[avaldez_]

They have to abide by the rules of the universe that WE know of. The universe is unbelievably big but also unfathomably OLD, so I'm sure there's been plenty of time for a number of civilizations to reach a technological level vastly larger than ours. Our latest technological revolution started just a hundred years ago. Imagine what just 10,000 more years can do. I mean, we thought (and our math said so) that the speed of sound was a physical barrier just a _few_ years ago. (https://en.wikipedia.org/wiki/Prandtl%E2%80%93Glauert_singul...)

[Shawnj2]

Not necessarily, from what I heard humanity being alone is actually an extremely plausible solution to the Fermi paradox because we exist close to the beginning of the total lifespan of the universe.

[techbuttman]

The universe is thought to be about 13.8 billion years old. The Earth is about 4.6 billion years old. I don't think humanity has even been around for 500k years.

[Shawnj2]

Yep so life on earth evolved about as early as reasonably possible.

[gorjusborg]

Easy to claim when your sample size is 1/1.

Hard to know for sure.

[Shawnj2]

There are other factors that stop the kind of life we see on earth from appearing earlier in the universe’s history. For example the first stars (the pure hydrogen ones) could not have had planets that supported life and they burned too hot and quick to reasonably do so.