Just passing some time

Suppose a species arises in a planet and forms a civilization. say this endures for 15,000 years, progressing from cave dwellers to, eventually, builders of skyscrapers and large cities. Then one day the civilization dies out in some catastrophe, let's say a massive asteroid or comet strike. Every sentient being dies in a few years, but other life-forms manage to survive (though not many).

Now let's say we find this planet 50 million years after this catastrophe. Would we find any trace of this long, long dead civilization?

Everything would have decayed, from cave paintings to mile-high buildings. Their mighty cities would crumble, then be buried and compressed under layer upon layer of soil and rock and water. So there's no question you'd get there and find standing structures. But, absent orbiting satellites, some of which could last that long depending on their orbits, could you find at least some trace?

You'd inevitably find fossilized bones. But what of other things? Would electronic devices fossilize as well? Would pots and pans? Could you find intact dishes or pieces of some? What would become of subway tunnels and sewage systems?

We would find huge traces of this long lost civilization. Plastics will have decomposed. Some glass and metals will not have, so your phones 50,000,000 years from now might consist of glass and metal. Pots and pans will not decompose. Over 50,000,000 years all tunnels and sewage systems will have collapsed, but the metal tracks will remain. Anthopologists in the future would only conclude that some great civilization was here, and they would find the crater to link it all together.

All wood will decompose. Only metal, complex plastics and glass would remain. But the metallic footprint would be huge. Depending on how far things are buried, some metal will be melted and appear as deposits.

I think.

Quote: boymimbo

We would find huge traces of this long lost civilization.

That's what I think.

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Plastics will have decomposed.

Plastics are an odd material. they may fossilize, as they contain loads of carbon molecules.

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Some glass and metals will not have, so your phones 50,000,000 years from now might consist of glass and metal. Pots and pans will not decompose.

Agreed. Some will wear down and disintegrate (otherwise we'd be stumbling over metal tools at every archeological site), or get compressed over time under tons of rock and soil, or rust away,, but think how many billions of pots and pans exist.

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All wood will decompose.

I wonder if furniture or an entire house could be petrified. Imagine that.

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But the metallic footprint would be huge.

I assume several footprints would be huge. Nearly every factory would decay with tons and tons of various raw materials. What becomes of a thousand tons of plastic pellets in that time? Or several tons of steel ingots?

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I think.

There's that.

Perhaps someday we'll find such remains.

I think there's no question that many things will leave a footprint, given nothing more than standard erosion and decomposition. My question would be a geological one. Thinking of many of the most populated areas, your southern Cali, your Japan, how much of that would be sucked under tectonically?

What would survive this mother of all grinders?

Quote: Face

Thinking of many of the most populated areas, your southern Cali, your Japan, how much of that would be sucked under tectonically?

Not as much as you might think. 50 million years is a short time to a planet 4.5 billion years old, after all. The continents would have drifted, yes, but the map might seem recognizable, if distorted, after that much time. Some cities might be swallowed under some subduction zone, never to be seen again, but not all or even most, or even most in seismically active areas.