Where Are All the Aliens?

'For every grain of sand on Earth, there are 10,000 stars out there.'


Sat, Jun 28th, 2014 21:00 by capnasty NEWS

The Wait But Why site looks at the Fermi Paradox, that reaction when you look up at a clear night sky and see all the stars -- really see them, not blinded by light pollution -- and you ask yourself where is everybody?

Let’s imagine that after billions of years in existence, 1% of Earth-like planets develop life (if that’s true, every grain of sand would represent one planet with life on it). And imagine that on 1% of those planets, the life advances to an intelligent level like it did here on Earth. That would mean there were 10 quadrillion, or 10 million billion intelligent civilizations in the observable universe.

Moving back to just our galaxy, and doing the same math on the lowest estimate for stars in the Milky Way (100 billion), we’d estimate that there are 1 billion Earth-like planets and 100,000 intelligent civilizations in our galaxy.

SETI (Search for Extraterrestrial Intelligence) is an organization dedicated to listening for signals from other intelligent life. If we’re right that there are 100,000 or more intelligent civilizations in our galaxy, and even a fraction of them are sending out radio waves or laser beams or other modes of attempting to contact others, shouldn’t SETI’s satellite array pick up all kinds of signals?

But it hasn’t. Not one. Ever.

Where is everybody?



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