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Saturday, 30 July 2011

Is There Life in Black Holes?

The 'Gravitational Singularity'
Black holes are essentially regions of space whose gravitational pull is so strong that nothing -- not even light -- can escape. It's for that reason that the phenomena are called "black," since all light hitting them gets absorbed, leaving nothing for the viewer to see.
Black holes can be either rotating or non-rotating, according to current theory, but either way, a "gravitational singularity" lies at the center.
Surrounding each black hole, meanwhile, is an invisible boundary known as the "event horizon" that essentially marks the point of no return. Anything that reaches a black hole's event horizon is expected to get sucked toward its singularity, with no hope of escaping again.
Though much of our current conception of black holes comes from Einstein's theory of general relativity, there is a growing consensus that supermassive black holes exist at the center of most galaxies -- including our own Milky Way.

Death by 'Spaghettification'

As one might expect, the fate of objects that get sucked into black holes is not typically considered a happy one.
Possessing infinite density, the gravitational singularity is theorized to subject any matter passing through to a process known as "spaghettification." That evocative name alone should be enough to strike terror into even the bravest of hearts, and with good reason, for it's essentially just what it sounds like.
It's conceivable, though, that living matter might be able to exist within a black hole without being consigned to that harsh and eternal oblivion.

'Advanced Civilizations May Live Safely Inside'

So argues Dokuchaev, who suggests that there are stable, periodic planetary orbits inside black holes that neither begin nor end in the black hole's gravitational singularity. Rather, they orbit around and around somewhere between the event horizon and the singularity without ever approaching the singularity or its life-threatening "spaghettifier."
Such stable periodic orbits exist inside black holes for photons, and they may exist for planets as well, Dokuchaev writes.
"Advanced civilizations may live safely inside the supermassive black holes," he explains. "Stationary observers may exist just as anywhere on the planet Earth ... . The only thing needed is to put your vehicle or your planet to a stable periodic orbit inside the black hole."
In this intermediate ground between the black hole's inner and outer parts, then, there could be a safe ground for life to exist.

'Everything Is Possible'

However improbable Dokuchaev's theory might seem, the fact remains that even on our own planet, life has been discovered in places where we never thought it would be possible, such as in volcanic vents at the deepest parts of the oceans, Czysz noted.
"No one thought animals could have been alive in that hostile area; we assumed they needed oxygen to metabolize," he explained.
It turned out, however, that the organisms discovered could metabolize sulfur instead.
"No one would have postulated that until they saw it," Czysz added.
So could life exist in black holes in some form, even one not recognizable to us Earthlings?
"Everything is possible," Czysz conceded. "But is it probable? I doubt it."

Rare Fosil of Sea Reptile

Alaska scientists have discovered the fossil of a rare, prehistoric marine reptile that is likely the most complete remnant of the creature ever found in North America.
The nearly complete fossilized skeleton is of a thalattosaur, a long-tailed sea creature that plied warm, shallow waters in the early days of dinosaurs and became extinct at the end of the Triassic period some 200 million years ago.
The discovery of the fossil, found during an extreme low tide along the shore of the Tongass National Forest, was announced this week by the Museum of the North at the University of Alaska, Fairbanks.
Unlike most thalattosaur discoveries, which are fossilized remnants of individual bones and bone fragments, this specimen appeared to be a nearly full skeleton.
"In North America, this may be the most articulated specimen that we have right now," Baichtal said.
Scientists excavated the fossil in June and have been studying it to determine whether it represents a previously unknown species.
There are only about a dozen full thalattosaur specimens in the world, Baichtal said. "So the probability of this being something that wasn't seen before is probably pretty high," he said.
The find is likely the most northern discovery as well, Baichtal said. The fossil was found near the Tlingit Indian village of Kake in southeast Alaska.
Other thalattosaur discoveries have been made in British Columbia, Canada, as well as in Nevada and the Alps, though the best finds have been made in China, he said.

Black Hole For First TIme In X-Ray

The upsurge of prohibited gas toward a black hole has been obviously imaged for a initial time in X-rays. understand-ing how black holes grow and- how have a difference behaves in their heated gravity.

The black hole is during a core of a vast universe well well known as NGC 3115, which is located about 32 million light years from Earth. By imaging a prohibited gas during opposite distances from this supermassive black hole, astronomers have celebrated a vicious starting point where a suit of gas initial becomes dominated by a black hole’s sobriety and- falls inward. This stretch from a black hole is well well known as a “Bondi radius.”

“It’s sparkling to find such transparent justification for gas in a hold of a large black hole,” pronounced Ka-Wah Wong of a University of Alabama, who led a investigate which appears in a Jul 20th emanate of The Astrophysical Journal Letters. “Chand, ra’s solution appetite provides a singular event to understand- some-more about how black holes constraint element by study this circuitously object.”

As gas flows toward a black hole, it becomes squeezed, creation it hotter and- brighter, a signature right away reliable by a X-ray observations. The researchers found a climb in gas heat starts about 700 light years from a black hole, giving a place of a Bondi radius. This suggests a black hole in a core of NGC 3115 has a mass about dual billion times which of a sun, creation it a closest black hole of which distance to Earth.

The Chand-ra interpretation additionally uncover a gas tighten to a black hole in a core of a universe is denser than gas serve out, as predicted. Using a celebrated properties of a gas and- fanciful assumptions, a group afterwards estimated which any year gas weighing about 2 percent a mass of a object is being pulled opposite a Bondi radius toward a black hole.

Making sure assumptions about how most of a gas’s appetite changes in to radiation, astronomers would design to find a source which is some-more than a million times brighter in X-rays than what is seen in NGC 3115.
“A heading poser in astrophysics is how a area around large black holes can stay so dim, when there’s so most fuel accessible to light up,” pronounced co-author Jimmy Irwin, additionally of a UA in Tuscaloosa. “This black hole is a print kid for this problem.”

There have been during slightest dual probable explanations for this discrepancy. The initial is which most reduction element essentially falls onto a black hole than flows inside a Bondi radius. Another probability is which a acclimatisation of appetite in to deviation is most reduction fit than is assumed.

NASA’s Marshall Space Flight Center in Huntsville, Ala., manages a Chand-ra module for a agency’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chand-ra’s scholarship and- moody operations from Cambridge, Mass.


FLICKERING lights are annoying but they may have an upside. Visible light communication (VLC) uses rapid pulses of light to transmit information wirelessly.

Now it may be ready to compete with conventional Wi-Fi.
"At the heart of this technology is a new generation of high-brightness light-emitting diodes," says Harald Haas from the University of Edinburgh, UK. "Very simply, if the LED is on, you transmit a digital 1, if it's off you transmit a 0," Haas says. "They can be switched on and off very quickly, which gives nice opportunities for transmitting data."

It is possible to encode data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s. The LED intensity is modulated so rapidly that human eyes cannot notice, so the output appears constant.

More sophisticated techniques could dramatically increase VLC data rates. Teams at the University of Oxford and the University of Edinburgh are focusing on parallel data transmission using arrays of LEDs, where each LED transmits a different data stream. Other groups are using mixtures of red, green and blue LEDs to alter the light's frequency, with each frequency encoding a different data channel.

Li-Fi, as it has been dubbed, has already achieved blisteringly high speeds in the lab. Researchers at the Heinrich Hertz Institute in Berlin, Germany, have reached data rates of over 500 megabytes per second using a standard white-light LED. Haas has set up a spin-off firm to sell a consumer VLC transmitter that is due for launch next year. It is capable of transmitting data at 100 MB/s - faster than most UK broadband connections.

Once established, VLC could solve some major communication problems. In 2009, the US Federal Communications Commission warned of a looming spectrum crisis: because our mobile devices are so data-hungry we will soon run out of radio-frequency bandwidth. Li-Fi could free up bandwidth, especially as much of the infrastructure is already in place.

"There are around 14 billion light bulbs worldwide, they just need to be replaced with LED ones that transmit data," says Haas. "We reckon VLC is a factor of ten cheaper than Wi-Fi." Because it uses light rather than radio-frequency signals, VLC could be used safely in aircraft, integrated into medical devices and hospitals where Wi-Fi is banned, or even underwater, where Wi-Fi doesn't work at all.

"The time is right for VLC, I strongly believe that," says Haas, who presented his work at TED Global in Edinburgh last week.
But some sound a cautious note about VLC's prospects. It only works in direct line of sight, for example, although this also makes it harder to intercept than Wi-Fi. "There has been a lot of early hype, and there are some very good applications," says Mark Leeson from the University of Warwick, UK. "But I'm doubtful it's a panacea. This isn't technology without a point, but I don't think it sweeps all before it, either."

          With such speed we can download a movie in seconds, just knowledge, the fastest connection in the world still held by the 75-years-old Sibritt Löthberg from Karlstad Sweden with 40 Gbps.

Robots Understand Our World

Hema Koppula and Abhishek Anand at Cornell University in Ithaca, New York, hope to avoid this disappointing scenario by teaching robots to understand the context of their surroundings so that they can pick out individual objects in a room. "We have developed an algorithm that learns to identify the objects in home and office scenes," explains Koppula.

Key to the system is Microsoft's Kinect sensor, which perceives real-world 3D scenes by combining two visible-light cameras with depth information from an infrared sensor. Koppula and Anand's algorithm learns to recognise particular objects by studying images labelled with descriptive tags such as "windows", "books" and "tables".

The researchers used 27 labels in total, 10 each for office and home scenes and seven that applied to both.
Previous approaches to the problem have used expensive depth sensors that couldn't provide colour information, but the cheap Kinect can do both, allowing the algorithm to consider both shape and colour when evaluating an object. The system also takes relative locations into account – for example, computer monitors are normally found on top of a table, rather than underneath.

It turns out office locations are easier to classify than home scenes, with Koppula and Anand's algorithm achieving 84 per cent recognition success in the former versus 74 per cent in the latter. Koppula puts this down to the lack of variety in office environments compared with our more personalised homes. This way “they” will be able to help even replace our job someday,

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