Is it possible aliens came to Earth millions of years ago?

I agree with Geoff and would also like to add the fact that if I were an intelligent Alien, I damn sure wouldn't head for the back woods to a little mudball like Earth when the center of the galaxy is where it's happening. Then you have Logan that doesn't seem to understand that the "Hysteria" channel only puts on boobs who have NO expertise in the matter like Giorgio Tsoukalos and Bill Birnes to raise the ratings. I'd also like to ask Logan to post some links where any reputable archaeologist EVER made any such claim. Finally, I'd point out to him that the pyramids line up with EVERY see-able galaxy at some point or other. As if Aliens are going to come here to stack piles of rocks and doodle crop circles. Only someone with a complete lack of common sense would believe that. There is not one drop of proof Aliens have EVER visited here Logan. Do some TRUTHFUL research on the matter.

Remotely possible, yes, but very, very, very, very, very unlikely.

You don't just move around the universe at will. The distances between planets and stars is vast and requires enormous amounts of time to travel, even at light speed. Aliens on the other side of our own galaxy would have a trip time of 75,000 years or so ... at light speed to reach us. How many life forms, even amazing ones would travel for this period of time? Further, that alien would have had to have a good reason to visit ... so it's not likely they would have a good reason millions of years ago.

Sure, some astonishing technology they may have developed ... but we do know something about physics, and it just seems so unlikely.

Extremely unlikely. The monolithic monuments are definitely stone age technology. Stone can be precisely milled with just sand and wood blocks which are thrown away as they wear out. A perfect straight edge can be achieved by folding a flexible material in half, a perfect right angle can be achieved by folding yet again, indeed that's why drafts man have those triangle sets from which they can formulate and angle of 5 degrees increment. Regular repeating patterns can be done with a jig and missing metal brackets are an indication of using a metal that corrodes such as wrought iron instead of something like stainless steel. There's nothing in our DNA to suggest we were modified versus other creatures on Earth.

Besides, we've had supposed UFO reports for how many years, decades, centuries, wouldn't you expect them to have improve their space ships significantly over all those years? Even a generation ship would continually improve their systems.

No.

The thing is, we know how long it has taken life to reach the point where going into space was possible. (roughly 4.5 billion years), and the universe has been around for only about 14 billion years. Our sun is a third-generation star, and it would take a third generation star to have enough elements to make life feasible. From observations, it looks like third generation stars are about the same age as our sun, or younger by a billion years or so.

Assuming that life exists on some of those stars, it would probably take about the same length of time (as we count it) to get to the same state of civilisation as we are, give or take a millennium or so. Thus, the likelihood of finding alien civilisations much older than ours becomes vanishingly small.

Then, there's the travel time between stars, and the energy requirements to make it happen. So, in reality, the possible becomes zero. They'd still be on their way here...

Yes,they came ,they saw,they did,they left.

There is ample proof in ancient civilisations that aliens have been on Earth.

The religious world doesnt want to believe it, as it will ruin all there beliefs.

God,and many gods came to Earth.These aliens,were worshipped as gods.

Sure it's possible. Although unlikely, there is no particular reason that a nearby planet couldn't have developed intelligent life which developed the capacity for interstellar travel, and that this species visited Earth.

But we have absolutely no credible evidence that they did, or even that such a civilization exists, and given a lack of evidence in favor of something, the most sensible thing to do is to assume it didn't happen.

Since the universe is about 12 billion years old it could be possible. But highly unlikely

I think they got here about 250 years ago and formed the Congress of the united States of America.

If you ever watched the aliens segment on the History channel there is prove that aliens could have landed on earth even thousands of years ago. Even to this day, there are remote places on Earth that confound people, some people see ufo's fly into the ocean, or near a mountain etc... Scientists, archeologists, astronomers are even saying now that the pyramids in egypt and the tombs inside of them they think that aliens helped build those monuments by depicting the hyrogliphs on the texts of how to build the stuff in there. Also the pyramids are aligned with the Orion Galaxy, some astronomers have found out, maybe it was aliens doing that on purpose? Who knows. But there are tons of things out there, thats on this earth that cannot be explained about how monuments were built, or items archeologists have discovered that our civilization could not have possibly have the knowledge to build.. Interesting things out there if you research it.

yes. they can only live our atmosphere for a short period of time. we here on earth go to school to learn how to improve what we know exist, so we can continue living as the people who lived before us. When we consume what we think is good for us, not what other people say is good for us, we then become alien. When we become alien, we start looking for ways to find what we think is good for us to consume, so, we end up withering away cause we cannot own up to admitting we are wrong for what we consume, when we were told it is not good for us.

I agree with patman. the discovery channel is food for thought. Since what is said about the universe on that show cannot be proven, people ask what good is it. so the good is, when you watch the show, if you disagree with it, you may get upset cause you are asking yourself what are you watching this for. when you can not come up with an answer, you might pop a blood vessel in your brain, and have big problems. So, some people just make up a story about the universe, see the show on tv for what it is, just like going to the movies, it is all made up so we can see if we like what we are watching. I watch the show to see if i can comprehend how we came into existence, so, once i come up with my conclusion, I can free my mind to think of something else i want to under stand. so, what patman said is true, the show is like hollywood, all made up. Lucky for us all that, things that are made up like that, is the best made up story. it inspires people to get into school and understand what they want to be in life, and are taught what to eat, and exercise to keep healthy, as well as what other people have done in life to bring us to the point we are to-day, make up a story once you pass the test of the story that other people make up, such as dig a hole, and you should find dirt. drink water for thirst once the water is purified. sleep in a warm bed, that was provided to us from people who went to school who learn how to mix what exist so we can have the items we see and consume each day.