How do they get here?

Can anyone explain, using known laws of physics, how aliens get here? Wormholes would require insane amounts of energy. Faster than light travel is not possible. Multidimensional travel has yet to be explained, even theoretically. So, how do they get here? I don’t mean this in a cynical or disrespectful way. I’m genuinely skeptical because no one has yet to be able to explain how they would get here.