers Benenson and Elkins – would become increasingly commonplace as funding from universities and grants lessened.
Fisher also suggested that the Lidar infrared technology used to find the site would soon be as commonplace as radiocarbon dating: “People just have to get through this ‘gee-whiz’ phase and start thinking about what we can do with it.”
Paredes and Fisher also said that the pristine, densely-wooded site was dangerously close to land being deforested for beef farms that sell to fast-food chains. Global demand has driven Honduras’s beef industry, Fisher said, something that he found worrying.
“I keep thinking of those monkeys looking at me not having seen people before. To lose all this over a burger, it’s a really hard pill to swallow.”

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Astronomers find star speeding out of the galaxy





(Reuters) - Astronomers have found a star hurtling through the galaxy faster than any other, the result of being blasted away by the explosion of a massive partner star, researchers said on Thursday.
The star, known as US 708, is traveling at about 746 miles (1,200 km) per second, fast enough to actually leave the Milky Way galaxy in about 25 million years, said astronomer Stephan Geier with Germany-based European Southern Observatory, which operates three telescopes in Chile.

"At that speed you could travel from Earth to the moon in five minutes," noted University of Hawaii astronomer Eugene Magnier.
US 708 is not the first star astronomers have found that is moving fast enough to escape the galaxy, but it is the only one so far that appears to have been slingshot in a supernova explosion.

The 20 other stars discovered so far that are heading out of the galaxy likely got their impetus from coming too close to the supermassive black hole that lives at the center of the Milky Way, scientists report in an article in this week’s edition of the journal Science.

Before it was sent streaming across the galaxy, US 708 was once a cool giant star, but it was stripped of nearly all of its hydrogen by a closely orbiting partner. Scientists suspect it was this feeding that triggered the partner’s detonation.

If confirmed, these types of ejected stars may provide more insight into how supernova explosions occur. Since the explosions give off a fairly standard amount of radiation, scientists can calculate their distances by measuring how bright or dim they appear and determine how fast the universe is expanding.

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Strange find on Titan sparks chatter about life


Titan


Excerpt from nbcnews.com

Studies may suggest methane-based organic processes ... but maybe not  
New findings have roused a great deal of hoopla over the possibility of life on Saturn's moon Titan, which some news reports have further hyped up as hints of extraterrestrials.
However, scientists also caution that aliens might have nothing to do with these findings.

All this excitement is rooted in analyses of chemical data returned by NASA's Cassini spacecraft. One study suggested that hydrogen was flowing down through Titan's atmosphere and disappearing at the surface. Astrobiologist Chris McKay at NASA's Ames Research Center speculated that this could be a tantalizing hint that hydrogen is getting consumed by life.

"It's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," McKay said.

Another study investigating hydrocarbons on Titan's surface found a lack of acetylene, a compound that could be consumed as food by life that relies on liquid methane instead of liquid water to live.
"If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth," McKay said.
However, NASA scientists caution that aliens might not be involved at all.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," said Mark Allen, principal investigator with the NASA Astrobiology Institute Titan team. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results."
McKay told Space.com that "both results are still preliminary."

To date, methane-based life forms are only speculative, with McKay proposing a set of conditions necessary for these kinds of organisms on Titan in 2005. Scientists have not yet detected this form of life anywhere, although there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product. 

On Titan, where temperatures are around minus-290 degrees Fahrenheit (-179 degrees Celsius), any organisms would have to use a substance that is liquid as its medium for living processes. Water itself cannot do, because it is frozen solid on Titan's surface. The list of liquid candidates is very short — liquid methane and related molecules such as ethane. Previous studies have found Titan to have lakes of liquid methane.

Missing hydrogen? 

The dearth of hydrogen Cassini detected is consistent with conditions that could produce methane-based life, but do not conclusively prove its existence, cautioned researcher Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore. Strobel wrote the paper on hydrogen appearing online in the journal Icarus.


Strobel looked at densities of hydrogen in different parts of the atmosphere and at the surface. Previous models from scientists had predicted that hydrogen molecules, a byproduct of ultraviolet sunlight breaking apart acetylene and methane molecules in the upper atmosphere, should be distributed fairly evenly throughout the atmospheric layers.

Strobel's computer simulations suggest a hydrogen flow down to the surface at a rate of about 10,000 trillion trillion molecules per second. 

"It's as if you have a hose and you're squirting hydrogen onto the ground, but it's disappearing," Strobel said. "I didn't expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should 'float' to the top of the atmosphere and escape."

Strobel said it is not likely that hydrogen is being stored in a cave or underground space on Titan. An unknown mineral could be acting as a catalyst on Titan's surface to help convert hydrogen molecules and acetylene back to methane.

Although Allen commended Strobel, he noted "a more sophisticated model might be needed to look into what the flow of hydrogen is."

Consumed acetylene? 

Scientists had expected the sun's interactions with chemicals in the atmosphere to produce acetylene that falls down to coat Titan's surface. But when Cassini mapped hydrocarbons on Titan's surface, it detected no acetylene on the surface, according to findings appearing online in the Journal of Geophysical Research.


Instead of alien life on Titan, Allen said one possibility is that sunlight or cosmic rays are transforming the acetylene in icy aerosols in the atmosphere into more complex molecules that would fall to the ground with no acetylene signature.

In addition, Cassini detected an absence of water ice on Titan's surface, but loads of benzene and another as-yet-unidentified material, which appears to be an organic compound. The researchers said that a film of organic compounds is covering the water ice that makes up Titan's bedrock. This layer of hydrocarbons is at least a few millimeters to centimeters thick, but possibly much deeper in some places. 

"Titan's atmospheric chemistry is cranking out organic compounds that rain down on the surface so fast that even as streams of liquid methane and ethane at the surface wash the organics off, the ice gets quickly covered again," said Roger Clark, a Cassini team scientist based at the U.S. Geological Survey in Denver. "All that implies Titan is a dynamic place where organic chemistry is happening now."

All this speculation "is jumping the gun, in my opinion," Allen said.

"Typically in the search for the existence of life, one looks for the presence of evidence -- say, the methane seen in the atmosphere of Mars, which can't be made by normal photochemical processes," Allen added. "Here we're talking about absence of evidence rather than presence of evidence — missing hydrogen and acetylene — and oftentimes there are many non-life processes that can explain why things are missing."

These findings are "still a long way from evidence of life," McKay said. "But it could be interesting."

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Rare doomed planet with extreme seasons discovered


Kepler432b.jpg
Illustration provided by the University of Heidelberg of the orbit of Kepler-432b (inner, red) in comparison to the orbit of Mercury around the Sun (outer, orange). The red dot in the middle indicates the position of the star around which the planet is orbiting. The size of the star is shown to scale, while the size of the planet has been magnified ten times for illustration purposes. (Graphic: Dr. Sabine Reffert)


Excerpt from foxnews.com/science


A rare planet has been discovered, and it doesn’t seem like a stop anyone would want to make on an intergalactic cruise. Found by two research teams independently of each other, Kepler-432b is extreme in its mass, density, and weather. Roughly the same size of Jupiter, the planet is also doomed- in 200 million years it will be consumed by its sun. “Kepler-432b is definitively a rarity among exoplanets around giant stars: it is a close-in gas-giant planet orbiting a star whose radius is 'quickly' increasing,” Davide Gandolfi, from the Landessternwarte Koenigstuhl (part of the Centre for Astronomy of the University of Heidelberg), told FoxNews.com. “The orbit of the planet has a radius of about 45 million kilometers [28 million miles] (as a reference point, the Earth-Sun distance is about 150 million kilometers [93.2 Million miles]), while most of the planets known to orbit giant stars have wider orbits. The stellar radius is already 3 million kilometers [almost 2 million miles] (i.e., about 4 times the Sun radius) and in less than 200 million years it will be large enough for the star to swallow up its planet.”

Gandolfi, a member of one of the research groups who discovered the rare planet, explains that much like Jupiter, Kepler-432b is a gas-giant celestial body composed mostly of hydrogen and helium, and is most likely to have a dense core that accounts for 6 percent or less of the planet’s mass. “The planet has a mass six times that of Jupiter, but is about the same size!” he says. “This means that it is not one of the largest planets yet discovered: it is one of the most massive!” The planet’s orbit brings it extremely close to its host star on some occasions, and very far away at others, which creates extreme seasonal changes. In its year - which lasts 52 Earth days - winters can get a little chilly and summers a bit balmy, to say the least. According to Gandolfi, “The highly eccentric orbit brings Kepler-432b at ‘only’ 24 million kilometers [15 million miles] from its host star, before taking it to about three times as far away. This creates large temperature excursions over the course of the planet year, which is of only 52 Earth days. During the winter season, the temperature on Kepler-432b drops down to 500 degrees Celsius [932 degrees Fahrenheit], whereas in summer it can goes up to nearly 1000 degrees Celsius [1832 degrees Fahrenheit].”

Then again, if you are crazy enough to visit Kepler-432b, you’d better do it fast. As stated before, its host star is set to swallow the planet whole in 200 million years, making the celestial body a rare find. “The paucity of close-in planets around giant stars is likely to be due to the fact that these planets have been already swallowed up by their host stars,” Gandolfi says. “Kepler-432b has been discovered ‘just in time before dinner!” The host star, which is red and possesses 1.35 times the mass of our sun, has partly exhausted the nuclear fuel in its core, and is slowly expanding, eventually growing large enough to swallow Kepler-432b. According to Gandolfi, this is a natural progression for all stars. “Stars first generate nuclear energy in their core via the fusion of Hydrogen into Helium,” he explained. “At this stage, their radii basically do not change much. This is because the outward thermal pressure produced by the nuclear fusion in the core is balanced by the inward pressure of gravitational collapse from the overlying layers. In other words, the nuclear power is the star pillar! Our Sun is currently ‘burning’ hydrogen in its core (please note that I used quotes: ‘burning’ does not mean a chemical reaction- we are talking about nuclear fusion reaction). However, this equilibrium between the two pressures does not last forever. Helium is heavier than hydrogen and tends to sink. The stellar core of the Kepler-432b's host star is currently depleted of hydrogen and it is mainly made of inert helium. The star generates thermal energy in a shell around the core through the nuclear fusion of hydrogen into helium. As a result of this, the star expands and cools down. This is why we call it ‘red giant’- the reddish color comes from the fact that the external layers of the atmosphere of the star are cooling down because they expand.”

Both research teams (the other was from the Max Planck Institute for Astronomy in Heidelberg) used Calar Alto Observatory’s 7.2- foot telescope in Andalucia, Spain. The planet was also studied by Landessternwarte Koenigstuhl researchers using the 8.5-foot Nordic Optical Telescope on La Palma, which is located in Spain’s Canary Islands.

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Cluster Filled with Dark Matter May House ‘Failed Galaxies’

The Coma Cluster


Excerpt space.com

A strange set of 48 galaxies appears to be rich in dark matter and lacking in stars, suggesting that they may be so-called "failed" galaxies, a new study reports.

The galaxies in question are part of the Coma Cluster, which lies 300 million light-years from Earth and packs several thousand galaxies into a space just 20 million light-years across. To study them, Pieter van Dokkum of Yale University and his colleagues used the Dragonfly Telephoto Array in New Mexico.

The array's eight connected Canon telephoto lenses allow the researchers to search for extremely faint objects that traditional telescope surveys miss. Often, such as when the researchers used the array to search for the faint glow that dark matter might create, the hunt comes up empty. 


But when van Dokkum and his colleagues looked toward the Coma Cluster, they found a pleasant surprise.

"We noticed all these faint little smudges in the images from the Dragonfly telescope," van Dokkum told Space.com.

The mysterious blobs nagged at van Dokkum, compelling him to look into the objects further. Fortuitously, NASA's Hubble Space Telescope had recently captured one of these objects with its sharp eye. 

"It turned out that they're these fuzzy blobs that look somewhat like dwarf spheroidal galaxies around our own Milky Way," van Dokkum said. "So they looked familiar in some sense … except that if they are at the distance of the Coma Cluster, they must be really huge."

And with very few stars to account for the mass in these galaxies, they must contain huge amounts of dark matter, the researchers said. In fact, to stay intact, the 48 galaxies must contain 98 percent dark matter and just 2 percent "normal" matter that we can see. The fraction of dark matter in the universe as a whole is thought to be around 83 percent. 

But before making this claim, the team had to verify that these blobs really are as distant as the Coma Cluster. (In fact, the team initially thought the galaxies were much closer.). But even in the Hubble image the stars were not resolved. If Hubble — one of the most powerful telescopes in existence — can't resolve the stars, those pinpricks of light must be pretty far away, study team members reasoned. 

Now, van Dokkum and his colleagues have definitive evidence: They've determined the exact distance to one of the galaxies. The team used the Keck Telescope in Hawaii to look at one of the objects for two hours. This gave them a hazy spectrum, from which they were able to tease out the galaxy's recessional velocity — that is, how fast it is moving away from Earth.

That measure traces back to the Hubble Telescope's namesake. In 1929, American astronomer Edwin Hubble discovered one of the simplest and most surprising relationships in astronomy: The more distant a galaxy, the faster it moves away from the Milky Way.

Today, astronomers use the relationship to measure a galaxy's recessional velocity and thus calculate the galaxy's distance. In this case, the small fuzzy blob observed with Keck was moving away from Earth at 15.7 million mph (25.3 million km/h). That places it at 300 million light-years away from Earth, the distance of the Coma Cluster.

So the verdict is officially in: These galaxies must be associated with the Coma Cluster and therefore must be extremely massive.
"It looks like the universe is able to make unexpected galaxies," van Dokkum said, adding that there is an amazing diversity of massive galaxies.

But the clusters still present a mystery: The team doesn't know why they have so much dark matter and so few stars.

Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma. Test your stellar smarts with this quiz.
One possibility is that these are "failed" galaxies. A galaxy's first supernova explosions will drive away huge amounts of gas. 

Normally, the galaxy has such a strong gravitational pull that most of the expelled gas falls back onto the galaxy and forms the next generations of stars. But maybe the strong gravitational pull of the other galaxies in the Coma Cluster interfered with this process, pulling the gas away.

"If that happened, they had no more fuel for star formation and they were sort of stillborn galaxies where they started to get going but then failed to really build up a lot of stars," said van Dokkum, adding that this is the most likely scenario. 

Another possibility is that these galaxies are in the process of being ripped apart. But astronomers expect that if this were the case, the galaxies would be distorted and streams of stars would be flowing away from them. Because these effects don't appear, this scenario is very unlikely.

The next step is to try to measure the individual motions of stars within the galaxies. If the team knew those stars' speeds, it could calculate the galaxies' exact mass, and therefore the amount of dark matter they contain. If the stars move faster, the galaxy is more massive. And if they move slower, the galaxy is less massive. 
However, this would require a better spectrum than the one the team has right now.

"But it's not outside the realm of what's possible," van Dokkum assured. "It's just very hard."

The original study has been published in Astrophysical Journal Letters. You can read it for free on the preprint site arXiv.org.

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Earth’s Moon May Not Be Critical to Life Afterall




Excerpt from space.com

The moon has long been viewed as a crucial component in creating an environment suitable for the evolution of complex life on Earth, but a number of scientific results in recent years have shown that perhaps our planet doesn't need the moon as much as we have thought.

In 1993, French astronomer Jacques Laskar ran a series of calculations indicating that the gravity of the moon is vital to stabilizing the tilt of our planet. Earth's obliquity, as this tilt is technically known as, has huge repercussions for climate. Laskar argued that should Earth's obliquity wander over hundreds of thousands of years, it would cause environmental chaos by creating a climate too variable for complex life to develop in relative peace.
So his argument goes, we should feel remarkably lucky to have such a large moon on our doorstep, as no other terrestrial planet in our solar system has such a moon. Mars' two satellites, Phobos and Deimos, are tiny, captured asteroids that have little known effect on the Red Planet. Consequently, Mars' tilt wobbles chaotically over timescales of millions of years, with evidence for swings in its rotational axis at least as large as 45 degrees. 


The stroke of good fortune that led to Earth possessing an unlikely moon, specifically the collision 4.5 billion years ago between Earth and a Mars-sized proto-planet that produced the debris from which our Moon formed, has become one of the central tenets of the 'Rare Earth' hypothesis. Famously promoted by Peter Ward and Don Brownlee, it argues that planets where everything is just right for complex life are exceedingly rare.

New findings, however, are tearing up the old rule book. In 2011, a trio of scientists — Jack Lissauer of NASA Ames Research Center, Jason Barnes of the University of Idaho and John Chambers of the Carnegie Institution for Science — published results from new simulations describing what Earth's obliquity would be like without the moon. What they found was surprising.

"We were looking into how obliquity might vary for all sorts of planetary systems," says Lissauer. "To test our code we began with integrations following the obliquity of Mars and found similar results to other people. But when we did the obliquity of Earth we found the variations were much smaller than expected — nowhere near as extreme as previous calculations suggested they would be."
Lissauer's team found that without the moon, Earth's rotational axis would only wobble by 10 degrees more than its present day angle of 23.5 degrees. The reason for such vastly different results to those attained by Jacques Laskar is pure computing power. Today's computers are much faster and capable of more accurate modeling with far more data than computers of the 1990s.

Lissauer and his colleagues also found that if Earth were spinning fast, with one day lasting less than 10 hours, or rotating retrograde (i.e. backwards so that the sun rose in the West and set in the East), then Earth stabilized itself thanks to the gravitational resonances with other planets, most notably giant Jupiter. There would be no need for a large moon. 

Earth's rotation has not always been as leisurely as the current 24 hour spin-rate. Following the impact that formed the moon, Earth was spinning once every four or five hours, but it has since gradually slowed by the moon's presence. As for the length of Earth's day prior to the moon-forming impact, nobody really knows, but some models of the impact developed by Robin Canup of the Southwest Research Institute, in Boulder, Colorado, suggest that Earth could have been rotating fast, or even retrograde, prior to the collision.

Tilted Orbits
Planets with inclined orbits could find that their increased obliquity is beneficial to their long-term climate – as long as they do not have a large moon.


"Collisions in the epoch during which Earth was formed determined its initial rotation," says Lissauer. "For rocky planets, some of the models say most of them will be prograde, but others say comparable numbers of planets will be prograde and retrograde. Certainly, retrograde worlds are not expected to be rare."

The upshot of Lissauer's findings is that the presence of a moon is not the be all and end all as once thought, and a terrestrial planet can exist without a large moon and still retain its habitability. Indeed, it is possible to imagine some circumstances where having a large moon would actually be pretty bad for life.

Rory Barnes, of the University of Washington, has also tackled the problem of obliquity, but from a different perspective. Planets on the edge of habitable zones exist in a precarious position, far enough away from their star that, without a thick, insulating atmosphere, they freeze over, just like Mars. Barnes and his colleagues including John Armstrong of Weber State University, realized that torques from other nearby worlds could cause a planet's inclination to the ecliptic plane to vary. This in turn would result in a change of obliquity; the greater the inclination, the greater the obliquity to the Sun. Barnes and Armstrong saw that this could be a good thing for planets on the edges of habitable zones, allowing heat to be distributed evenly over geological timescales and preventing "Snowball Earth" scenarios. They called these worlds "tilt-a-worlds," but the presence of a large moon would counteract this beneficial obliquity change.

"I think one of the most important points from our tilt-a-world paper is that at the outer edge of the habitable zone, having a large moon is bad, there's no other way to look at it," says Barnes. "If you have a large moon that stabilizes the obliquity then you have a tendency to completely freeze over."

Barnes is impressed with the work of Lissauer's team.
"I think it is a well done study," he says. "It suggests that Earth does not need the moon to have a relatively stable climate. I don't think there would be any dire consequences to not having a moon."

Mars' Changing Tilt
The effects of changing obliquity on Mars’ climate. Mars’ current 25-degree tilt is seen at top left. At top right is a Mars that has a high obliquity, leading to ice gather at its equator while the poles point sunwards. At bottom is Mars with low obliquity, which sees its polar caps grow in size.


Of course, the moon does have a hand in other factors important to life besides planetary obliquity. Tidal pools may have been the point of origin of life on Earth. Although the moon produces the largest tides, the sun also influences tides, so the lack of a large moon is not necessarily a stumbling block. Some animals have also evolved a life cycle based on the cycle of the moon, but that's more happenstance than an essential component for life.

"Those are just minor things," says Lissauer.

Without the absolute need for a moon, astrobiologists seeking life and habitable worlds elsewhere face new opportunities. Maybe Earth, with its giant moon, is actually the oddball amongst habitable planets. Rory Barnes certainly doesn't think we need it.
"It will be a step forward to see the myth that a habitable planet needs a large moon dispelled," he says, to which Lissauer agrees.
Earth without its moon might therefore remain habitable, but we should still cherish its friendly presence. After all, would Beethoven have written the Moonlight Sonata without it?

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Every Black Hole Contains a New Universe


At the center of spiral galaxy M81 is a supermassive black hole about 70 million times more massive than our sun.



Excerpt from insidescience.org
A physicist presents a solution to present-day cosmic mysteries.



By: 
Nikodem Poplawski, Inside Science Minds Guest Columnist



(ISM) -- Our universe may exist inside a black hole. This may sound strange, but it could actually be the best explanation of how the universe began, and what we observe today. It's a theory that has been explored over the past few decades by a small group of physicists including myself. 
Successful as it is, there are notable unsolved questions with the standard big bang theory, which suggests that the universe began as a seemingly impossible "singularity," an infinitely small point containing an infinitely high concentration of matter, expanding in size to what we observe today. The theory of inflation, a super-fast expansion of space proposed in recent decades, fills in many important details, such as why slight lumps in the concentration of matter in the early universe coalesced into large celestial bodies such as galaxies and clusters of galaxies.
But these theories leave major questions unresolved. For example: What started the big bang? What caused inflation to end? What is the source of the mysterious dark energy that is apparently causing the universe to speed up its expansion?
The idea that our universe is entirely contained within a black hole provides answers to these problems and many more. It eliminates the notion of physically impossible singularities in our universe. And it draws upon two central theories in physics.
Nikodem Poplawski displays a "tornado in a tube." The top bottle symbolizes a black hole, the connected necks represent a wormhole and the lower bottle symbolizes the growing universe on the just-formed other side of the wormhole. Credit: Indiana University
In this picture, spins in particles interact with spacetime and endow it with a property called "torsion." To understand torsion, imagine spacetime not as a two-dimensional canvas, but as a flexible, one-dimensional rod. Bending the rod corresponds to curving spacetime, and twisting the rod corresponds to spacetime torsion. If a rod is thin, you can bend it, but it's hard to see if it's twisted or not.

The first is general relativity, the modern theory of gravity. It describes the universe at the largest scales. Any event in the universe occurs as a point in space and time, or spacetime. A massive object such as the Sun distorts or "curves" spacetime, like a bowling ball sitting on a canvas. The Sun's gravitational dent alters the motion of Earth and the other planets orbiting it. The sun's pull of the planets appears to us as the force of gravity.

The second is quantum mechanics, which describes the universe at the smallest scales, such as the level of the atom. However, quantum mechanics and general relativity are currently separate theories; physicists have been striving to combine the two successfully into a single theory of "quantum gravity" to adequately describe important phenomena, including the behavior of subatomic particles in black holes.
A 1960s adaptation of general relativity, called the Einstein-Cartan-Sciama-Kibble theory of gravity, takes into account effects from quantum mechanics. It not only provides a step towards quantum gravity but also leads to an alternative picture of the universe. This variation of general relativity incorporates an important quantum property known as spin. Particles such as atoms and electrons possess spin, or the internal angular momentum that is analogous to a skater spinning on ice.

Spacetime torsion would only be significant, let alone noticeable, in the early universe or in black holes. In these extreme environments, spacetime torsion would manifest itself as a repulsive force that counters the attractive gravitational force coming from spacetime curvature. As in the standard version of general relativity, very massive stars end up collapsing into black holes: regions of space from which nothing, not even light, can escape.
Here is how torsion would play out in the beginning moments of our universe. Initially, the gravitational attraction from curved space would overcome torsion's repulsive forces, serving to collapse matter into smaller regions of space. But eventually torsion would become very strong and prevent matter from compressing into a point of infinite density; matter would reach a state of extremely large but finite density. As energy can be converted into mass, the immensely high gravitational energy in this extremely dense state would cause an intense production of particles, greatly increasing the mass inside the black hole.
The increasing numbers of particles with spin would result in higher levels of spacetime torsion. The repulsive torsion would stop the collapse and would create a "big bounce" like a compressed beach ball that snaps outward. The rapid recoil after such a big bounce could be what has led to our expanding universe. The result of this recoil matches observations of the universe's shape, geometry, and distribution of mass.
In turn, the torsion mechanism suggests an astonishing scenario: every black hole would produce a new, baby universe inside. If that is true, then the first matter in our universe came from somewhere else. So our own universe could be the interior of a black hole existing in another universe. Just as we cannot see what is going on inside black holes in the cosmos, any observers in the parent universe could not see what is going on in ours.
The motion of matter through the black hole's boundary, called an "event horizon," would only happen in one direction, providing a direction of time that we perceive as moving forward. The arrow of time in our universe would therefore be inherited, through torsion, from the parent universe.
Torsion could also explain the observed imbalance between matter and antimatter in the universe. Because of torsion, matter would decay into familiar electrons and quarks, and antimatter would decay into "dark matter," a mysterious invisible form of matter that appears to account for a majority of matter in the universe.
Finally, torsion could be the source of "dark energy," a mysterious form of energy that permeates all of space and increases the rate of expansion of the universe. Geometry with torsion naturally produces a "cosmological constant," a sort of added-on outward force which is the simplest way to explain dark energy. Thus, the observed accelerating expansion of the universe may end up being the strongest evidence for torsion.
Torsion therefore provides a theoretical foundation for a scenario in which the interior of every black hole becomes a new universe. It also appears as a remedy to several major problems of current theory of gravity and cosmology. Physicists still need to combine the Einstein-Cartan-Sciama-Kibble theory fully with quantum mechanics into a quantum theory of gravity. While resolving some major questions, it raises new ones of its own. For example, what do we know about the parent universe and the black hole inside which our own universe resides? How many layers of parent universes would we have? How can we test that our universe lives in a black hole?
The last question can potentially be investigated: since all stars and thus black holes rotate, our universe would have inherited the parent black hole’s axis of rotation as a "preferred direction." There is some recently reported evidence from surveys of over 15,000 galaxies that in one hemisphere of the universe more spiral galaxies are "left-handed", or rotating clockwise, while in the other hemisphere more are "right-handed", or rotating counterclockwise. In any case, I believe that including torsion in geometry of spacetime is a right step towards a successful theory of cosmology.

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Jupiter Wins the Starring Role in February’s Planet Parade

Excerpt from nbc.com Planets are on parade in February's night sky. Giant Jupiter will dazzle all nig...

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