That's why so many great discoveries come from digging below the surface of the planet
Well, there exists evidence today that dinosaurs once walked this planet. And we're also pretty sure we know what happened which put an end to their era. So what's that..? 65 million years...?

But on what reasoning you are assuming that they would wanna settle here?Our biology will be completely alien for them, yes even if they breathe the same air and drink the same water, because they will not have sugars, DNA...like we, but their alien equivalent and encounter of these biloogies would cause extreme allergies or even poisionings I think.

And explain to me; why do you think they wouldn't erase traces if they were there.

People, it seems to me here you are trying to appear very smart and sceptical but you are using flawed logic to try to disprove something what we don;'t know anything about.

You make million assumptions completely w/o evidence that can be easily refuted because you can not predict anything about beings from planets thousads of trillion kms from us.

Oh, and you assume that galaxy travelling aliens would bury their bodies under the Earth, provided they even have bodies in a normal sense at all.

Bones can remain, but structures will erode away very fast.

Please tell me where I have made a single assumption about anything relating to this subject. I am 100% open to just about any possibility with regards to this subject. I enjoy theorizing and reading other theories. I have some beliefs, but none that I am married to. Really the only assumption I make when discussing this subject is that human being fit the definition of "intelligent life" (and even that gets argued sometimes).

That said, the only point I was addressing was that of Drunk Vegan, who said "If we all dropped dead today, in a million years (and probably much, much sooner) there would be no evidence that the human race had ever existed." I disagreed with that point and gave an example of a lifeform that dropped dead ~65 million years ago but left evidence lasting to this very day.

With all due respect, you are grossly misrepresenting my words - perhaps deliberately, perhaps not.

RedFive: "many great discoveries come from digging below the surface of the planet "

m1omg: "you assume that galaxy travelling aliens would bury their bodies under the Earth"

My friend, there is just no logical correlation betweern my statement and your interpretation.

We are finding our own ancestors fossils from between 1 and 2 million years ago.

Even after a million years, there would be a layer in the geological strata indicting our civilization- not to mention our having pumped oil out of the Earth and buried toxic waste inside it.

Yes, but because they have bones that we can dig out.

Once Yucca Flats is loaded, there will be a signpost that says "somebody was here" for a long, long, long time!

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Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

What if aliens were on Venus in the past, terraformed it, and then slagged it, for whatever reason, maybe even some secret project?
That would explain both the absence of water, greenhouse effect, slow reverse rotation and the appearance of entire crust being melted 700-500 million years in the past...

Yes, many theories are consistent with the evidence. . . .

So does it matter much which one we choose to believe?

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Fitting a three-parameter curve of uncertain form to ten points with three exceptions certainly brings one to the far edge of the known world. -- Bradley Ephron

If you look at some of the posits of brane and string theory, you'll see that some have theorized that gravity itself is centered on another brane, which is why its so weak compared to the other three fundamental forces. This brane is located in a plane of higher dimensions. I further hypothesize that black holes become powerful enough to tap into this brane and if, as some interpretations of relativity suggest, there is a wormhole on the other side, then we could create a tunnel or a bridge that would let you go thousands of light years in an instant (sort of like tunneling through the earth to get to China.) The famous Cal Tech physicist Kip Thorne mathematically formulated the concept of transversable wormholes that explores this theory.

When the LHC comes online, I think we will begin to tap into the higher energies that are required to confirm these theories. Regardless, I believe that within a few hundred years (500 at most) we'll be at the level of technology where we ourselves can transverse the stars. Even if Im too quick, and its 5000, or even 50000 years (very unlikely) that timespan is miniscule compared to cosmological, even geological time scales (as long as our species doesnt destroy itself...) Just think of what advances our species has made in the last 50 years, let alone 500 or 5000! Any alien civilization that existed in a second generation solar system would have a huge leg up on us.

For decades I have had this feeling that we are indeed alone and that the mystery of existence is so deep and distant that we must somehow get off this planet and begin the unfathomable process of populating the vast out-there because it is going to take us a very long time to understand what it is all about. I have little patience for the world's wars and travails - I want to scream at the madmen - "Get your @#$% together you fools before you wreck perhaps the only chance we shall ever have!"
Then again - back in the early Nineties I had the "feeling" that the Buffalo Bills were going to win a Super Bowl - so. -dayll

But why would they? I'm not satisfied with the answer that they don't want us to know. You are again making assumptions how they think. There's always the possibility they simply don't care.

Of course, in the chain of reasoning that leads to the Fermi Paradox one has to assume that the visiting aliens leave behind lots of evidence (or more generally, alien civilizations should be detectable). Earth could have visited about a zillion times without us knowing if the visitors were careful. But if there are colonizing civilizations (again: only one civilization...), at least one should have selected our Solar System. And then we should be aware of them unless they're want to hide.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

You mean, all evidence of structures have disappeared before bones? You're mistaken. Besides, actual bone tissue is very seldom found; in the fossilization process bones and other organic materials are slowly replaced by minerals.

Aliens have probably some fancy materials we can't even begin to imagine of. If you want a true starfaring civilization, current materials just aren't enough. They have to be very strong and lightweight.

If humans disappear tomorrow, what will stay behind? What material remains intact for a very long period? Organics decay, as do iron; concrete and asphalt erode away. Something hard... and it has to be very common so that at least some survive until the future archaeologists uncover them... I know! Toilet seats!

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Well, the Oklo reactor in Gabon is only two billion years old.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

I think that people who are appalled by the very idea that humans are a true one-off tend to be committed atheists; because if it were the case that humans are the only intelligent species would not that fact tend to favor theism over a materialistic naturalism? (Although, of course, if we were the only intelligent species, that would not be logically inconsistent with materialism.)

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Fitting a three-parameter curve of uncertain form to ten points with three exceptions certainly brings one to the far edge of the known world. -- Bradley Ephron

Personally I'd find humans being the only intelligent life to be strong evidence in favor of atheism. It doesn't seem plausible to create a universe of umpteen quadrillions of stars and planets and only populate one of them.

Well... let's just that if (hypothetically) it were proven that humanity is the only intelligent life in the universe, then there would be an awful lot of people who believe in God saying "I told you so."... But I have to say that, IMHO, I wouldn't consider it good evidence one way or the other.

Our being or not being the only ones here has absolutely zero bearing on any religion's god and/or gods. It just means we won the lottery, nothing more.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort