Could very ancient advanced intelligent terrestrial life have existed?

Anything is possible. Even things for which there is no evidence. They just aren’t very likely.

It’s a quite common theory among sceptics, that things like the Egyptian pyramids and Sphinx were built by aliens, or at least aliens came and gave them the technology and knowledge to build such structures. They were referred to as the “gods” in many ancient texts. Though there is very little evidence for such theories.

The current best estimates put the age of the Earth at 4.5 billion years. The oldest fossils to date are approximately 3.5 billion years old (i.e. life forms that would have appeared soon after the asteroid bombardment). So the hypothesis raised in your question would require that life evolve from single cells to technically advanced forms in less than 1 billion years, or about one fourth the time that it has taken us to evolve. I’m gonna say no.

“Within the past few billion years could another race of highly advanced intelligent life have lived here and become extinct leaving no trace?

If so would we have found clues to such an existence?”

On balance of probability, no: your own reasoning tells you why.

@Keep_on_running – you should be clear on your definition of “sceptic” as one who “doubts accepted opinions or beliefs”, rather than as one who “doubts assertions until they are supported with evidence”. Graham Hancock, for example, is not a sceptic in my book.

@the100thmonkey I agree, probably not the best choice of words.

From what I gather here, it anything that can’t be measure, touched, or seen, doesn’t exist. Homo Sapiens is the top dog and only sentient being around. Live here was just luck. Wining the primordial lotto,

Define “advanced”.

My guess is no. We see with complex civilizations, particularly highly technological ones, that they always end in resource drawdown, then overshoot, then collapse.

@Keep_on_running That’s the plot to Stargate, not reputable theory.

@incendiary_dan That’s cool. Still quite interesting.

Makes me wonder though how they were able to carry 2 million or so blocks weighing 2 or more tonnes each into a perfectly symmetrical structure.

@Hypocrisy_Central – that’s a little unfair, although I don’t think it uncharacteristic.

Why can’t we all have magic?

@Keep_on_running It was done over many years, rolling them on timber rollers, pushing them on ramped scaffolding, and with many thousands of slaves. This has been replicated on small scale a few times (obviously without the slaves).

I understand that is the currently accepted explanation ;)

I doubt think it’s very likely. As far as I know we do not see a train of evidence in the fossil record towards anything with hands well-adapted to tool making, bar us. Are there gaps in the record? Certainly. But tool making doesn’t just happen overnight. I would think that we would at least know of a “getting close” species (say like chimps viz-a-viz us) if a civilization had indeed cropped on Earth. I can’t think of an example (but then I am not a paleontologist).

Depends on what they were advanced at, and what evidence they would or would not have left. That is to say, yes it’s possible, unless you mean something that would have left evidence that we would have found some trace of.