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Space Disco : Discovery Space

The Search For Extraterrestrial Polluters

19 Oct 2009, 23:16 UTC
The Search For Extraterrestrial Polluters
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So how do you go about spotting an alien civilization? Well, you build a really big radio telescope and point it at the stars. But say if ET isn't transmitting? Say if ET is transmitting, but they are too far away? What if our alien neighbors decided not to transmit radio waves? What if they're just shy and don't want the cosmos to know where they live?

The biggest limitation when trying to listen into any kind of signal is the speed of light. After all, mankind has only been transmitting radio waves for about 100 years. This means that any signal we've accidentally leaked into space has only travelled 100 light years. In galactic scales, this is very pedestrian; the Milky Way is 100,000 light years in diameter and 1,000 light years thick. Only a small handful of stars have had the pleasure of listening into our noise.

There are a few other ways we can go about searching for intelligent extraterrestrials (such as looking for observational evidence of alien mega-structures), but so far we have had little indication that intelligent life lives anywhere else apart from Earth. The Universe is a huge place, it would be naive ...

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