Reply #28: One Thing Estimates of Alien Lift Often Don't Take into Account [View All]

[On the Road]

is that the sun is a third-generation star. During the first generation, the universe was almost completely hydrogen. Heavier elements were formed from the first two generations of stars. Therefore, the age of the earth is a better estimate (5 billion years) for the beginnings of life than the age of the universe (14 billion).

Then you have to take into account the time required for life to evolve. If humans are any indication, intelligent life is so complex that it's unlikely it could develop in significantly less time. So I would think that other life forms are developing pretty much on the same time scale, perhaps more slowly. A few million years off, maybe, but not a few billion.

The other thing to take into account is that, if there are other civilizations, we won't be able to see them unless they have created technology on a scale which would be detectable from light-years away, which I'm not even sure humans have developed yet.

And if their technology is detectable at a distance, they would have to be close enough for light or energy to have travelled here. The light from all those distant galaxies is many billions of years old, and unlikely to contain evidence of advanced civilizations.

None of this discounts the idea of extraterrestrial life. But it does suggest it's less likely to be detected anytime soon.