If aliens were to visit us it’s a miracle not only in space but also in time.
Space is huge, for some aliens to randomly arrive here would mean they are just about everywhere. We would surely see signs of them in other solar systems, even if they haven’t visited here. There are so many solar systems out there, you don’t just randomly stumble upon ours. And the space in between systems is also so big our brains literally can’t fathom it.
But time is huge as well. Humans as a civilization with electricity and technology has only existed for 200-300 years (being generous). Some say aliens have only been interested in us since the atom bomb, which is not even 100 years. However humans as a species has existed for over 100,000 years. And intelligent tool users have been around for about 1,000,000 years. If aliens visited anywhere in that time they would have laughed at the silly monkeys and have been on their way. For them to have randomly stumbled upon us just as we are enjoying our few hundred years of modern civilization is one hell of a coincidence.
Space is mind bogglingly huge, time as well, for both to line up perfectly for aliens to happen upon us is impossible. Even if life is abundant in our galaxy, the separation of time and space pretty much excludes any chance for contact.
That’s within a solar system, where distance, time lines and energy is relatively low.
Any event with enough energy for something to leave the solar system, destroys all life, even microscopic. And even if somehow it does survive and leave the solar system, space is pretty much empty so it will probably never hit anything. But if it does hit something, 99% of what’s out there is stars. So it would end up in a star. And if it does hit a planet, coming in at intergalactic speeds absolutely destroys any life. None of that matters though, because the distance involved is so freaking huge, nothing living can survive that long. Travel times are so long, only fossils would arrive, that’s how long we are talking.