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Showing posts with label black hole. Show all posts
Showing posts with label black hole. Show all posts

Saturday 31 January 2015

A NEAR-COLLISION STRETCHED THIS GALAXY LIKE A "TAFFY PULL"

Hubble image of NGC 7714 Two galaxies drifted too close together between 100 and 200 million years ago, and began to drag at and disrupt one another’s structure and shape 

At first glance,it looks like a giant rollercoaster loop.
However, this incredible image actually shows a ‘river’ of Sun-like stars that has been pulled deep into space by the gravitational tug of a bypassing galaxy
The golden loop is made of sun-like stars that have been pulled deep into space, far from the galaxy’s centre.
Experts say the galaxy, called NGC 7714, has witnessed some violent and dramatic events in its recent past.
Tell-tale signs of this brutality can be seen in NGC 7714’s strangely shaped arms, and in the smoky golden haze that stretches out from the galactic centre, they say.
The culprit is a smaller companion named NGC 7715, which lies just out of the frame of this image.
As a result, a ring and two long tails of stars have emerged from NGC 7714, creating a bridge between the two galaxies. This bridge acts as a pipeline, funnelling material from NGC 7715 towards its larger companion and feeding bursts of star formation. Most of the star-forming activity is concentrated at the bright galactic centre, although the whole galaxy is sparking new stars.
The galaxy is located approximately 100 million light-years from Earth in the direction of the constellation Pisces.
Astronomer believe that our Galaxy will also collide with its companion galaxy Andromeda after 4 billion years . Here is the Simulation of Galactic collision
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Source : Dailymail , io9

Monday 26 January 2015

Wormhole to another galaxy may exist in Milky Way



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(Click Image to Download)

A giant doorway to another galaxy may exist at the centre of the Milky Way, a study suggests.




Scientists believe that dark matter at the centre of our galaxy could sustain a wormhole that we could travel through.




Wormholes are areas where space and time are being bent so that distant points are now closer together.




Einstein predicted them in his theory of General Relativity but nobody knows how they could be held open so that someone could travel through. Most scientists believe that It is extremely unlikely they could exist naturally in the universe. It would take a huge mass, like a Neutron star, to create a bend in time which could bend space time enough to meet another tunnel on the other side. No natural examples have ever been detected.

"If we combine the map of the dark matter in the Milky Way with the most recent Big Bang model to explain the universe and we hypothesise the existence of space-time tunnels, what we get is that our galaxy could really contain one of these tunnels, and that the tunnel could even be the size of the galaxy itself," said Professor Paulo Salucci.

"But there's more. We could even travel through this tunnel, since, based on our calculations, it could be navigable. Just like the one we've all seen in the recent film 'Interstellar"'.

He said the research was surprisingly close to what was depicted in director Christopher Nolan's movie, for which theoretical physicist Kip Thorne provided technical assistance.

"What we tried to do in our study was to solve the very equation that the astrophysicist 'Murph' was working on," said Prof Salucci. "Clearly we did it long before the film came out."

Wormhole, conceptual artwork

 Wormholes bend space-time to allow distant regions to meet


Any wormholes existing in nature have previously been assumed to be microscopic pinpricks in the fabric of space-time.

But the one possibly lying at the centre of the Milky Way would be large enough to swallow up a spaceship and its crew.

Prof Salucci added: "Obviously we're not claiming that our galaxy is definitely a wormhole, but simply that, according to theoretical models, this hypothesis is a possibility."

Other "spiral" galaxies similar to the Milky Way - like its neighbour Andromeda - may also contain wormholes, the scientists believe.

Theoretically it might be possible to test the idea by comparing the Milky Way with a different type of nearby galaxy, such as one of the irregular Magellanic Clouds.

In their paper, the scientists write: "Our result is very important because it confirms the possible existence of wormholes in most of the spiral galaxies ..

"Dark matter may supply the fuel for constructing and sustaining a wormhole. Hence, wormholes could be found in nature and our study may encourage scientists to seek observational evidence for wormholes in the galactic halo region."

The theory was published in the journal Annals of Physics.

Source : Telegraph

Wednesday 5 November 2014

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.



Sgra_gas

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


Monday 3 November 2014

Success in the search for quiet, distant quasars

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If quasars weren’t so luminous, we couldn’t see them so far away in space and time. But how about modest quasars, also far away? Astronomers say they’ve found some.

Astronomers at the Institute of Astrophysics of Andalusia (IAA-CSIC) in Spain say they have at last discovered a population of quiet, distant quasars. Nearly all the quasars we see at great distances are ultraluminous, and no wonder. They must be extremely luminous in order for us to glimpse them over the vastness of space. And yet astronomers have thought there must be, at those same vast distances, some quasars that were relatively quiet. Now, they say, they’ve found some and have been able to compare them both with the ultraluminous quasars in the early universe and also with closer quasars of moderate luminosity.

The farther away we look in space, the deeper we are looking into the past. Thus the ultraluminous quasars at great distances are showing us events taking place in the early universe: mergers of great galaxies containing gigantic black holes, with masses equivalent to billions of our suns, at their cores. These objects and events in the young universe are what we see as the distant quasars. The question has been, do the distant, tremendously high energy quasars have local relatives, in their same region of space and time, with much lower energy? And are those quiet quasars at great distances the dying versions of formerly ultraluminous quasars? Or are they something else entirely?

Jack W. Sulentic, astronomer at the Institute of Astrophysics of Andalusia (IAA-CSIC), who is leading the research, said:
Astronomers have always wanted to compare past and present, but it has been almost impossible because at great distances we can only see the brightest objects and nearby such objects no longer exist.

Until now we have compared very luminous distant quasars with weaker ones close by, which is tantamount to comparing household light bulbs with the lights in a football stadium.

Now, these astronomers say, they have detected the first distant, quiet quasars.

They say they employed the light-gathering power of the Gran Telescopio Canarias – known as GranTeCan or GTC telescope – located on the island of La Palma, in the Canary Islands in Spain. This telescope let Sulentic and his team obtain the first spectroscopic data from distant, low luminosity quasars similar to typical nearby ones.

They say their data are reliable enough to let them establish essential parameters of the quiet, distance quasars such as their chemical composition, and the mass of the central black hole or rate at which it absorbs surrounding gas and dust.

Quasars appear to evolve with distance. That is, the farther away they are in space, the brighter they are. This could indicate that quasars extinguish over time. Or it could be the result of anobservational bias masking a different reality: that gigantic quasars evolving very quickly, most of them already extinct, coexist with a quiet population that evolves more slowly, but which our technological limitations have not allowed astronomers to study. Ascensión del Olmo, another IAA-CSIC researcher who took part in this study, said:
We have been able to confirm that, indeed, apart from the highly energetic and rapidly evolving quasars, there is another population that evolves slowly. This population of quasars appears to follow the quasar main sequence … There does not even seem to be a strong relation between this type of quasars, which we see in our environment and those ‘monsters’ that started to glow more than 10 billion years ago.

Are there also differences between distant, quiet quasars and the moderate quasars closer to us in space? These astronomers say there are, and these differences are not surprising. Jack W. Sulentic said:
The local quasars present a higher proportion of heavy elements such as aluminum, iron or magnesium, than the distant relatives, which most likely reflects enrichment by the birth and death of successive generations of stars.

Bottom line: Astronomers in Spain have been able to identify a population of quiet quasars located in the distant universe, that is, in the early universe. They have compared them both to ultraluminous quasars in the early universe and also to quasars closer to us in space and time … and found differences in both cases.

Source : earth sky

Sunday 2 November 2014

'Interstellar' Black Hole is Best Black Hole in Sci-Fi

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Christopher Nolan’s movie ‘Interstellar’ will be an epic space adventure encapsulating humanity’s need to explore the Universe, but it’s the visual effects for the movie that are garnering early attention.

By combining the help of one of the world’s leading black hole physicists with a cutting-edge visual effects (VFX) team, ‘Interstellar’ will depict the most scientifically accurate black hole in science fiction history. And, during production, some new discoveries were made as to how a black hole would appear if we could view it up close.

“Neither wormholes or black holes have been depicted in any Hollywood movie in the way they actually would appear,” said Caltech physicist Kip Thorne in a behind-the-scenes video released by Paramount Pictures (featured below). “This is the first time that the depiction (of a black hole) began with Einstein’s general relativity equations.”

General relativity describes the nature of gravity. How a black hole, being the most gravitationally dominant object in the known Cosmos, would look to an observer can therefore be described by Einstein’s equations — except for when tangling with the Black Hole Information Paradox, then you’ll need some quantum equations to boot.

Thorne is a lifelong friend of fellow black hole guru Stephen Hawking and between both of the theoretical physicists, our modern understanding of how these singularities work has flourished. So with the help of Thorne, Nolan has done something very smart; he’s been able to provide the movie-viewing public with a rare sci-fi look into the actual science of a black hole while maintaining an artistic representation that we can easily comprehend.

Interstellar Movie Trailer #3

http://www.youtube.com/watch?v=ePbKGoIGAXY

Warped Spacetime

While crunching the mathematics and arriving at graphical representations of Einstein’s famous equations, Thorne and the movie’s VFX team realized that if a star is positioned behind the black hole, the starlight may become trapped in the warped spacetime close to the black hole’s event horizon. Known as gravitational lensing, this spacetime effect can be used by astronomers to detect exoplanets, for example. But during the production of ‘Interstellar,’ the team realized a spacetime subtlety.



The Matter of an Accretion Disk

Of course, no black hole would be complete without the addition of a radiating accretion disk. But how would that appear on film?

As matter falls toward the spinning black hole’s event horizon, the gas collects into a hot accretion disk, shining brilliantly. By adding the disk, “we found that if you then render this whole thing and you visualize it all through this extraordinary gravitational lens, the gravity twists this glowing disk of gas into weird shapes and you get this extraordinary ‘rainbow of fire’ across the top of the black hole,” said Franklin.

Science fiction movies are produced to entertain, first and foremost. But as computer graphics become more sophisticated and the science fiction-viewing public becomes more savvy, there is a growing motivation by filmmakers to make space phenomena as ‘real’ as possible. And often that will mean employing the help of scientists to make our most extreme space fantasies as scientifically accurate as possible to maintain a credible storyline.

‘Interstellar’ is shaping up to be one of those rare movies that will combine science and fiction, exciting the viewing public, potentially engaging us with astrophysics in a way we’ve never experienced before.

Source : Discovery News

Thursday 30 October 2014

Finnish researchers discover new type of black hole

Researchers at the University of Turku, in cooperation with international colleagues, have identified a new type of low-mass black hole. The type now discovered is a bright celestial object that emits x-rays.
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NOTE : It is not possible to directly observe a black hole, but it is possible to detect events in its vicinity. An artist's concept of x-ray emissions from a black hole, published by NASA, August 2014

This new type of black hole has less mass than other known types and is associated with x-ray emitting quasars.

Up until now, it has been assumed that the collapse of a massive star generally forms a massive black hole or a small neutron star. The mass gap between neutron stars and stellar mass black holes is a question that has been a matter of inquiry for numerous research teams.

The object now discovered and designed SWIFT J1753.5-0127 has a mass somewhere between that of a conventionally-recognized black hole and a neutron star. Previously, observed neutron stars have been found to have less than two solar masses, while black holes have over five.

Observations related to this new type of low-mass black hole were published in a paper by a group of reseachers at the University of Turku, the Osservatorio Astronomico di Padova, the Max-Planck-Institut für Astronomie, and the INAF-IASF Milan branch, and published by the Monthly Notices of the Royal Astronomical Society.

Source : yle

Saturday 21 September 2013

Black hole might have started the universe- says big bang alternative

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An artistic impression of a black hole


We’re all familiar with the Big Bang theory, the one that states that the universe exploded out of a single, dense point. But there’s a major question tied up in the Big Bang that the known laws of physics can’t explain: what was the nothing that came before everything? Some cosmologists have taken this unknown start to the universe in a different direction and suggested a brand new model for our universe. Instead of a Big Bang, our universe was formed from debris ejected when a four-dimensional star collapsed into a black hole.

The Big Bang, which surfaced in the late 1920s in the work of physicist Georges LeMaître and received a big boost in the 1960s through measurements of the cosmic microwave background, does offer explanations to some of the phenomena we see in the cosmos. Namely the fact that space is expanding. But it leaves other questions unanswered. The Big Bang doesn’t explain why such a violent event could have yielded a universe so uniform in temperature. The most common explanation is that some unknown energy made the young universe expand faster than the speed of light, which would have allowed a small patch with a uniform temperature to stretch out and that’s the cosmos we live in and see.

But the main problem with the Big Bang model is that nothing can explain what happened the moment that single point went bang, which leaves explanations about a uniform temperature largely in the realm of speculation. As Niayesh Afshordi, an astrophysicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, puts it, “For all physicists know, dragons could have come flying out of the singularity.”

But an entirely different model might solve all these problems. With this question in mind, Afshordi and his colleagues turned to a 2000 study that states the three-dimensional universe is a membrane that floats through a ‘bulk universe’ made of four spatial dimensions.