The "Great Filter" is a hypothetical barrier to explain why civilisations are so unlikely to progress to the point of inter-stellar colonisation that we have not encountered any in 40 years of looking. Maybe humanity has already negotiated the filter - as some massive evolutionary improbability - or perhaps it lies in our future as an almost-certain threat to our existence? We should hold our breath as we look for evidence of life on Mars.
posted by rongorongo on May 12, 2008 - 85 comments

Fears that malevolent aliens will tune into this week's broadcast of The Beatles' song "Across the Universe" have been voiced by scientists.
posted by monospace on Feb 7, 2008 - 68 comments

September 30th, 2002, scientists intercepted a 10 minute radio burst from the galactic center, 26,000 Light Years away. 77 minutes passed, and it repeated. And again. The signal repeated 5 times that evening.

Some think those signals are weird mysterious. Others think they are interesting mysterious.
posted by Lord_Pall on Oct 25, 2006 - 63 comments

The number of communicating alien civilizations = R^* x f_p x n_e x f_l x f_i x f_c x L. The formula is the Drake Equation, and modern estimates range from several thousand to none but us. You can solve it yourself. What is your estimate of the number of alien civilizations out there?
posted by blahblahblah on Aug 27, 2006 - 88 comments

'Alien' art Artist Jonathon Keats has made abstract paintings from SHGb02+14a, a radio signal discovered by SETI@home in 2003, then dubbed their best candidate yet for an attempt at contact by intelligent aliens. Keats is also returning the favour, broadcasting his work into space from the Judah L. Magnes Museum using CB radio.
posted by jack_mo on Aug 3, 2006 - 19 comments

Aliens and Children. This website features a series of drawings made by children who were abducted by aliens for the purpose of creating a new race of alien/human hybrids. They successfully resisted the aliens by using a thought screen helmet which blocks the telepathic control aliens have over humans.
posted by Robot Johnny on Feb 12, 2006 - 35 comments

Call the aliens using first intentional intergalactic communication system. Just $3.99 a minute, though prospective callers should know that they aren't really breaking new ground. Do you need inspiration about what historic message to send? The first commercial telegraph message was the poetic "What hath God wrought?" The first telephone call was the famous "Come here Watson, I want to see you." The first email, rather boringly, announced the availability of email. Stuck on the first word? Follow the path of Edison, who coined the word "hello" as a telephone greeting over Alexander Graham Bell's "Ahoy Ahoy." (Audio version) Just hope that you don't receive a collect call in return.
posted by blahblahblah on Oct 18, 2005 - 14 comments

Have aliens answered our message? In 1974, as part of the SETI project, an encoded message was sent from the Arecibo radio telescope in Puerto Rico. On the 20th August, near the Chilbolton radio telescope in Hampshire, England, an amazing crop circle was discovered that appeared to answer the message....
posted by salmacis on Nov 14, 2001 - 25 comments

Science on the cheap! Now this is cool. (more inside)
posted by Steven Den Beste on Aug 3, 2000 - 3 comments