Nathan Taylor reminds us:
A new paper using data from NASA’s Kepler telescope came out recently, estimating that 22% of Sun-like stars harbor Earth-sized planets. This is a big increase over previous estimates. It’s very cool work. Love it. But the news spin was predictable…
The existence of extraterrestrial intelligence (henceforth ETIs, or just ETs) is normally discussed in the context of the Fermi Paradox, which Wikipedia describes as “the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilization and humanity’s lack of contact with, or evidence for, such civilizations.” Now I’m a strong advocate for there being no ETs in our galaxy, as explained in this recent post. In fact I’ve gotten so tired of hearing about ETs I’ve started thinking of it as “Carl Sagan Syndrome.”
…Recall from my previous post how we have three wildly disparate time scales in play: millions, billions and trillions. Rounding to the nearest 20, we have:
- Time for intelligent life to fill a galaxy: super short 20 million years
- Time for intelligent life to evolve in a galaxy: moderate 20 billion years
- Time of universe to keep having stars: super long 20 trillion years
The first perspective shift is to step back in time, and realize the universe is very young. With 20 trillion years of star generation ahead, the universe has only covered 13.7 billion years or roughly .07% of its life span. Compare this to a person who expects to live 70 years, and you’d get .07% * 70 years = roughly 18 days. So in human terms the universe is a three week old baby. No wonder there’s not too much life out there yet.