NASA( National Aeronautics and Space Administration) finds cold stars with WISE telescope

Astronomers have discovered 6 Y dwarfs approximately 40 light-years away from the sun.

The dark orbs, which are categorized as the coldest class of star-like bodies, were tracked down by NASA's WISE infrared telescope.

"WISE scanned the entire sky for these and other objects, and was able to spot their feeble light with its highly sensitive infrared vision," explained Jon Morse, Astrophysics Division director at NASA Headquarters in Washington.

"They are 5,000 times brighter at the longer infrared wavelengths WISE observed from space than those observable from the ground."

According to Morse, the Y's are the coldest members of the brown dwarf family, which are sometimes referred to as "failed" stars.

They are simply too low in mass to fuse atoms at their cores - and thus don't burn with the fires that keep stars like our sun shining steadily for billions of years.

Instead, these objects cool and fade with time, until what little light they do emit is "visible" only at infrared wavelengths.

NASA astronomers are keen to study brown dwarfs, as they can help scientists better understand how stars form, while providing additional data about the atmospheres of planets beyond our solar system.

For example, the atmospheres of brown dwarfs are similar to those of gas-giant planets like Jupiter, but are easier to observe because they are alone in space, well away from the blinding light of a parent star

.



So far, WISE has detected 100 new brown dwarfs, with more discoveries expected as scientists continue to examine an enormous quantity of data from the telescope.

Of the 100 brown dwarfs, six are classified as cool Y's. One of the Y dwarfs, known as WISE 1828+2650, is the record holder for the coldest brown dwarf, with an estimated atmospheric temperature cooler than room temperature, or less than about 80 degrees Fahrenheit (25 degrees Celsius).

"The brown dwarfs we were turning up before this discovery were more like the temperature of your oven," said Davy Kirkpatrick, a WISE science team member at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, Calif.

"With the discovery of Y dwarfs, we've moved out of the kitchen and into the cooler parts of the house."

Read More

Black hole was seen swallowing a star!!!

Astronomers have spotted a super massive black hole in the act of shredding and consuming a star 3.9 billion light years away. NASA's Swift satellite first picked up intense and unusual high-energy X-ray and gamma-ray flares from the constellation Draco in March - and soon realized that the source, Swift J1644+57, was a black hole flaring up as it swallowed up a star. "Incredibly, this source is still producing X-rays and may remain bright enough for Swift to observe into next year," says David Burrows, professor of astronomy at Penn State University and lead scientist for the mission's X-Ray Telescope instrument. "It behaves unlike anything we've seen before."

The black hole in the galaxy hosting Swift J1644+57 appears to be about twice the mass of the black hole at the center of our own Milky Way galaxy, at about eight million solar masses.

As a star falls toward a black hole, the intense tides rip it into pieces, creating a disk of gas that swirls around the black hole and becomes rapidly heated to temperatures of millions of degrees

Star swallowed

.

The gas towards the center of the disk spirals towards the black hole, where rapid motion and magnetism create paired 'funnels' through which some particles may escape. Jets form, squirting out matter at more than 90 percent of the speed of light.

"The radio emission occurs when the outgoing jet slams into the interstellar environment," says Ashley Zauderer, a post-doctoral fellow at the Harvard-Smithsonian Center for Astrophysics. "By contrast, the X-rays arise much closer to the black hole, likely near the base of the jet."

And, in the case of Swift J1644+57, one of these jets happens to point straight at Earth, accounting for the brightness of the flares

Black Hole

 .

When they were first detected, the flares were initially assumed to signal a gamma-ray burst - one of the near-daily short blasts of high-energy radiation often associated with the death of a massive star and the birth of a black hole in the distant universe.

But as the emission continued to brighten and flare, astronomers realized that the most likely explanation was the tidal disruption of a sun-like star showing up as a beamed emission.

"Our observations show that the radio-emitting region is still expanding at more than half the speed of light," says Edo Berger, an associate professor of astrophysics at Harvard. "By tracking this expansion backward in time, we can confirm that the outflow formed at the same time as the Swift X-ray source."

Black Hole Swallowing Star

Read More

Steve Jobs resigns, Tim Cook is new Apple CEO

Steve Jobs has resigned as Apple's Chief Executive Officer. Tim Cook, previously Cupertino's Chief Operating Officer, is Apple's new CEO. 



"I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple's CEO, I would be the first to let you know. Unfortunately, that day has come," Steve Jobs wrote in an open letter

Steve Jobs

.

"I hereby resign as CEO of Apple. I would like to serve, if the Board sees fit, as Chairman of the Board, director and Apple employee. As far as my successor goes, I strongly recommend that we execute our succession plan and name Tim Cook as CEO of Apple."

As expected, Jobs was elected Chairman of the Board immediately after tendering his resignation.

Art Levinson, who spoke on behalf of the Board, emphasized that he had "complete confidence" in Tim Cook - who was the "right person" to be Apple's next CEO

Tim Cook

.

"Tim's 13 years of service to Apple have been marked by outstanding performance, and he has demonstrated remarkable talent and sound judgment in everything he does," said Levinson.
 
As CEO, Cook was previously responsible for all of the company's worldwide sales and operations, including end-to-end management of Apple's supply chain, sales activities, and service and support in all markets and countries.

He also headed Apple's Macintosh division and played a key role in the continued development of strategic reseller and supplier relationships.

Steve Jobs & Tim Cook

Read More

Oldest fossils on Earth discovered!!!

The Earth's oldest fossils that show convincing evidence of cells and bacteria living in an oxygen-free world over 3.4 billion years ago have been discovered.

The discovery has been made by a team led by Dr David Wacey of the University of Western Australia and including Professor Martin Brasier of Oxford University, according to findings reported in the journal Nature Geoscience.

"At last we have good solid evidence for life over 3.4 billion years ago. It confirms there were bacteria at this time, living without oxygen," says Professor Brasier of the Department of Earth Sciences at Oxford

The Earth was still a hot, violent place at this time, with volcanic activity dominating the early Earth.

The sky was cloudy and grey, keeping the heat in despite the sun being weaker than today, a university release said.

The water temperature of the oceans was much higher at 40-50 degrees and circulating currents were very strong.

Any land masses were small, or about the size of Caribbean islands, and the tidal range was huge.

Significantly, there was very little oxygen present as there were no plants or algae yet to photosynthesise and produce oxygen.

The new evidence points to early life being sulphur-based, living off and metabolising compounds containing sulphur rather than oxygen for energy and growth.

"Such bacteria are still common today. Sulphur bacteria are found in smelly ditches, soil, hot springs, hydrothermal vents anywhere where there's little free oxygen and they can live off organic matter," explains Professor Brasier.

The microfossils were found in a remote part of Western Australia called Strelley Pool.

They are very well preserved between the quartz sand grains of the oldest beach or shoreline known on Earth, in some of the oldest sedimentary rocks that can be found anywhere.

Professor Brasier said: "We can be very sure about the age as the rocks were formed between two volcanic successions that narrow the possible age down to a few tens of millions of years. That's very accurate indeed when the rocks are 3.4 billion years old".

The fossils are very clearly preserved showing precise cell-like structures all of a similar size.

They look like well known but much newer microfossils from 2 billion years ago, and are not odd or strained in shape.

The fossils suggest biological-like behaviour.

The cells are clustered in groups, are only present in appropriate habitats and are found attached to sand grains.

The fossils also show biological metabolisms.

The chemical make-up of the tiny fossilised structures is right, and crystals of pyrite (fool's gold) associated with the microfossils are very likely to be by-products of the sulphur metabolism of these ancient cells and bacteria.

Early fossils of life on Earth have been a controversial area.

In the past decade, the barriers that need to be overcome before claiming such evidence have been raised significantly, aided by new techniques for mapping the chemistry of rocks at fine scales.

The work has implications for looking for life on other planets, giving an indication of what evidence for such life might look like.

Should there be life elsewhere in our solar system on Mars or on the moons of Titan or Europa it is likely to be similar sorts of bacteria and cells living in similar environments.

So any fossils in rocks from these planets and moons ought to look like these Australian microfossils and pass the same evidence tests

Oldest fossil
The chemical make-up of the tiny fossilised structures is right, and crystals of pyrite (fool's gold) associated with the microfossils are very likely to be by-products of the sulphur metabolism of these ancient cells and bacteria.

.

Professor Brasier said: "Could these sorts of things exist on Mars? It's just about conceivable. But it would need these approaches mapping the chemistry of any microfossils in fine detail and convincing three-dimensional images to support any evidence for life on Mars".

Early fossils of life on Earth has been a controversial area.

In the past decade, the barriers that need to be overcome before claiming such evidence have been raised significantly, aided by new techniques for mapping the chemistry of rocks at fine scales.

The work has implications for looking for life on other planets, giving an indication of what evidence for such life might look like.

Should there be life elsewhere in our solar system on Mars or on the moons of Titan or Europa it is likely to be similar sorts of bacteria and cells living in similar environments.

So any fossils in rocks from these planets and moons ought to look like these Australian microfossils and pass the same evidence tests.

Professor Brasier said: "Could these sorts of things exist on Mars? It's just about conceivable. But it would need these approaches mapping the chemistry of any microfossils in fine detail and convincing three-dimensional images to support any evidence for life on Mars"

Read More

NASA says water may be flowing on Mars!!!

Recent images captured by NASA's Mars Reconnaissance Orbiter seem to indicate the presence of flowing water during the warmest months on the red planet.

Indeed, the images show dark, finger-like features that appear and extend down some Martian slopes during late spring through summer, fade in winter and return during the next spring.

Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars' southern hemisphere.

"The best explanation for these observations so far is the flow of briny water," said Alfred McEwen of the University of Arizona, Tucson.

However, certain aspects of the observations still puzzle researchers, but flows of liquid brine fit the features' characteristics better than alternate hypotheses. 

To be sure, saltiness lowers the freezing temperature of water. Sites with active flows get warm enough - even in the shallow subsurface - to sustain liquid water that is about as salty as Earth's oceans, while pure water would freeze at the observed temperatures.

"These dark lineations are different from other types of features on Martian slopes," confirmed Mars Reconnaissance Orbiter Project Scientist Richard Zurek of NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"Repeated observations show they extend ever farther downhill with time during the warm season."

The features imaged are only about 0.5 to 5 yards or meters wide, with lengths up to hundreds of yards. The width is much narrower than previously reported gullies on Martian slopes. Nevertheless, some of those locations display more than 1,000 individual flows. 

In addition, while gullies are abundant on cold, pole-facing slopes, these dark flows are on warmer, equator-facing slopes.

As noted above, the images show flows lengthen and darken on rocky equator-facing slopes from late spring to early fall. 

The seasonality, latitude distribution and brightness changes, suggest a volatile material is involved, but there is no direct detection of one. The settings are too warm for carbon-dioxide frost and, at some sites, too cold for pure water. This indicates the action of brines, which have lower freezing points.

Interestingly enough, salt deposits over much of Mars indicate brines were abundant in Mars' past. These recent observations suggest brines still may form near the surface today in limited times and places.

When researchers checked flow-marked slopes with the orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), no sign of water appeared. Still, the features may quickly dry on the surface or could be shallow subsurface flows.

"The flows are not dark because of being wet," McEwen explained. "They are dark for some other reason."

A flow initiated by briny water could rearrange grains or change surface roughness in a way that darkens the appearance. How the features brighten again when temperatures drop is harder to explain.

"It's a mystery now, but I think it's a solvable mystery with further observations and laboratory experiments," he added.

It should be noted that these results are the closest scientists have come to finding evidence of liquid water on the planet's surface today.
 Of course, frozen water has been detected near the surface in many middle to high-latitude region, while fresh-looking gullies suggest slope movements in geologically recent times, perhaps aided by water. 



Purported droplets of brine also appeared on struts of the Phoenix Mars Lander. If further study of the recurring dark flows supports evidence of brines, these could be the first known Martian locations with liquid water.

Read More