Astronomers Find Rare 5-Star System


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An illustration of two contacting stars — part of the newly discovered bizarre five-star system.

Scientists have discovered an absolutely bizarre star system about 250 light years away, in the constellation Ursa Major.

The system (officially known as 1SWASP J093010.78+533859.5) features five stars that are all gravitationally bound together. Two orbit each other in what’s called a contact eclipsing binary, meaning they’re so close together that they actually share an atmosphere, with gases flowing between them.

Another two stars also orbit each other, but at a much greater distance — about 1.8 million miles, which is more than twice the diameter of the sun. Another star hangs out near that pair, but doesn’t appear to orbit them.

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Systems that include five stars gravitationally bound together are rare, though not unprecedented (astronomers have actually found systems that include as many as six stars). But this is the first one ever found that includes multiple pairs of stars orbiting each other.

The discoverers of the strange system — a team of astronomers from Open University in the UK and elsewhere — presented all these discoveries in a new paper published in the journal Astronomy & Astrophysics. Thanks to George Dvorsky at io9 for bringing it to our attention.

Source: vox.com

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Our star is five billion years younger than most in the Milky Way


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Our sun is nearly 4.5 billion years — which means it missed the charming initial years of the Milky Way galaxy. If you were standing on a planet nearly about 10 billion years ago, when the Milky Way was pretty young, the night sky would have appeared very different. The image below is an artist’s impression of the night sky on a planet in a relatively young Milky Way-type galaxy, the way our galaxy was 10 billion years ago. You can see “the sky are ablaze with star birth. Pink clouds of gas harbor newborn stars, and bluish-white, young star clusters litter the landscape,” as NASA explains.

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Image Credit: NASA/ESA/Z. Levay (STScI)

A recent study of young galaxies like our own demonstrates that as these galaxies slow down creating stars, they also stop developing as quickly in general. Which is quite logical. NASA explains:

“Astronomers don’t have baby pictures of our Milky Way’s formative years to trace the history of stellar growth so they studied galaxies similar in mass to our Milky Way, found in deep surveys of the universe. The farther into the universe astronomers look, the further back in time they are seeing, because starlight from long ago is just arriving at Earth now. From those surveys, stretching back in time more than 10 billion years, researchers assembled an album of images containing nearly 2,000 snapshots of Milky Way-like galaxies. The new census provides the most complete picture yet of how galaxies like the Milky Way grew over the past 10 billion years into today’s majestic spiral galaxies. The multi-wavelength study spans ultraviolet to far-infrared light, combining observations from NASA’s Hubble and Spitzer space telescopes, the European Space Agency’s Herschel Space Observatory, and ground-based telescopes, including the Magellan Baade Telescope at the Las Campanas Observatory in Chile.”

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Above is a selection of Hubble Space Telescope photos, displaying how galaxies similar to our own developed over time.

Source : Physics-astronomy

Hubble Space Telescope Views Globular Cluster Messier 22


The crammed centre of Messier 22

This newly released Hubble image shows Messier 22, the brightest globular cluster visible from the northern hemisphere.

A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers.

Messier 22 is located in the constellation Sagittarius, approximately 10,400 light-years away.

It was the first globular cluster to be discovered. German astronomer Johann Abraham Ihle found it on August 26, 1665, while observing Saturn.

The cluster, also known as M22 or NGC 6656, has a diameter of about 70 light-years and half a million solar masses.

According to astronomers, Messier 22 orbits the galactic center once every 200 million years.

The cluster is an easy object for the naked eye to see. Despite its relative proximity to us, the light from the cluster’s stars is not as bright as it should be as it is dimmed by dust and gas located between us and Messier 22.

As they are leftovers from the early Universe, globular clusters are popular study objects for astronomers.

Messier 22 has fascinating additional features: six planet-sized objects that are not orbiting a star have been detected in the cluster; it seems to host two black holes.

The cluster is one of only three ever found to host a planetary nebula – a short-lived gaseous shells ejected by massive stars at the ends of their lives.

Source : Sci-news

Forget dark matter, STRANGE matter could be lurking somewhere in the universe


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  • Scientists at the National Institute for Space Research in Brazil say an undiscovered type of matter could be found in neutron stars
  • Here matter is so dense that it could be ‘squashed’ into strange matter
  • This would create an entire ‘strange star’ – unlike anything we have seen
  • However, the exact properties of strange matter are unknown
  • If it exists, though, it could help scientists discover ripples in space-time known as gravitational waves

Neutron stars are among the densest objects in the universe – just a spoonful of matter from one of them would weigh more than the moon.

But inside these remarkable stellar objects, which are no bigger than a city on Earth, a remarkable process might be taking place.

Scientists have revealed their matter might become so squashed that it turns into ‘strange matter’ – and observing so-called strange stars could unlock some of the secrets of the universe.

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Scientists at the National Institute for Space Research in Brazil say an undiscovered type of matter could be found in neutron stars (illustration shown). Here matter is so dense that it could be ‘squashed’ into strange matter. This would create an entire ‘strange star’ – unlike anything we have seen

The latest theory was proposed by Dr Pedro Moraes and Dr Oswaldo Miranda, both of the National Institute for Space Research in Brazil.

They say that some types of neutron stars might be made of a new type of matter called strange matter.

What the properties of this matter would be, though, are unknown – but it would likely be a ‘liquid’ of several types of sub-atomic particles.

Source: daily mail

‘Perfect Storm’ Suffocating Star Formation around a Supermassive Black Hole


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High-energy jets powered by supermassive black holes can blast away a galaxy’s star-forming fuel — resulting in so-called “red and dead” galaxies: those brimming with ancient red stars yet little or no hydrogen gas available to create new ones.

Now astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered that black holes don’t have to be nearly so powerful to shut down star formation. By observing the dust and gas at the center NGC 1266, a nearby lenticular galaxy with a relatively modest central black hole, the astronomers have detected a “perfect storm” of turbulence that is squelching star formation in a region that would otherwise be an ideal star factory.

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Fig 1. Artist impression of the central region of NGC 1266. The jets from the central black hole are creating turbulence in the surrounding molecular gas, suppressing star formation in an otherwise ideal environment to form new stars. Credit: B. Saxton (NRAO/AUI/NSF)

This turbulence is stirred up by jets from the galaxy’s central black hole slamming into an incredibly dense envelope of gas. This dense region, which may be the result of a recent merger with another smaller galaxy, blocks nearly 98 percent of material propelled by the jets from escaping the galactic center.

“Like an unstoppable force meeting an immovable object, the molecules in these jets meet so much resistance when they hit the surrounding dense gas that they are almost completely stopped in their tracks,” said Katherine Alatalo, an astronomer with the California Institute of Technology in Pasadena and lead author on a paper published in the Astrophysical Journal. This energetic collision produces powerful turbulence in the surrounding gas, disrupting the first critical stage of star formation. “So what we see is the most intense suppression of star formation ever observed,” noted Alatalo.

Previous observations of NGC 1266 revealed a broad outflow of gas from the galactic center traveling up to 400 kilometers per second. Alatalo and her colleagues estimate that this outflow is as forceful as the simultaneous supernova explosion of 10,000 stars. The jets, though powerful enough to stir the gas, are not powerful enough to give it the velocity it needs to escape from the system.

Continue reading ‘Perfect Storm’ Suffocating Star Formation around a Supermassive Black Hole

The Fastest Stars in the Universe May Approach Light Speed


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Our sun orbits the Milky Way’s center at an impressive 450,000 mph. Recently, scientists have discovered stars hurtling out of our galaxy at a couple million miles per hour. Could there be stars moving even faster somewhere out there?

After doing some calculations, Harvard University astrophysicists Avi Loeb and James Guillochon realized that yes, stars could go faster. Much faster. According to their analysis, which they describe in two papers recently posted online, stars can approach light speed. The results are theoretical, so no one will know definitively if this happens until astronomers detect such stellar speedsters—which, Loeb says, will be possible using next-generation telescopes.

But it’s not just speed these astronomers are after. If these superfast stars are found, they could help astronomers understand the evolution of the universe. In particular, they give scientists another tool to measure how fast the cosmos is expanding. Moreover, Loeb says, if the conditions are right, planets could orbit the stars, tagging along for an intergalactic ride. And if those planets happen to have life, he speculates, such stars could be a way to carry life from one galaxy to another.

It all started in 2005 when a star was discovered speeding away from our galaxyfast enough to escape the gravitational grasp of the Milky Way. Over the next few years, astronomers would find several more of what became known as hypervelocity stars. Such stars were cast out by the supermassive black hole at the center of the Milky Way. When a pair of stars orbiting each other gets close to the central black hole, which weighs about four million times as much as the sun, the three objects engage in a brief gravitational dance that ejects one of the stars. The other remains in orbit around the black hole.

Loeb and Guillochon realized that if instead you had two supermassive black holes on the verge of colliding, with a star orbiting around one of the black holes, the gravitational interactions could catapult the star into intergalactic space at speeds reaching hundreds of times those of hypervelocity stars.

This appears to be the most likely scenario that would produce the fastest stars in the universe, Loeb says. After all, supermassive black holes collide more often than you might think. Nearly all galaxies have supermassive black holes at their centers, and nearly all galaxies were the product of two smaller galaxies merging. When galaxies combine, so do their central black holes.

Loeb and Guillochon calculated that merging supermassive black holes would eject stars at a wide range of speeds. Only some would reach near light speed, but many of the rest would still be plenty fast. For example, Loeb says, the observable universe could have more than a trillion stars moving at a tenth of light speed, about 67 million miles per hour.

Because a single, isolated star streaking through intergalactic space would be so faint, only powerful future telescopes like the James Webb Space Telescope , planned for launch in 2018, would be able to detect them. Even then, telescopes would likely only see the stars that have reached our galactic neighborhood. Many of the ejected stars probably would have formed near the centers of their galaxies, and would have been thrown out soon after their birth. That means that they would have been traveling for the vast majority of their lifetimes. The star’s age could therefore approximate how long the star has been traveling. Combining travel time with its measured speed, astronomers can determine the distance between the star’s home galaxy and our galactic neighborhood.

If astronomers can find stars that were kicked out of the same galaxy at different times, they can use them to measure the distance to that galaxy at different points in the past. By seeing how the distance has changed over time, astronomers can measure how fast the universe is expanding.

These superfast rogue stars could have another use as well. When supermassive black holes smash into each other, they generate ripples in space and time called gravitational waves, which reveal the intimate details of how the black holes coalesced. A space telescope called eLISA, scheduled to launch in 2028, is designed to detect gravitational waves. Because the superfast stars are produced when black holes are just about to merge, they would act as a sort of bat signal pointing eLISA to possible gravitational wave sources.

The existence of these stars would be one of the clearest signals that two supermassive black holes are on the verge of merging, says astrophysicist Enrico Ramirez-Ruiz of the University of California, Santa Cruz. Although they may be hard to detect, he adds, they will provide a completely novel tool for learning about the universe.

In about 4 billion years, our own Milky Way Galaxy will crash into the Andromeda Galaxy. The two supermassive black holes at their centers will merge, and stars could be thrown out. Our own sun is a bit too far from the galaxy’s center to get tossed, but one of the ejected stars might harbor a habitable planet. And if humans are still around, Loeb muses, they could potentially hitch a ride on that planet and travel to another galaxy. Who needs warp drive anyway?

Source : wired.com

Monster Telescope Will be World’s Largest Cosmic Eye


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An artist’s illustration depicts the European Extremely Large Telescope (E-ELT) in its enclosure. It eventually will be the world’s largest “eye on the sky.” (Click Image to Download)

The world’s largest telescope has gotten its official construction go-ahead, keeping the enormous instrument on track to start observing the heavens in 2024.

The European Extremely Large Telescope (E-ELT), which will feature a light-collecting surface 128 feet (39 meters) wide, has been greenlit for construction atop Cerro Armazones in Chile’s Atacama Desert, officials with the European Southern Observatory (ESO) announced Thursday (Dec. 4).

The current construction approval applies only to Phase 1; contracts for this work will be awarded in late 2015. The Phase 2 components will be approved as more funding becomes available, ESO officials said.

“The funds that are now committed will allow the construction of a fully working E-ELT that will be the most powerful of all the extremely large telescope projects currently planned, with superior light-collecting area and instrumentation,” de Zeeuw said. “It will allow the initial characterization of Earth-mass exoplanets, the study of the resolved stellar populations in nearby galaxies as well as ultra-sensitive observations of the deep universe.”

 the Thirty Meter Telescope (TMT) — which, not surprisingly, will boast a light-collecting surface 30 m, or 98 feet, wide — is slated to start observing from Hawaii’s Mauna Kea in 2022. Like E-ELT, TMT’s primary mirror will be composed of hundreds of relatively small segments.

All three megascopes should help researchers tackle some of the biggest questions in astronomy, including the nature of the mysterious dark matter and dark energy that make up most of the universe.

Source : Discovery.com

Half of universe’s stars are orphans with no galaxy


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Celestial orphans are relatively small, less massive, cooler than our sun, expert says

New observations from suborbital rocket launches and an orbiting observatory show that as many as half the stars in the universe may be orphans with no galaxy scientists said on Thursday. They found that the dim light these stars produce from the far reaches of the cosmos equals the amount coming from all the galaxies.

‘The night sky on a planet around such a star would be profoundly boring and black to human eyes – no other stars, or at least very few, no Milky Way band, only distant galaxies.’                                        – Michael Zemcov, Caltech experimental astrophysicist

The phenomenon of the orphan star has been well known. Astronomers have witnessed tidal streams of stars being stripped away from colliding pairs of galaxies.

The data suggests orphan stars are probably relatively small, less massive and cooler than our Sun, but typical of most stars in the universe, said Caltech experimental astrophysicist Michael Zemcov.

The night sky as seen from Earth is brimming with starlight. But these orphans would be so distant from other stars that a view from one would offer almost complete nothingness.

“The night sky on a planet around such a star would be profoundly boring and black to human eyes – no other stars, or at least very few, no Milky Way band, only distant galaxies. You might be lucky and see your parent galaxy off in the distance like we see Andromeda,” Zemcov said.

Zemcov said scientists have traced the origin of galaxies to about 13.2 billion years ago, 500 million years after the Big Bang that created the universe.

“Galaxies have been forming and interacting continuously since then, with a peak in the star formation rate about two billion years after the Big Bang,” Zemcov said. “You have enough interactions over enough time, and you end up stripping out a lot of stars.”

Source : cbc.ca

Milky Way’s Supermassive Black Hole Reveals Identity of Strange Object at Center of Our Galaxy


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 What are Supermassive Black Hole ?

Supermassive black hole (SMBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses. Most—and possibly all—galaxies are inferred to contain a supermassive black hole at their centers.In the case of the Milky Way, the SMBH is believed to correspond with the location of Sagittarius A*.

For years, astronomers have been puzzled by a bizarre object in the center of the Milky Way that was believed to be a hydrogen gas cloud headed toward our galaxy’s enormous black hole. Having studied it during its closest approach to the black hole this summer, UCLA astronomers believe that they have solved the riddle of the object widely known as G2.

A team led by Andrea Ghez, professor of physics and astronomy in the UCLA College, determined that G2 is most likely a pair of binary stars that had been orbiting the black hole in tandem and merged together into an extremely large star, cloaked in gas and dust — its movements choreographed by the black hole’s powerful gravitational field. The research is published today in the journal Astrophysical Journal Letters.
“We are seeing phenomena about black holes that you can’t watch anywhere else in the universe,” Ghez added. “We are starting to understand the physics of black holes in a way that has never been possible before.”

Ghez, who studies thousands of stars in the neighborhood of the supermassive black hole, said G2 appears to be just one of an emerging class of stars near the black hole that are created because the black hole’s powerful gravity drives binary stars to merge into one. She also noted that, in our galaxy, massive stars primarily come in pairs. She says the star suffered an abrasion to its outer layer but otherwise will be fine.

Astronomers had figured that if G2 had been a hydrogen cloud, it could have been torn apart by the black hole, and that the resulting celestial fireworks would have dramatically changed the state of the black hole. “G2 survived and continued happily on its orbit; a simple gas cloud would not have done that,” said Ghez, who holds the Lauren B. Leichtman and Arthur E. Levine Chair in Astrophysics. “G2 was basically unaffected by the black hole. There were no fireworks.”

Black holes, which form out of the collapse of matter, have such high density that nothing can escape their gravitational pull — not even light. They cannot be seen directly, but their influence on nearby stars is visible and provides a signature, said Ghez, a 2008 MacArthur Fellow.

The image below shows Sagittarius A* — the giant black hole at the center of our galaxy — appears dim in this composite image because very little material is falling into it.

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Ghez and her colleagues — who include lead author Gunther Witzel, a UCLA postdoctoral scholar, and Mark Morris and Eric Becklin, both UCLA professors of physics and astronomy — conducted the research at Hawaii’s W.M. Keck Observatory, which houses the world’s two largest optical and infrared telescopes.

When two stars near the black hole merge into one, the star expands for more than 1 million years before it settles back down, said Ghez, who directs the UCLA Galactic Center Group. “This may be happening more than we thought. The stars at the center of the galaxy are massive and mostly binaries. 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 and her colleagues also determined that G2 appears to be in that inflated stage now. The body has fascinated many astronomers in recent years, particularly during the year leading up to its approach to the black hole. “It was one of the most watched events in astronomy in my career,” Ghez said.

Ghez said G2 now is undergoing what she calls a “spaghetti-fication” — a common phenomenon near black holes in which large objects become elongated. At the same time, the gas at G2’s surface is being heated by stars around it, creating an enormous cloud of gas and dust that has shrouded most of the massive star.

Witzel said the researchers wouldn’t have been able to arrive at their conclusions without the Keck’s advanced technology. “It is a result that in its precision was possible only with these incredible tools, the Keck Observatory’s 10-meter telescopes,” Witzel said.

The telescopes use adaptive optics, a powerful technology pioneered in part by Ghez that corrects the distorting effects of the Earth’s atmosphere in real time to more clearly reveal the space around the supermassive black hole. The technique has helped Ghez and her colleagues elucidate many previously unexplained facets of the environments surrounding supermassive black holes.

The image at the top of the page is a simulation showing the possible behavior of a gas cloud that has been observed approaching the black hole at the center of the Milky Way.

Source :  daily galaxy

IF YOU THINK THAT EARTH IS VERY LARGE THEN JUST TAKE A LOOK AT THIS VIDEO