Tag Archives: extra-solar

Is there intelligent life elsewhere in the galaxy?

Is there intelligent life elsewhere in the Universe?  The topic was in the news this week when astronomers at UC Berkeley and University of Hawaii released this report.  These scientists say that about 20% of sun-like stars have earth-sized planets in their habitable zones, the zone where liquid water can exist on the surface of the planet.  Since sun-like stars comprise about 20% of the 200 billion stars in our Milky Way galaxy, some 8 billion earth-sized planets in habitable zones may exist in our galaxy alone! Actually quite more than that, since six percent of red dwarf stars have habitable, Earth-sized planets. and red dwarf stars are the most common stars in our galaxy.  So we’re talking potentially tens of billions of habitable earth-sized planets in our galaxy!

How many extra-solar civilizations could there be in our galaxy?  The Drake Equation gives us a good plan for finding out, even if it doesn’t actually answer the question:

Drake Equation
Drake Equation, composed by astronomer Frank Drake in 1961.



N = is the number of detectable civilizations in our galaxy.

This TED video that explains the rest of the equation and its implications:


The number of such intelligent, communicative civilizations out there might be on the order of magnitude of the length of time the average such civilization exists.  That might not bode well for the possibility of eventually communicating with these civilizations…

Stay tuned.