[the_af]

> Why do you believe that our current understanding of physics is the final one?

It doesn't have to be final, it just has to be reasonably descriptive of reality.

Even if we review our understanding, the universe is still a massive place and humanity's existence a mere blip. It becomes more about statistics and probability than physics, but yeah, our understanding of physics also makes ETs visiting Earth very unlikely.

If you mean to say "a major revision of physics would make it more feasible", I don't know. Maybe? Or maybe even less feasible! We have to approach this rationally, and so far reason and evidence both lean to "extremely unlikely".

> Let me propose a thought experiment [...] Would you be surprised to learn that relativity, and the limits it imposes, are viewed by those future humans as anachronistic and silly?

As a thought experiment it's a decent piece of science fiction, but as any sort of serious thought it seems like begging the question to me.

[revscat]

> It doesn't have to be final, it just has to be reasonably descriptive of reality.

Which it only is if you limit cosmology to spectroscopy and ignore UAP. If you start to examine UAP as a real thing, and ask questions about “how”, then it all falls apart.

Which is exciting.

[the_af]

I don't think that's true, or at least, you're jumping prematurely to conclusions and sort of begging the question too.

The "U" just means "unidentified", not "contradicting our understanding of physics" or "extraterrestrial intelligence".

There are many life forms on Earth that remain unidentified by many estimations, and we keep discovering new organisms. "Unidentified" doesn't have to violate our understanding of the universe.

[revscat]

But if it does, then our understanding is wrong. That means there are new things to discover.

One of the common reported characteristics of some UAP is that they are able to accelerate hypersonic speeds without a sonic boom.

If that is true then there are things to be learned here. You appear to be saying that this obviously cannot be true because it violates what we currently know.

I think that is tragically unscientific.

[the_af]

> But if it does, then our understanding is wrong. That means there are new things to discover.

That's a big "if". If magic exists, then maybe Gandalf is real.

That there are new things to discover there is no doubt. I don't know how it relates to your need to believe in ETs visiting Earth, but rest assured we have plenty of things to discover about the universe. Most things we will never know.

> One of the common reported characteristics of some UAP is that they are able to accelerate hypersonic speeds without a sonic boom.

> I think that is tragically unscientific.

What's tragically unscientific is cherry picking reports (sometimes by people who are not even claiming the final implication you'd like), disregarding the obvious implications (hoax, liars, top secret military tech, etc) and jumping to conclusions.

What's tragically unscientific is not understanding the scientific method and that extraordinary claims require extraordinary evidence.