[hoorayimhelping]

Yes. But even more than seeing their space junk, we would have seen evidence of them being on earth in the ground. Civilization changes nature, and when looking through nature, it's very easy to see evidence of civilization. It doesn't look like anything else in nature - right angles, straight lines, clean dividing boundaries, and layers of non-natural debris and junk in the fossil record. There is very clear evidence of a massive asteroid impact 65 million years ago, because there is a layer of iridium in the fossil record that didn't exist before and wasn't natural. In 65 million years, evidence of us being here will be expressed in the fossil record as a layer of hydrocarbons (maybe residue from concrete and steel) from all the hydrocarbons we've pulled out of the earth and released back into the environment.

It's fun to think about civilizations coming before us, but we're the first terrans to reach the level of technical sophistication so that we can change the world on a global scale. Period.

[gdubs]

NASA scientists published a study on this. It’s not as straightforward as one might think:

https://www.theatlantic.com/science/archive/2018/04/are-we-e...

Link to original paper within the article.

[goda90]

Couldn't it be possible there are layers that we've explained as having natural causes simply because when discovered, those attempting to explain them didn't even consider the idea it was caused by a civilization? We're already seeing life adapt to plastics with enzymes that break them down. Perhaps the layer we leave will look more natural than we're assuming.