NASA Satellites Reveal Sudden Greenland Ice Sheet Melt

Greenland ice, it seems, can vanish in a flash, with new satellite images showing that over just a few days this month nearly all of the veneer of surface ice atop the island’s massive ice sheet had thawed. That’s a record for the largest area of surface melt on Greenland in more than 30 years of satellite observations, according to NASA and university scientists.

The images, snapped by three satellites, showed that about 40 percent of the ice sheet had thawed at or near the surface on July 8; just days later, on July 12, images showed a dramatic increase in melting with thawing across 97 percent of the ice sheet surface.

“This was so extraordinary that at first I questioned the result: was this real or was it due to a data error?” said Son Nghiem of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., referring to the July 12 images taken by the Indian Space Research Organisation’s (ISRO) Oceansat-2 satellite.


Nghiem had reason to be baffled, as this record ice-melt is well above average: About half of Greenland’s surface ice tends to melt every summer, with the meltwater at higher elevations quickly refreezing in place and the coastal meltwater either pooling on top of the ice or draining into the sea.  Instruments on two other satellites proved out Nghiem’s findings — the Moderate-resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites.

As for what caused the disappearing ice, University of Georgia, Athens climatologist Thomas Mote suggests it could be a ridge or dome of warm air hovering over Greenland that coincided with the extreme melt. If melted completely, the Greenland ice sheet could contribute 23 feet (7 meters) to global sea-level rise, according to a 2007 report by the Intergovernmental Panel on Climate Change (IPCC), the international body charged with assessing climate change.

Scientists say that man-made global warming, a result of greenhouse gas emissions, is contributing to Greenland ice melt. In fact, past research has suggested that the Greenland ice sheet will vanish in 2,000 years under business-as-usual carbon emissions.

Should we be worried about this sudden Greenland ice sheet melt? How should this problem be addressed?

Source: Yahoo News

Image: The Guardian

NASA’s Spitzer Detects Light From Alien Super-Earth For First Time

Light from an alien “super-Earth” twice the size of our own Earth has been detected by a NASA space telescope for the first time in what astronomers are calling a historic achievement.

NASA’s infrared Spitzer Space Telescope spotted light from the alien planet 55 Cancri e, which orbits a star 41 light-years from Earth. A year on the extrasolar planet lasts just 18 hours. The planet 55 Cancri e was first discovered in 2004 and is not a habitable world. Instead, it is known as a super-Earth because of its size: The world is about twice the width of Earth and has about eight times the mass of Earth. But until now, scientists have never managed to detect the infrared light from the super-Earth world.


Past observations of the planet 0by the Spitzer Space Telescope have suggested that one-fifth of 55 Cancri e is made up of lighter elements, including water. But the extreme temperatures and pressures on 55 Cancri e would create what scientists call a “supercritical fluid” state. Supercritical fluids can be imagined as a gas in a liquid state, which can occur under extreme pressures and temperatures. On Earth, water can become a supercritical fluid inside some steam engines.

Spitzer’s new look at 55 Cancri e is consistent with supercritical-fluid waterworld theory. The planet is likely a rocky world covered with water in a supercritical fluid state and topped off with a steam blanket, researchers said. The research is detailed in the Astrophysical Journal.

“When we conceived of Spitzer more than 40 years ago, exoplanets hadn’t even been discovered,” said Michael Werner, Spitzer project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Because Spitzer was built very well, it’s been able to adapt to this new field and make historic advances such as this.”

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Source: Yahoo News

Image: WN