Is it true that there could be intelligent life out there?
Despite the huge number of sightings, abductions and government sponsored cover-ups that have allegedly taken place over the years, there is no proof that alien life exists. But this doesn’t stop researchers looking.
Searching for aliens
The Search for Extra-Terrestrial Intelligence (SETI) is based at the University of California in Berkley and has several radio telescopes that are dedicated to listening out for signals from alternative life forms. The researchers need to be dedicated since despite constant searching after picking up a promising signal in 1977, they haven’t heard anything else.
But SETI isn’t just waiting for intelligent aliens to contact us. In 1974, they beamed their own signal out into space from the Arecibo telescope in Puerto Rico. The signal is a binary radio message which, when displayed as a rectangle of squares and spaces, makes up a picture of a human, our position in the solar system and even the structure of our DNA.
The signal was aimed towards the imaginatively titled M13 area of the universe, which is a huge cluster of stars 25,000 light years away. The thinking was that such a large number of stars had a high chance of harbouring a planet with intelligent life. However, we still have another 24,966 years to wait before the signal reaches the area.
Intelligent life in the Milky Way
But could there be intelligent life sharing the Milky Way with us? Consider the number of stars like our Sun in the Milky Way, then take the fraction of stars which have planets orbiting them, then take the fraction of planets with a suitable environment for life to evolve, then take the fraction of those planets where life has evolved, then take the fraction where life on those planets is intelligent. Finally, take the fraction of intelligent life that is capable of communication, and then take the mean lifetime of that life form. There is a fair bit of guesswork involved in predicting some of these variables, but the outcome is thought to be an estimated 72 civilisations in the Milky Way which are able to communicate. This calculation is called the Drake Equation first written down by Frank Drake who is now the Director of SETI.
But even with so many possible intelligent life forms capable of communication out there, the distances involved mean that it’s likely they would be at least 200 light years away. This means that a conversation with even the chattiest of aliens would involve waiting 400 years for a reply to the simplest question. It would be the ultimate long distance relationship!
Find related websites for SETI with physics.org