While we're on the topic of nuclear pollution, "nuclear semiotics" is an interdisciplinary field of research focused on creating a "warning message intended to deter human intrusion at nuclear waste repositories in the far future, within or above the order of magnitude of 10,000 years."

While 10K is a few orders of magnitude greater than 500, I imagine the problems may be similar... if not more extreme.

Source: https://en.wikipedia.org/wiki/Long-time_nuclear_waste_warnin...

I haven't seen the article, but I don't buy it, there's no likely events that will harm Voyager 1 and 2 in that time period, for instance. They could get really unluckly and hit a star/planet, but it's not at all likely. Along a similar vein many of the satellites that we put in graveyard orbits around earth at the end of their useful life will also plausibly last that long, though there is a lot more debris for them to collide with.

We've also certainly... redistributed... many metals and other things around earth. Perhaps "large concentration of iron over what use to be new york" doesn't count, but arguably it should.

My favorite weird theory is the "Siluran hypothesis," which states that our industrial revolution was not the first. There are some events in sediment that look like what our industrial revolution will look like. (many millions of years ago, so yes, reptiles)

"Thou shalt not violate causality in my historic light cone," I believe.

Ah yes, that was it.

But it wasn't just the act of creating some clay tablets - those particular clay tablets happen to have run the probability gauntlet successfully and came out the other side - just making a clay tablet and putting it in your closet is unlikely to produce the same results. The place you put the tablet is more important than the fact that it's a clay tablet in itself.

The things listed there are completely worthless though. In case of system collapse I'd want to know practical things like agriculture and simple power plants.

The claim is usually that diamond is the hardest material, which for the most part it is.

Strength is usually defined by the application and usually focuses on tensile / compressive strength. This is also why rebar is used in concrete, concrete has excellent compressive strength, but poor tensile strength.

There's lots of metrics for strength, also resistance to fatigue is often an important metric.

Diamond has excellent hardness, and compressive strength (diamond anvils), it's very poor in most other metrics of strength and evaporates above 450 degrees, so it's not good for anything hot.