If say a Martian sentient life had developed and reached a technological level similar to Earths of today, would we be able to detect remains of that today? Presume that we have the ability to send Astronauts to Mars with the necessary equipment. Or would, due to the passage of time, nothing remain which could be unquestioningly be artificial in origin.?
I don’t have an answer to the OP’s actual question, but I want to remark that there were apparently only 500 million years between the atmosphere’s formation and its disappearance, which leaves not nearly enough time for evolution to do much past the single cell stage, much less for civilizations to develop. But that shouldn’t control the discussion, as it would be fighting the hypothetical.
If our civilization were cut short, how much of it would remain after several billion years? I’m guessing some mines/quarries or much-eroded pyramids . . . though even those may be destroyed due to geological events.
It depends on what you mean by ‘similar’. If they somehow developed an advanced society based entirely on soft biological materials (for example, all of their tools, structures, artifacts were no more substantial than a jellyfish, and all existed on or near the surface of the ocean), they might be hard to find - and once found, hard to recognise as a sentient society.
But if by ‘similar’ you mean that they had fire, refined metals, used tools, carved stone, synthesised plastics; built electronic devices, etc - there would have to be something left to find.
Not obvious. It happens that on Earth, multicellular life took a really, really long time to appear, but when it did, it exploded in all directions. There’s no particular reason why this step would take such a long time, so multicellular life could perfectly have appeared very quickly on Mars.
And from multicellular to intelligent life, same thing : it could be incedibly unlikely that it appears at all, or it could be extremely unlikely to not appear quickly after the multicellular stage.
By the way, there was once a thread about aliens visiting the Earth a very long time after the extinction of humanity and whether they’d be able to easily detect traces of the existence of this past civilization. IIRC, the overall answer was that no, after so much time it would very difficult to notice anything.
After billions of years, it seems to me it would be nearly impossible to establish. But maybe Mars is tectonically much less active than the Earth (still, billions of years. What trace could possibly survive that long?)
We’ve found fossils of soft-bodied organisms here on Earth that are at least as old as that
At least some of the tools and artifacts we make are more materially durable than soft-bodied organisms
So in a billion years hence, it should be possible to find at least fossil traces of, I dunno, Barbie dolls or Rolex watches.
In fact, what we might call the ultimate recycling time for the Earth is less than a billion years. That is, each year each piece of matter on each tectonic plate on Earth moves about one inch. The matter of a plate doesn’t just stay the same. Each piece of it arises from the lower layers of the Earth and moves across the plate. It takes less than a billion years to move from one side to another. If a civilization fell apart, after a billion years nothing whatsoever of it would be left.
That’s only correct if this process happens uniformly across all landmasses and uniformly for any given landmass across the span of that billion years, which clearly it doesn’t, as we have examples of fossils much older than that.
The science-fiction books ‘Mars’ and ‘Return to Mars’ by Ben Bova may interest the OP. I don’t want to give too much away because unraveling the mystery is the main draw of the story but I found them fairly interesting and readable.
