Aliens ( Archived) (29)

Why do people arrogantly assume that we are not the first sentient life forms in the universe? Then again, there are plenty of people who arrogantly assume the universe was made for humans.

As for abiogenesis (life forming out of inanimate chemicals) on other planets happening the same way it did on ours, it's nearly inevitable one waits long enough. But that doesn't mean it has happened or has to happen.

Think of it as coin flipping. If you flip a coin four times, the chances of four heads in a row is 1/16. If you flip a coin twenty times, the chances of four heads in a row is more than 50%. If you flip the coin 1000 times, the chance of four heads in a row is better than 90%.

For life to occur is like flipping a million heads in a row out of an infinite number of flips. It is possible that it will never happen again (since it did happen once, on Earth), but the chance of it happening grows as the number of flips increases. Or in the case of the universe, as its size and number of stars and planets grows. The Earth is a lucky occurrence, with life happening early, only around 1.5 billion years after its formation, which was around 10 billion years after the Big Bang.

And for those who talk about life, it doesn't mean the life has to know how to speak, let alone travel in space. Proteins are alive, and they don't even have DNA; the simplest living organisms on Earth have only around 40,000 atoms, not the roughly 10^25 atoms (10,000,000,000,000,000,000,000,000) that a human adult has.

And no, I don't believe space aliens have visited the Earth. Even if they exist, the distances involved and the energy required to travel that distance make highly improbable.