Archive for June 2007

Blackhole Info-loss paradox: Cracked?

Physicist may have finally cracked the black hole information loss paradox that has befuddled physicists for the past 40 years, according to an article accepted for publication by Physical Review D, which concludes that that an outside observer can never lose objects down a black hole.

The question that the physicists set out to solve is: “what happens once something collapses into a black hole?”

If all information about the collapsing matter is lost, it defies the laws of quantum physics. Yet, in current thinking, once the matter goes over the event horizon and forms a black hole, all information about it is lost.

“If you define the black hole as some place where you can lose objects, then there is no such thing because the black hole evaporates before anything is seen to fall in,” said Vachaspati.

According to the researchers, if black holes exist, information formed in the initial state would disappear in the black hole through a burst of thermal radiation that carries no information about the initial state.

Using the functional Schrodinger formalism, the researchers suggest that information about the energy from radiation is long evaporated before an event horizon forms.

“An outside observer will never lose an object down a black hole,” said Stojkovic. “If you are sitting outside and throwing something into the black hole, it will never pass over but will stay outside the event horizon even if one considers the effects of quantum mechanics. In fact, since in quantum mechanics the observer plays an important role in measurement, the question of formation of an event horizon is much more subtle to consider.”

For more see: PressEsc.com

Progress made toward lunar liquid mirror telescope

Scientists have taken a giant leap toward making possible the dream of building a powerful telescope on the moon that could withstand even the harshest of lunar conditions.

Writing in Thursday’s edition of the journal Nature, they said they coated a special type of liquid surface with a layer of silver to make a highly reflective mirror like one that could be used in any future, moon-based telescope.

“It’s the breakthrough that we need,” lead researcher Ermanno Borra of Universite Laval in Quebec, Canada, said in a telephone interview. “If you want to have a liquid mirror telescope on the moon, you need the right liquid. If you don’t have the right liquid, forget it. It’s as simple as that.”

Borra envisions a telescope with a liquid mirror measuring 66 feet to 328 feet wide.

Such a telescope, which has drawn NASA’s interest, could provide astronomers on Earth unprecedented views into distant reaches of the universe, studying objects far more faint even than NASA’s planned James Webb Space Telescope, due for a 2013 launch.

Astronomers hope such an instrument could allow them to study the early phases of the universe after the Big Bang.

Progress made toward lunar liquid mirror telescope | Science | Reuters

Cyber Attack Hits Pentagon

(WASHINGTON)—The Defense Department took as many as 1,500 computers off line because of a cyber attack, Pentagon officials said Thursday.

Few details were released about the attack, which happened Wednesday, but Defense Secretary Robert Gates said the computer systems would be working again soon.

Gates said the Pentagon sees hundreds of attacks a day, and this one had no adverse impact on department operations. Employees whose computers were affected could still use their handheld BlackBerrys.

During a press briefing Gates said: “We obviously have redundant systems in place. … There will be some administrative disruptions and personal inconveniences.”

Cyber Attack Hits Pentagon | TIME

Eta Carinae, when will it blow?

Eta Carinae is a mysterious, extremely bright and unstable star located a mere stone’s throw – astronomically speaking – from Earth at a distance of only about 7,500 light years. The star is thought to be consuming its nuclear fuel at an incredible rate, while quickly drawing closer to its ultimate explosive demise. When Eta Carinae does explode, it will be a spectacular fireworks display seen from Earth, perhaps rivaling the moon in brilliance. Its fate has been foreshadowed by the recent discovery of SN2006gy, a supernova in a nearby galaxy that was the brightest stellar explosion ever seen. The erratic behavior of the star that later exploded as SN2006gy suggests that Eta Carinae may explode at any time.

Eta Carinae, a star between 100 and 150 times more massive than the Sun, is near a point of unstable equilibrium where the star’s gravity is almost balanced by the outward pressure of the intense radiation generated in the nuclear furnace. This means that slight perturbations of the star might cause enormous ejections of matter from its surface. In the 1840s, Eta Carinae had a massive eruption by ejecting more than 10 times the mass of the sun, to briefly become the second brightest star in the sky. This explosion would have torn most other stars to pieces but somehow Eta Carinae survived.

Chandra X-Ray Observatory

Mars rover finds water puddles?

A new analysis of pictures taken by the exploration rover Opportunity reveals what appear to be small ponds of liquid water on the surface of Mars.

The report identifies specific spots that appear to have contained liquid water two years ago, when Opportunity was exploring a crater called Endurance. It is a highly controversial claim, as many scientists believe that liquid water cannot exist on the surface of Mars today because of the planet’s thin atmosphere.

If confirmed, the existence of such ponds would significantly boost the odds that living organisms could survive on or near the surface of Mars, says physicist Ron Levin, the report’s lead author, who works in advanced image processing at the aerospace company Lockheed Martin in Arizona.

Along with fellow Lockheed engineer Daniel Lyddy, Levin used images from the Jet Propulsion Laboratory’s website. The resulting stereoscopic reconstructions, made from paired images from the Opportunity rover’s twin cameras, show bluish features that look perfectly flat. The surfaces are so smooth that the computer could not find any surface details within those areas to match up between the two images.

The imaging shows that the areas occupy the lowest parts of the terrain. They also appear transparent: some features, which Levin says may be submerged rocks or pebbles, can be seen below the plane of the smooth surface.

Mars rover finds “puddles” on the planet’s surface – space – 08 June 2007 – New Scientist Space