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Posts tagged "black holes"

kenobi-wan-obi:

Could Tiny ‘Black Hole Atoms’ Be Elusive Dark Matter?

Dark matter, the invisible and mysterious stuff that makes up most of the material universe, might be hiding itself in microscopic black holes, says a team of Russian astrophysicists.

No one knows what dark matter is. But scientists do know that it must exist, because there is not enough visible matter in the cosmos to account for all the gravity that binds galaxies and other large-scale structures together.

Astronomers have been on the hunt for dark matter for decades now, using detectors both on Earth and in space. The new hypothesis, formulated by astrophysicists Vyacheslav Dokuchaev and Yury Eroshenko at the Institute for Nuclear Research of the Russian Academy of Sciences in Moscow, suggests that dark matter could be made of microscopic — or quantum — “black hole atoms.”

The concept is not entirely new; others have suggested that various types of miniature black holes could make up dark matter, which is so named because it apparently neither absorbs nor emits light, and thus cannot be detected directly by telescopes.

Physicists have also long believed that microscopic black holes must have existed in the early universe, because quantum fluctuations in the density of matter just after the Big Bang would have created regions of space dense enough to allow the formation of such tiny black holes.

Some researchers believe that the universe could still be full of such “primordial black holes.”

kenobi-wan-obi:

Turbulent Black Holes Grow Fractal Skins As They Feed

Feeding black holes develop a fractal skin as they grow. That’s the conclusion of simulations that take advantage of a correlation between fluid dynamics and gravity.

"We showed that when you throw stuff into a black hole, the surface of the black hole responds like a fluid – and in particular, it can become turbulent," says Allan Adams at the Massachusetts Institute of Technology. "More precisely, the horizon itself becomes a fractal."

Fractals are mathematical sets that show self-similar patterns: zoom in on one part of a fractal drawing, like the famous Mandelbrot set, and the smaller portion will look nearly the same as the original image. Objects with fractal geometries show up all over nature, from clouds to the coast of England.

Adams and his colleagues have now found evidence that fractal behaviour occurs in an unexpected place: on the surface of a feeding black hole. Black holes grow by devouring matter that falls into them; the black hole at the centre of our galaxy is due to feast on a gas cloud later this year. But the details of how feeding black holes grow, and how this might affect their host galaxies, are still unknown.

(via afro-dominicano)

kenobi-wan-obi:

LIGO Lasers Could Help Reveal Aftermath of Black Hole Crashes

A powerful scientific tool set to come online in 2015 could help scientists spot gravitational waves: ripples in space-time born from violent cosmic crashes light-years from Earth.

Image: A still frame from a computer animation shows two binary neutron stars coalescing into a black hole. Taken from the video, “LIGO, A Passion for Understanding,” Credit: Kai Staats

The instrument, called LIGO (short for Laser Interferometer Gravitational-Wave Observatories), uses lasers to hunt for the gravitational aftermath created by two massive objects — like a neutron star and a black hole — colliding. Scientists theorize that, like a rock dropping into a pool of water, the fabric of space and time can ripple, sending out these gravitational waves across the universe at the speed of light. Understanding those waves could help scientists learn more about black holes.

The $205 million LIGO can potentially detect these gravitational waves from Earth. The interconnected LIGO observatories in Washington State and Louisiana make use of two 2.5-mile (4 kilometers) arms. A laser beam is split down the arms that are equipped with specifically placed mirrors. In theory, if a gravitational wave comes into contact with the instrument, it would change the length of one beam in relation to the other.

kenobi-wan-obi:

Hunt Is On for ‘Rogue’ Black Holes

Hundreds of wandering “rogue” black holes may dwell in the Milky Way — and now researchers say they know how to detect them. Discovering these strange objects could shed light on the formation of the Milky Way and other galaxies.

No one knows exactly how the Milky Way came to exist. But according to one popular model of galaxy formation, the building blocks of the Milky Way were dwarf galaxies that collided and merged shortly after the Big Bang.

This idea assumes that floating black holes, each containing 1,000 to 100,000 more mass than the sun, could be left over from those early cosmic times — fossil evidence for the growth and mergers of black holes in the infant universe.

kenobi-wan-obi:

No, Stephen Hawking Did Not Say Black Holes Don’t Exist

You’ve probably seen plenty of headlines this week proclaiming “Stephen Hawking Says Black Holes Don’t Exist,” and heard people who read those headlines chattering excitedly about this seemingly huge shift in astrophysics. But as PopMech wisely points out, that’s not an accurate summary of what Hawking actually said.

All of this stems from a short paper Hawking submitted on January 22nd, titled “Information Preservation and Weather Forecasting for Black Holes.” And yes, the phrase “there are no black holes” appears in that paper. But there isn’t a period at the end of it. In full, it states “there are no black holes—in the sense of regimes from which light can’t escape to infinity. There are, however, apparent horizons which persist for a period of time.”

As PopMech explains, Hawking is writing about the things that happen at the event horizon, the very edge of a black hole. The whole discussion is an excellent read, but the main takeaway is this: astrophysicists who understand this complex language consider the new paper a Hawking op-ed. As Don Marolf, a theoretical physicist who studies black holes at the University of California, Santa Barbara, told PopMech, “most people that I know that read the paper see this as an expression of his opinion on a current debate without necessarily adding new scientific ingredients.”

Of course, that’s not the last station for the misquote train. Andy Borowitz threw a 55-gallon barrel of kerosene on the confusion fire with his satirical column where he “quoted” Representative Michele Bachmann as saying, “if black holes don’t exist, then other things you scientists have been trying to foist on us probably don’t either, like climate change and evolution.” Far too many people took it seriously, which I guess is the mark of skillful satire.

(via afro-dominicano)

kenobi-wan-obi:

Milky Way’s Huge Black Hole to Gobble Gas Cloud Soon

A giant gas cloud is set to spiral into the supermassive black hole at the Milky Way’s core in the next few months, and scientists should get a great view of the dramatic celestial action.

NASA’s Swift satellite will have a front-row seat for the enormous gas cloud collision, and astronomers can barely contain their excitement.

"Everyone wants to see the event happening because it’s so rare," Nathalie Degenaar, of the University of Michigan, said in a statement.

Collision coming

In 2003, scientists discovered what seemed to be a cloud of gas, termed G2, which should collide in March or thereabouts with the supermassive black hole that lurks at the heart of the Milky Way. The interaction will reveal much about this black hole, which is known as Sagittarius A* (or Sag A* for short).

Although scientists have observed signs of such feeding in other galaxies, it’s rare to see these events so close to home.

With their enormous gravitational pull, the centers of black holes trap even light, making them difficult to see. But the edges of these odd objects light up up when they feed, emitting energy that can reveal details about black-hole dynamics.

Sag A* is dim even for a class of object known to be challenging to observe —almost 4,000 times fainter than astronomers expect it to be. Every 5 to 10 days, the hungry black hole gobbles down a bit of gas or dust that creates an X-ray flare that telescopes like Swift can capture.

For the last eight years, Degenaar and her team have used Swift to observe the galactic center for 17 minutes a day. On the whole, it’s been fairly quiet.

"Our supermassive black hole is laying low," Degenaar told reporters earlier this month. "It’s not displaying a lot of action at all."

That may well change when G2 crashes into Sag A, since the interaction could create an X-ray flare brighter than those generated by smaller objects. Degenaar’s team, still monitoring Sag A every day, will be in a perfect position to observe the changes, and other instruments will try to get a good look as well.

"Observatories all over the world, space- and ground-based, are ready for this," Degenaar said.

Continue to Full Article

(via afro-dominicano)

kenobi-wan-obi:

Astrophysicist Helps Crack A Black Hole Mystery: Energy Jets

With almost limitless gravitational power, black holes are supposed to gulp everything that comes near them, even weightless light photons.

So astronomers have long sought explanations for observations that black holes emit high-energy particles, often through visually impressive jets that unfurl from the black holes’ poles in thick, tornado-like coils. Now, in a paper published in this month’s edition of the Astrophysical Journal, a University of Florida researcher has bolstered and expanded a longtime theory about how and why these photons and electrons escape powerful gape of black holes, caused by the collapse of stars.

“My calculations may solve the mystery as to where the large number of high-energy observed electrons originate from,” said Reva Kay Williams, a UF courtesy postdoctoral associate. “My calculations also help explain some of our observations, such as why many (black hole) jets are observed to be uneven, or one-sided.”

Williams’ research is the first to prove the Penrose mechanism, a 35-year-old theory named for its author, Oxford University mathematics and physics professor Roger Penrose. It also provides a new, physical explanation for the odd appearance of many of the jets, which some astronomers believe was merely the result of an optical illusion.

Fernando de Felice, a physicist at the University of Padova in Italy, said Williams’ findings represent an important contribution to the field.

“Until recently, it was believed that the Penrose mechanism was not very efficient for generating energetic particles, but Dr. Williams’ detailed and perseverant work showed that this may not be true and, to the contrary, that it may be relevant to high-energy astrophysics,” he said.

Penrose’s theory says the rotational energy of a spinning black hole powers and lifts particles large distances away. Williams’ research, based in part on computer modeling, shows these particles appear to be created at the part of the hole where gravity is so powerful it bends light into a circle around the hole.

Her calculations also suggest the one-sided appearance of the jets is the result of the black holes’ gravitational dragging of space and time near their cores – not just, as some suggested, a consequence of the observer’s position relative to the jets. “The interest in Dr. Williams’ work is that it has enriched the possibilities of having energy output in active cosmic sources,” de Felice said.

(via afro-dominicano)

aamukherjee:

Redefining Black Holes

According to Stephen Hawking, we’ve got black holes all wrong

As far as we are concerned, a black hole is a structure in space with an event horizon past which no light or matter can escape and ends up being devoured. Hawking is proposing that instead of having a clear ‘event horizon’, black holes actually have an ‘apparent horizon' which constantly fluctuates due to quantum effects. 

One of the nifty consequences of this theorised model is that it resolves the firewall paradox which can be easily explained by considering an unfortunate astronaut falling into the event horizon of a black hole (RIP Mr. Astro).

Classical physics tells us that this poor soul would be stretched out and spaghettified (yes, this is a real word) until being crushed at the infinitely dense core. Quantum theory, however, suggests that the event horizon of a black hole would be a highly energetic reason and would act as a ‘firewall’ causing the astronaut to be burned to a crisp.

This is a big problem because it violates the equivalence principle which tells us that free falling is indistinguishable from floating in empty space (which obviously is not the case if find yourself being burned to a crisp). Another solution to the paradox suggests that information is simply lost in a black hole,  but this is also very controversial as it violates unitarity

Apparently, Hawking’s paper resolves this paradox. By replacing the event horizon with an apparent horizon, the theorised firewall can no longer exist as there is no uniform boundary to the black hole. However, the paper consists of just two pages with no calculations so it is very difficult for anyone to draw any definite conclusions. Some theorists have suggested that this theory could raise even more radical issues than the existence of firewalls. 

If Hawking’s past discoveries are anything to go by, this could turn into a very interesting debate. 

I’ve already seen a few posts concerning this paper, so here’s a brief explanation of why it’s such a big deal. 

kenobi-wan-obi:

Massive Black Hole Duo: Possible Sighting by NASA’s WISE

Astronomers have spotted what appear to be two supermassive black holes at the heart of a remote galaxy, circling each other like dance partners. The incredibly rare sighting was made with the help of NASA’s Wide-field Infrared Survey Explorer, or WISE.

Follow-up observations with the Australian Telescope Compact Array near Narrabri, Australia, and the Gemini South telescope in Chile, revealed unusual features in the galaxy, including a lumpy jet thought to be the result of one black hole causing the jet of the other to sway.

"We think the jet of one black hole is being wiggled by the other, like a dance with ribbons," said Chao-Wei Tsai of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who is lead author of a paper on the findings appearing in the Dec. 10 issue of Astrophysical Journal. "If so, it is likely the two black holes are fairly close and gravitationally entwined."

The findings could teach astronomers more about how supermassive black holes grow by merging with each other.

(via afro-dominicano)

kenobi-wan-obi:

Weird Black Hole’s Incredible Brightness Perplexes Scientists

A black-hole system in a neighboring galaxy is twice as bright as astronomers had thought possible, a new study reports.

The incredible luminosity of the system in question, which resides about 22 million light-years from Earth in the Pinwheel Galaxy, may force a rethink of the theories that explain how some black holes radiate energy, researchers said.

"As if black holes weren’t extreme enough, this is a really extreme one that is shining as brightly as it possibly can," study co-author Joel Bregman of the University of Michigan said in a statement. "It’s figured out a way to be more luminous than we thought possible."

kenobi-wan-obi:

Guts of Superfast Black Hole Jets Revealed

Astronomers have taken an unprecedented look at the superenergetic jets blasted out by black holes, and thus have answered a key question about the composition of these mysterious beams.

Scientists found evidence of nickel and iron in the jets emitted by a relatively small black hole, suggesting that “normal” matter plays a bigger role in these enigmatic structures than does exotic antimatter.

"We’ve known for a long time that jets contain electrons but haven’t got an overall negative charge, so there must be something positively charged in them, too," study co-author James Miller-Jones, from the Curtin University node of the International Centre for Radio Astronomy Research in Australia, said in a statement.

"Until now, it wasn’t clear whether the positive charge came from positrons, the antimatter ‘opposite’ of electrons, or positively charged atoms," Miller-Jones added. "Since our results found nickel and iron in these jets, we now know ordinary matter must be providing the positive charge."

Full Article

Anyone answered whether or not we live in a black hole already? Or if the shit is even possible? Did I ever see the movie contact?
scinerds scinerds Said:

afro-dominicano:

There have been some emerging theories from cosmology to astrophysics about whether or not we are in a black hole. While there’s no evidence yet, there doesn’t seem to be anything that rules out the possibility.

Most recently I read an article that theorized the possibility of hyper black holes in Did a hyper-black hole spawn the Universe? which posited that:

In a paper posted last week on the arXiv preprint server, Afshordi and his colleagues turn their attention to a proposal made in 2000 by a team including Gia Dvali, a physicist now at the Ludwig Maximilians University in Munich, Germany. In that model, our three-dimensional (3D) Universe is a membrane, or brane, that floats through a ‘bulk universe’ that has four spatial dimensions. Ashfordi’s team realized that if the bulk universe contained its own four-dimensional (4D) stars, some of them could collapse, forming 4D black holes in the same way that massive stars in our Universe do.

So while there isn’t any smoking gun on this theory that makes it a sure thing due to technical complications and limitations to how far we can see into the cosmos, it does kind of make sense considering how nature tends to repeat itself. It could very well be that this Universe is existing within a hyper black hole that’s existing in a 4D universe. If you wanna do some further reading check out: Every Black Hole May Hold a Hidden Universe

and "Advanced civilizations may live safely inside the supermassive black holes in the galactic nuclei without being visible from the outside.".

I saw Contact :) one of my favorites cause it’s one of the few scifi movies that does the concept of wormholes some justice.

A huge amount of radiation is generated by the million degree accretion disk of trapped gas whirling around the 4 billion solar mass black hole at our galaxy’s heart.

Makoto Inoue of the Institute of Astronomy and Astrophysics in Taipei, and Hiromitsu Yokoo of Chiba University are proposing that advanced civilizations might pool their resources to construct a ring of “power stations” at the galaxy’s core. They would orbit the central black hole just beyond its solar system-sized accretion disk.

Some fraction of the radiation seething from the disk would be reflected and focused onto the power plants. Each power plant would transmit collected energy as a collimated microwave beam from a 100-mile diameter antenna.

ikenbot:

Monster Black Holes Are Most Massive Ever Discovered

Scientists have discovered the largest black holes yet, and they’re far bigger than researchers expected based on the galaxies in which they were found. The discovery suggests we have much to learn about how monster black holes grow, scientists said.

All large galaxies are thought to harbor super-massive black holes at their hearts that contain millions to billions of times the mass of our sun. Until now, the largest black hole known was a mammoth dwelling in the giant elliptical galaxy Messier 87. This black hole has a mass 6.3 billion times that of the sun.

Now research suggests black holes in two nearby galaxies are even bigger. The scientists used the Gemini and Keck observatories in Hawaii and the McDonald Observatory in Texas to monitor the velocities of stars orbiting around the centers of a pair of galaxies. These velocities reveal the strength of the gravitational pull on those stars, which in turn is linked with the masses of the black holes lurking there.

The new findings suggest that one galaxy, known as NGC 3842, the brightest galaxy in the Leo cluster of galaxies nearly 320 million light years distant, has a central black hole 9.7 billion solar masses large. The other, named NGC 4889, the brightest galaxy in the Coma cluster more than 335 million light years away, has a black hole of comparable or larger mass. Both encompass regions or “event horizons” about five times the distance from the sun to Pluto.

“For comparison, these black holes are 2,500 times as massive as the black hole at the center of the Milky Way galaxy, whose event horizon is one-fifth the orbit of Mercury,” said study lead author Nicholas McConnell at the University of California, Berkeley. Astronomers had suspected that black holes more than 10 billion solar masses large exist, based on light from quasars, cosmic objects from the early universe that are no more than a light year or two across but are thousands of times brighter than our entire galaxy.

The light of quasars is thought to come from matter driven to incandescent brightness as it spirals at high speeds into supermassive black holes. This is the first time scientists have detected black holes approaching such theorized giants in size.

“These two new supermassive black holes are similar in mass to young quasars, and may be the missing link between quasars and the supermassive black holes we see today,” said study co-author Chung-Pei Ma, an astrophysicist at the University of California, Berkeley.

(via afro-dominicano)

thescienceofreality:

What Will First Photos of Black Holes Look Like?

A giant black hole is thought to lurk at the center of the Milky Way, but it has never been directly seen. Now astronomers have predicted what the first pictures of this black hole will look like when taken with technology soon to be available.

In particular, researchers have found that pictures of a black hole ― or, more precisely, the boundaries around them ― will take a crescent form, rather than the blobby shape that is often predicted.

By modeling what these pictures will look like, scientists say they are preparing to interpret the photos that will become available from telescopes currently under construction.

No one has been able to image a black hole,” said University of California, Berkeley student Ayman Bin Kamruddin, who presented a poster on the research last week in Long Beach, Calif., at the 221st meeting of the American Astronomical Society. “So far it’s been impossible because they’re too small in the sky. Right now we’re just getting some details about the structure, but we don’t have an image yet.”

Black holes themselves are invisible, of course, as not even light can escape their gravitational clutches. However, the boundary of a black hole — the point of no return called the event horizon — should be visible from the radiation emitted by matter falling into the black hole. “

Continue…