EVIDENCE... for what?

We do not know how to travel at 80% of the speed of light.

Oh, it is possible. Nothing in our science, nothing in our
physics says it's impossible. Nothing within our knowledge
rules it out as a possibility. But, we do not know how to
tvael at 80% of the speed of light.

We can do it, as far as we know, it does lie within the
realm of possibilities but, we don't know how.

It's a tough problem, traveling at 80% of the speed of
light, a lot of things we'd need to figure out.

Some form of propulsion that can get us that fast.. energy
and/or fuel to run the engines... DOUBLED, because we'd
need exactly as much to bring us to a stop once we get to
where we're going...

Never mind an interstellar comet or meteorite, a rock, a
pebble at those velocities would vaporize our ship. We'd
need a solution for that, how to protect us from debris...

So there's a lot to work out before we'd be capable of
traveling at 80% of the speed of light, and everything tells
us that it's possible and nothing tells us that it's
impossible.

This is not the case with the speed of light.

As far as what we know, our physics, all of sciences tells
us that NOBODY and NOTHING can exceed light speed, or even
reach it.

"We don't know" does NOT apply to everything equally. In
the case of the speed of light, we do know. To the best of
our knowledge, according to our science, our phsyics it's
impossible.



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