“”Yawn. There aren’t any extraterrestrial aliens visiting from another solar system for the same reason we can’t visit other solar systems. You can’t get there from here and they (if they exist) can’t get here from there. They’re too far away. Nearest star is something like 30 trillion miles away. The Saturn probe took 7 years to get to a planet one billion miles away. The nearest star is 30,000 times that far so 7 years times 30,000 = 210,000 year journey. And that’s just the closest star. We can look, but we can’t touch.””
***
Ever heard of wormholes?
Even if we don’t have the knowledge or technology... that does not mean that it is not possible.
Can you show me a wormhole aliens could use to transverse the Universe?
The first rule of the Dunning Kruger club is you don’t know you’re in the Dinning Kruger club, but you appear to be a member. It isn’t engineering tootsie roll it’s the fundamental physics. Let me know when you find a wormhole.
Wormholes are still strictly theoretical - a mathematical artifice. There is NO evidence of their existence!