It actually appeared on Earth very early in Earth's history. But that might be due to panspermia.

There's no evidence of aliens civilizations at all. Whether or not you trust the government or the US government in particular is meaningless. Currently it would take 40K years to travel 1 light year. The closest star system to earth is 4.2 light years away. And there's no evidence of a planet in the habitable zone there. Fermi Paradox perports probability of intelligent life somewhere in the universe. They can't get here and we can't get there. They are no little green men.

@barjoe yeah, I've heard your emphatic statements on this subject before. I don't need a recap.

@David1955 US House of Representative had a ridiculous congressional hearing on UAPs, which is apparently our govt's new name for UFOs. They had 3 "whistleblowers", one David Grusch blatantly lied under oath claiming he saw a non-human pilot of an alien craft. That is a scientific impossibility and our Congress is now a laughing stock. Shameful.

@barjoe I don't know what you're trying to convince me of. I'm just keeping an open mind and seeing what might be revealed. You seem emphatic to convince yourself of your own questionable certainties on the subject, quite frankly.

@David1955 I'm open to credible evidence of intergalactic travel coming to earth. Unfortunately there isn't any.

@barjoe it doesn't sound like it, but I'll give you the benefit of the doubt.

@David1955 Do you have any credible evidence?

@barjoe can't you read? I'm not saying I have evidence; just saying there's a lot of discussion about this subject so I'm keeping an open mind on it, while being wary of UFO freaks on the one hand and lying American agencies ( as if there's any other kind ) on the other.

@David1955 Do you have evidence that United States lied about extraterrestrial visitation? Do you have an open mind that they could be truthful? If some of these UAPs are actual secret government projects, you couldn't expect them to reveal those secrets.

Depends on the odds of it happening. If the odds are low enough, we might well be alone.

@Druvius "Life" is anything more complex than a virus, which itself is borderline.
It could be silicon based even.
However COMPLEX life is a very different matter.

@Druvius As far as evolution of species which led to intelligent life? Within our Galaxy and any "nearby" galaxies, we are likey alone.

@barjoe not necessarily. But if you also throw in time, then here in our galaxy, AND NOW we quite probably are.

@Petter We don't know what was in the last 13.8 billion years or what will be in the future. Our entire existence is a miniscule speck in time.

@barjoe Precisely.

Any intelligent alien species would isolate the earth like in a zoo where the semi intelligent wild animals are cared for but cannot harm the civilised alien worlds.

@vocaloldfart Time. Earth is 4.5 billion years old. Humans have only been here go ½ million years. "They" probably don't exist at all and certainly not at the same time that we exist. If they can observe us from 1 million light years away, we don't exist yet.

@barjoe you have me confused as to what you are trying to say. I cannot understand why aliens have to be 1 million light years way from us, nor can I assume they have the same technology as us at present.
According to archaeology, the Australia aboriginals have showed signs that they were here over 125.00 years ago. their dreamtime stories accurately describe events that happened 250 000 years ago.
All over the world there are stories of mans exploits in religious and history books that are now being questioned and discovered to be a lot older that previously thought and taught. New technological advances are breaking down the misconceptions of the past.
You seem to have your aliens neatly in one box. I however prefer to keep an open mind and make no assumptions at all, just extrapolate from pure logical thinking

@vocaloldfart Do you have any evidence of extraterrestrial visitation in earth? No? I didn't think so.