Laser Launch into Orbit

Yeah that’s a fantastically deep site. After reading the torch ship chapter I’ve come to the conclusion that we either are alone in the observable universe or we’ll be forever bound to our solar system, because we’d see fusion drive signatures on sky surveying telescopes if both are false.

Or, we're missing some corner of physics that allows for interstellar travel that doesn't leave obvious signatures (or misunderstanding a signature that is present).

The Fermi argument effectively puts the kibosh to scenarios where aliens are abundant and interstellar travel is easy.

we're probably alone, though: https://arxiv.org/abs/1806.02404