How Far Away Is Intelligent Life In the Universe?

Artistic imagining of Kepler-22b
Credit: Reuters/NASA/JPL-Cal Tech

Scientists announced the discovery this week of Kepler-22b, the most Earth-like planet ever detected.

Kepler-22b is similar in size to the Earth (astronomically speaking at least) and it orbits a sun-like star from what is considered to be a habitable distance, an indication that temperatures are likely neither boiling hot nor tundra cold on the planet's surface.

To sustain life in the way that we have done on earth, a planet must be in the "habitable zone," with a climate that allows for the existence of liquid water on the planet's surface. Kepler-22b meets the habitable distance criteria, and if it were found to have a surface and atmosphere similar to ours, scientists estimate temperatures in the comfortable 70 degree range.

This is all very exciting for scientists and for the fervent "I want to believe" community. I don't belong to either of those groups (although I am more likely to join SETI to listen for aliens than I am to become a scientist at this point in my life), but the discovery of Kepler-22b peaked my imagination and I decided to have a little fun with it.

Primordial Soup
(artist rendering not an actual photo)

If we take the little science we know about Kepler-22b a couple of steps further, it's fair to say that the planet could meet all of our habitable criteria. Then, let's assume that biological evolution in Kepler-22b's primordial soup has occurred on a parallel track to the way science theorizes that it happened on Earth. Depending on where Kepler falls on the evolutionary timeline, there could already be humanesque life on the planet, albeit possibly only Cro-Magnon types, or perhaps advanced far beyond us.

Working from the assumption that intelligent life might well have evolved on Kepler-22b (or whatever the Keplerians call their planet), and being a naturally gregarious and sociable type, my next logical question was - how long would it take us to get there to say hello?

Kepler-22b is an estimated 600 light years away. That means if we could travel as fast as a beam of light, it would take about 600 years. So, I researched our current fastest spacecraft to see how close we were getting to that kind of speed. What I found was a bit discouraging.