Assuming Einstein was correct, interspace travel isn’t possible even at the speed of light due to the distance.
The Universe is believed to be riddled with wormholes like a piece of swiss cheese. Who can say what highly advanced civilization has perfected the means of passing through them and has mapped them out like a subway system. Carl Sagan used this scenario for his novel, Contact.
“Assuming Einstein was correct, interspace travel isn’t possible even at the speed of light due to the distance”
Correct. As the famed physicist Enrico Fermi once noted, if interstellar travel was a reality, “Where is everybody?” Carl Sagan made the same astute observation.
One very interesting book on the subject is The Paranormal Conspiracy: The Truth about Ghosts, Aliens and Mysterious Beings.
As the book points out, if Earth was indeed being visited by extraterrestrial beings, why do they typically appear as fleeting objects high in the sky - often at night? As Sagan pointed out, why do these supposedly unimaginably intelligent beings fail to land on the White House lawn, or in a packed football stadium, or take over the TV airwaves to announce themselves? Something else is going on. Read the book.