Trying to catch alien whispers from outer space

June 28th, 2008 - 3:54 pm ICT by IANS  

Washington, June 28 (IANS) If aliens were hovering high above the earth, the first sounds they would be chirps and whistles - the sounds that accompany an aurora. Now European Space Agency’s (ESA) Cluster mission is enabling scientists understand this emission and search for alien worlds by listening for their sounds, according to a release.

Scientists call this radio emission Auroral Kilometric Radiation (AKR), that is generated by the same shaft of solar particles that causes an aurora to light up the sky beneath.

For decades, astronomers had presumed that these radio waves travelled into space in an ever-widening cone, rather like light emitted from a torch. Thanks to Cluster, astronomers now know this is not true.

By analysing 12,000 separate bursts of AKR, astronomers have determined it is beamed in a narrow plane, like masking the torch leaving only a tiny slit in its middle for the light to escape.

“We can now determine exactly where the emission is coming from,” says Robert Mutel, University of Iowa, who conducted the three-year study with colleagues.

For each of the AKR bursts they analysed, the astronomers pinpointed their origin to areas in earth’s magnetic field a few tens of kilometres in size. These were located a few thousand kilometres above where the light of the aurora is formed.

“This result was only possible because of the Cluster mission’s four spacecraft,” said Mutel. Consisting of four nearly identical spacecraft flying in formation, Cluster allowed the scientists to precisely time when the AKR washed over each of the satellites.

Using this information, the scientists triangulated the points of origin, in a similar way to the way GPS navigation works.

“ESA’s Cluster mission is showing scientists how to understand this emission and, in the future, search for alien worlds by listening for their chirps and whistles.”

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