For those concerned about distances... if wormholes exist as theorized, that could explain how one could cover vast distances. In the movie Contact, that’s how Jodie Foster’s character travelled to make contact. The machine either created a new, or opened up access to an existing, wormhole.
But let’s say the solution to Einstein’s equations are wrong and there are no wormholes. Why do we assume all life forms are like us? If a civilization is advanced enough for interstellar travel, presumably their medicine is also advanced. Maybe through regeneration or replacement of body parts, and treating all diseases, other beings can live hundreds or thousands of years. Or maybe they are alien/machine hybrids that allow them much longer lifespans. A species like that could travel across galaxies in a generation or two or three in a large mothership. And since the odds that they are using rockets is virtually nil, sources of energy could be much more sophisticated. Maybe the energy source is the ship itself, which generates more energy as it’s used up, so you don’t need large fuel reserves.
Especially if they have mastered travel at or near the speed of light. Time slows down as you approach the speed of light, relative to objects traveling much slower. So, if you’re traveling near the speed of light, a year in the spaceship could be 10+ years on earth. Combine that with longer lifespans, and suddenly crossing large swaths of space becomes more practical, even without wormholes.
There are a number of things I’ve read/heard over the years that raise interesting questions about our history, if they’re true. There’s supposedly evidence, in India, of nuclear blasts that occurred thousands of years ago. There’s supposedly evidence underwater and in Antarctica of advanced civilizations that existed during the ice age, that were buried when the ice melted and the oceans rose.
More interesting is that some scientists say the asteroid belt exists where a planet should be, if you look at how the planets are arranged. Mars used to have an atmosphere, and probably life. Was there a war between Mars and a neighboring planet that blew one up and ruined the other? On top of that, our circadian rhythm supposedly resets to 23.5 hours in space, instead of 24. Guess how long a day is on Mars? And if we evolved on earth, why are our eyes and skin so sensitive to the sun? It’s almost like we were built for a planet not so close to the sun. Many of the oldest religions and societies, like those of Native Americans and in India, believe our ancestors came from the stars. Then there the supposed incident where NASA did a geological test and it essentially caused the moon to ring for hours. Is the moon artificial and hollow? Life on this planet wouldn’t exist as it does without the moon and it’s affect on the tides, etc. Like I said, I haven’t verified all of this, but, it does make one wonder.
I’ve often wondered, what if we’re just a big, long-term science project for some other species. Or we’re like The Truman Show, where the entire planet is entertainment for another species. LOL