Earth’s clearest skies visible from Antarctic plateau

A research team has found that the Antarctic plateau offers world-beating atmospheric conditions to view possibly the clearest skies on Earth.

According to a report in New Scientist, Michael Ashley of the University of New South Wales in Sydney, Australia, and his colleagues wanted to find the best sites for astronomy on the Antarctic plateau.

Combining observations from satellites and ground stations with climate models, they evaluated different factors that affect telescope vision, such as the amount of water vapour, wind speeds and atmospheric turbulence.

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Scientists learn what makes Northern Lights flare

The multicolored aurora borealis and aurora australis -- the Northern Lights and Southern Lights -- represent some of Earth's most dazzling natural displays.

Now scientists using data from five NASA satellites have learned what causes frequent auroral flare-ups that make this green, red and purple light show that shimmers above Earth's northernmost and southernmost regions even more spectacular.

Writing in the journal Science, the scientists said on Thursday that explosions of magnetic energy occurring a third of the way between Earth and the moon drive the sudden brightening of the Northern Lights and Southern Lights.

There had been debate among scientists dating back decades about what triggers these auroral flare-ups.

The findings from the THEMIS satellites and a network of 20 ground observatories in Canada and Alaska confirmed that it is due to a process called "magnetic reconnection." THEMIS stands for Time History of Events and Macroscale Interactions during Substorms mission.

Auroral displays are associated with the solar wind -- electrically charged particles continuously spewing outward from the sun. Earth's magnetic field lines reach far out into space as they store energy from the solar wind.

The researchers said that as two magnetic field lines come close together due to the storage of energy from the sun, a critical limit is reached and the lines reconnect, causing magnetic energy to be turned into kinetic energy and heat. The release of this energy sparks the auroral flare-ups.

"We showed that the process begins far from Earth first and propagates Earthward later," said Vassilis Angelopoulos of the University of California at Los Angeles, who led the research.

The moon is located about 240,000 miles from Earth, and this process is occurring roughly 80,000 miles from Earth.

The same mechanism causing the auroral brightening also can cause problems for satellites, power grids and communications systems on Earth and could endanger astronauts in space, the researchers said.

Earth was a slushball

An extraordinary episode of global cooling hundreds of millions of years ago that some experts say caused Earth to completely freeze over has been miscalculated, a new study says. Instead of "Snowball Earth," the planet really became "Slushball Earth," its authors suggest. The great chill - the longest and deepest ice age in Earth's known history happened during the late Neoproterozoic era, 850 to 542 million years ago. The evidence for the Snowball thesis comes from deep sediments in the ocean. Scientists look through these layers to measure levels of the isotope carbon 13 (C13), deposited in plants through photosynthesis, as a telltale of Earth's climate.

Above and below the Cryogenian layer is an abundance of C13. But the Cryogenian layer has negligible levels of this isotope. The explanation is that Earth froze over completely and glaciers crept down into the tropics, possibly even reaching the equator. The brilliant white shell reflected back the Sun's rays, and thus its heat, so well that the Snowball persisted for nearly 200 million years. Eventually the greenhouse gas carbon dioxide (CO2), welling up from volcanoes, escaped into the air and thankfully set the planet onto a warming trend, and so the icy blanket was melted.

Image and Article source: Deccan Chronicle

Can Earth survive Sun's explosion?

In just two months, two planets, as old as the Universe itself have been discovered, suggesting life could have begun long before the earth was formed.
Peg V392b is the latest and oldest planet known to man.
Thirteen billion years old, it circles a dying star at the same distance we circle our Sun.
By surviving its stars' explosive death throes, the planet suggests Earth too might survive when the sun explodes five billion years from now.
Interestingly, just two months ago, another planet enjoyed the "Oldest in the Universe" tag. 12.7 billion years old and 7,200 light-years away, this one once orbited a star as pleasant as our Sun is now.
Its discovery had astronomers wondering if life didn't begin long before the Earth was formed.

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