David Kipping

And you've heard the Cerulean hypothesis, this idea that could have been like a past civilization.

Maybe the dinosaurs, for instance, could have had like technology and civilization.

I've never heard that.

Adam Frank, he was on here a few years ago.

Maybe it was before he came up with this idea.

But yeah, he has this fun idea called the Cerulean Hypothesis.

It's kind of borrowed from sci-fi.

I think the word's Cerulean or Silurian.

Not sure how to say it.

But yeah, he had this idea that maybe there was someone 50 million years ago on this planet, a civilization.

And over that time scale, a lot of it does, as you correctly say, get eroded.

It's really difficult to put strong limits on them.

But I think at the stage we're at now, with the amount of plastic and concrete we've made, and also just having stuff on the moon, right?

There's nothing else.

We've imaged the moon every centimeter of that damn thing.

There's no other stuff on the surface except for what we've put there.

So at this point, we can be pretty confident there was never a space age civilization in the past, despite the fact there appear to be opportunities.

And so maybe the emergence of civilization requires just the right conditions in some certain way.

But then it is spooky that it happened now.

It's like when you talk to a World War I veteran.