Many scientists refuse to believe that humans are alone, given the 200 billion stars in our galaxy.
Scientists like Seth Shostack not only believe that other intelligent life forms exist on other planets, but that their civilizations have advanced enough through evolution that they would be able to transmit radio messages.
“To think ‘hey, look man, this is the only place where there’s anything interesting happening’; I mean you’ve gotta be really audacious to take that point of view,” Shostack said.
However, for a discouraging period of 50 years, Seti (Search for Extra-Terrestrial Intelligence) has not heard anything coming from another galaxy.
Since the discovery of a huge planet orbiting the star Pegasi 51, 260 other exoplanets have been discovered, but none of them seemed to be habitable.
Then, in 2007 Professor Stephan Udry and his Swiss team of astronomers identified the planet Gliese 581c. It is the smallest planet orbiting a main sequence star yet found in our galaxy. Its size and distance from its star to indicate that it could be habitable.
The mystery remains, as no one has any proof that life exists on Gliese 581c, however, scientist such as Dr Lynn Rothschild are able to calculate some of the planet’s characteristics.
They estimate that the planet’s landscape will be much different from Earth’s as it will not have mountains, just low plains and hills. Also, the gravity on the planet would be twice as strong as that of the Earth’s.
The star of the system would appear much larger in the sky than the sun does on Earth. It would also cast a reddish light.
However, the theory of life on Gliese 581c has its critics. Professor Geoff Marcy’s team has found more than 100 planets. After studying the planet he is convinced that it is not habitable.
Both sides may have an answer in the near future.
In 2009, NASA plans to launch Kepler, a space telescope intended to seek out new worlds. It is designed to be sensitive enough to detect Earth-like planets from day one. It will scan an incredible 100,000 stars day and night for four years, according to BBC News.
Even NASA estimates that at least 50 Earth-like planets exist within the Milky Way.
Meanwhile, 300 miles north of San Francisco, the giant Allen Telescope Array is being built. Consisting of computer-controlled off-the-shelf radio antennas, scientists intend to eventually reach 300 dishes, making it the most powerful attempt yet to listen for an alien message.
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