[MikeSid]

I have no problem believing that there has been, and for a long time, a covert US government program to collect wreckage from unidentified anomalous phenomena. And I would suspect that all items collected have a terrestrial origin. After all, how could anyone ever say that something was not from this planet? We discover new things all the time. That doesn't mean that something we don't recognize is from another world. Did it have a label on it, "Made on the 3rd planet from Alpha Centuri"?

There is sufficient evidence that the US government has kept technological secrets for many decades. I think many governments being successful in keeping those sorts of secrets is achievable and such occurring in the past is probably easily provable, if not a complete given.

But....and here's where the rubber meets the road.... if any single human laid eyes on something that was conclusive evidence of a extra terrestrial lifeform or intelligence, the discovery would be of such monumental significance to humanity that the secret simply could not be kept. Coming to grips with that sort of proof would shake any individual to the core. Imagine being that guy and keeping a lid on it. No measure of stigmata would keep you silent. And you could recount exactly what you saw - 1st hand, in detail. And finally, who would be able to silence you? Anyone you report to would demand to see the proof you saw, and they'd instantly be in the same boat. It is simply a secret that could not be kept.

So put me in the camp that believes the government has recovered a lot of weird and wild stuff, and that we don't know where it came from, but none of it can be said with certainty to be from another world.

There was a long time poster here that checked out a while back and his signature block said, "If time travel were ever to exist it already does." I think the same can be said of interstellar travel. No species has evolved to that point without an extinction event. I don't believe we'll get there either. And it may be a self-limiting thing. Perhaps the technological advancements necessary to achieve interstellar travel play a not-insignificant role in an intelligent species' extinction. And it's not like interstellar species can learn from the mistakes of others if they can't get there to learn.