[cubefox]

> For example we've only found about one dinosaur fossil per 10,000 years of dinosaur history. The dinosaurs were around for a long time, from 65-250 million years ago.

Dinosaurs presumably fossilize very badly compared to many artificial artifacts, like buildings made out of machined stone.

[withinboredom]

Man, I’ve been in castles that are less than a thousand years old that are barely recognizable. Machu pichu is a good one as well.

[inglor_cz]

Castles that stay above ground, yes, but there likely would be some buried structures, too.

Pompeii looked remarkably fresh when dug out.

[withinboredom]

Pompeii was literally buried in a matter of hours, so that’s kind of a unique case. Any underground structures would be turned into a cave from water seeping in. Most people don’t dig into the side of caves, so it’s likely we’d never know. A great example is the millennium old water passages in Afghanistan. You can’t tell they are man made any more.

The point stands, most things don’t survive all that long (in the grand scheme of things). Occasionally, the conditions are exactly right to preserve something, but there is a limit.

[cubefox]

Structures / cities might also get buried within a few hundred years due to overgrowth.

[datavirtue]

Sufficient sized meteorite impact would melt the entire surface of the planet.

[jiggawatts]

That did happen — the Moon is theorised to have formed from the ejecta of a planet-sized impactor.

However, that happened very early in the history of the solar system, likely before life had a chance to start.

[K0balt]

On the timescale we are looking at coastal areas are completely destroyed or created and substantial destruction and renewal of crust occurs. No guarantee of anything being found at all.

[cubefox]

Dinosaur fossils also didn't have a guarantee of being found. It's all in the probability.

[K0balt]

If you flip a fair coin 1000 times I guarantee it comes up heads at least once. If you set a cup on a table I guarantee it won’t pass through the table, even though both the glass and the table are mostly empty space.

Those things also are all in the probability.

[rini17]

Stone does weather too. It either needs uninterrupted dry climate (not really possible for millions of years) or being placed inside a stable geological formation (we don't usually build that way).

[cubefox]

I'd bet stone weathers many orders of magnitude less than dinosaur bones.

[JumpCrisscross]

Fossils are stone. The porous bone that housed the minerals are long gone by the time we find them.

[cubefox]

We are talking about actual bones in living animals though, and those surely fossilize (preserve over eons) much more rarely than many civilizational artifacts.

[JumpCrisscross]

> those surely fossilize (preserve over eons) much more rarely than many civilizational artifacts

I don't think they would fossilise. It's a process specific to the porosity of organic tissue. They might be preserved, but the Cambridge paper explains why it’s unlikely they would last for a hundred millennia or more.

[cubefox]

But surely it is much more unlikely that animal bones would last for a hundred millennia.