Long term evidence of civilization.

[ewmayer]

Originally Posted by xilman

We should be careful to draw distinctions between intelligence, civilization and high technology.

Taking just our own species for an example, we have been intelligent for many millennia and civilised (in the sense of building cities, efficient information systems, sophisticated economys, etc) for about 5000 years. We've had high technology for about 300 years. Biological, nuclear or nanotechnology warfare could wipe us out in short order. Our existence would be obvious for 10K years perhaps 100K. After 100M years it would take a great deal of effort by high-tech supported paleontologists to find suggestive clues of our existence and that evidence would be highly disputed. Extraordinary claims require extraordinary evidence.

For all I know, there could have been a civilization in existence 66.5M years ago but they didn't build their industrial base and planetary defence systems soon enough.

You're putting words in my mouth - I said nothing about modern-style hi-tech, I described civilizations as "[large] aggregates of intelligent creatures with significant social organization, and thus, ability to shape and exploit their environment and engage in far-flung economic-trade relationships in ways which leave unmistakeable long-term traces." The great ancient civilizations which sprang up in the millenia after mankind began large-scale agriculture (which implies both a switch from nomadic hunter-gatherer to sessile, and agricultural surpluses which free people's time up to devote to 'higher' pursuits) all did those things, and the remains are all over the place. Sure, another couple million years will bury/obscure most of them, but even if the Egyptian pyramids have been worn down to low stumps by then, the lower parts buried in sand will remain as obvious markers of civilization. If we can find fossils ranging from tiny pollen grains to T.Rex skeletons 100 million years later, a future race of similar intelligence will bloody well be able to find giant square bases of huge former pyramidal stone structures buried in sand.

As to your last "for all I know" bit, you again ignore the where-are-the-bones aspect, as we have a very well-populated fossil record going back that far, which includes tiny mouse-sized creatures now believed to be our ancestors. Or are you positing some hypothetical race of gelatinous creatures which somehow lived on the surface of the earth, evaded the saurian predators which dominated more or less all Earth's surface and were able to build a complex civilization which left no traces, not even pottery-shard-like ones? If we're talking about extraordinary claims which require extraordinary evidence, yours is it, not mine.

[xilman]

Originally Posted by ewmayer

Or are you positing some hypothetical race of gelatinous creatures which somehow lived on the surface of the earth, evaded the saurian predators which dominated more or less all Earth's surface and were able to build a complex civilization which left no traces, not even pottery-shard-like ones? If we're talking about extraordinary claims which require extraordinary evidence, yours is it, not mine.

Octopodes are smart and gelatinous. They are not, yet, social animals, but their ancestors may have been in the past.

I see no reason why a civilization has to inhabit the land any more than we inhabit the oceans.

As for our Cretaceous ancestors, very little fossil evidence survives from the Purgatorius genus and it's not even certain that they were primates at all. IIRC the fossils are a few teeth and a leg skeletion.

[xilman]

[QUOTE=ewmayer;547998]f we can find fossils ranging from tiny pollen grains to T.Rex skeletons 100 million years later, a future race of similar intelligence will bloody well be able to find giant square bases of huge former pyramidal stone structures buried in sand./QUOTE]

Pollen from wind pollinated plants (ferns, conifers, grasses, etc) is a particularly easy substance to find. It is produced in vast quantities, spread over a large area (so more likely to find a suitable place to be fossilised) and is structurally tough. Carbonate shells of marine molluscs have much the same qualities and their fossils are also easy to find.

[The Carnivore]

Originally Posted by Nick

And are we missing the signs of a civilization before ours?

That reminds me of this:
https://medium.com/swlh/the-silurian...s-3f8828a61266

It's a somewhat long but interesting read.

[The Carnivore]

Originally Posted by xilman

Give it another 100M years and I suspect that the only clear evidence for our technological civilization will be geological evidence of a simultaneous and sudden increase in atmospheric CO₂ levels, a mass extinction event, and a global distribution of wheat, rice and maize pollen. Even those signals would be hotly debated.

As mentioned in another thread, don't forget the chicken bones:
https://www.mersenneforum.org/showth...694#post504694

Originally Posted by xilman

In the long run, everything is dead.

If stars burning all their hydrogen doesn't get you, proton decay will.

Welcome to the real universe.

The jury is still out on whether parallel universes exist, or whether it's possible to travel to them or to obtain anything from them. It may also be possible to time-travel to the past when entropy was lower and the stars haven't burned out yet, provided that you don't travel back before the instant that the time machine was created.

Perhaps a future civilization or species somewhere in the universe will eventually figure it out.

[xilman]

Originally Posted by retina

I expect that would require a (much) larger brain case than we currently see in the fossil evidence.

I have already commented on the "large" portion of your statement, giving African Grey parrots as an example.

Re-reading this thread lead me to realise that I should also have addressed teh "case" portion.

Consider octopodes.

[LaurV]

Originally Posted by xilman

Consider octopodes.

Those are octopuses which can speak German language (DE, Deutsch).

[retina]

Originally Posted by xilman

I have already commented on the "large" portion of your statement, giving African Grey parrots as an example.

Re-reading this thread lead me to realise that I should also have addressed teh "case" portion.

Consider octopodes.

Would you consider that sheep have their own civilisation? They all hang around together, doing the same things together. And just like most humans they follow the latest trends (apparently) without thinking about where it leads.

[TommyJ]

Originally Posted by retina

Would you consider that sheep have their own civilisation? They all hang around together, doing the same things together. And just like most humans they follow the latest trends (apparently) without thinking about where it leads.

I wonder if humanity is an intelligent life form.
We cannot agree among ourselves on the little things.
But nevertheless, we make guesses and plans.
Quite often, we come across news that scientists assume that they have found some form of life.
Usually, it is water or phosphine or something like that.
But globally, like the sheep in your example, we may be unable to understand another intelligent life form. And this seems to be the main reason why we cannot find it.
Precisely because we do not know what long-term traces to look for.

[Uncwilly]

Originally Posted by TommyJ

Quite often, we come across news that scientists assume that they have found some form of life.
Usually, it is water or phosphine or something like that.

You mean reporters that are not full time science reporters proclaim "WE FOUND possible EVIDENCE OF LIFE"

[firejuggler]

if you find a nuclear reactor waste site , you may have found the last remain of a civilisation.