This is SO important.
Actually, as there is no extraterrestrial life in our solar system, and other solar systems are too far away for any practicable travel, the questions is moot.
Don’t speak with such certainty about things like that. It sounds too much like the government officials who wanted to shut down the Patent Office after the Steam Engine was invented, since they thought everything that could be invented already was.
What we DON’T know about space travel is probably enormous compared to what we do know.
And the math for gravitational travel (instantaneous point to point) does exist. Wormholes are more than a theoretical construct.
We just don’t know how to make and control them yet
[But I am biased- I believe Bob Lazaar’s story about the gravitational drives on the alien spacecraft he worked on at Groom Lake (Area 51)]
If thy can sneak though our borders, they can surely sneak in from another galaxy!
It has always amazed me that, on a planet that is largely covered with oceans, we insist on believing that superior races must originate from distant planets.
“This is SO important. Actually, as there is no extraterrestrial life in our solar system, and other solar systems are too far away for any practicable travel, the questions is moot.”
I believe both of your statements will be found to be incorrect but it won’t happen any time soon. :-)