somehow, if what he is saying that aliens are extradimensional beings, then that could be true.
1) first, if one has to travel even approaching the speed of light(weird as it may seem, but speed of light is our cosmic speed limit) to the closest star system Proxima centauri which is roughly 4light years, then it will take one nearly around 4years. yet, travelling close the speed of light limit is extremely hard. no technology known to mankind can ever do that. not even gravitational slingshot which will probably take 20,000 years. travelling at the speed of light is a fairly easy calculation, one just have to have energy thrust square of a distance by an exponential factor. but that is extremely hard to do for particles that has mass. because the more you approach the speed of light, the more you become heavier. even photons which has a zero mass took 8minutes to reach the Earth coming from the Sun.
2) hyperdimensional physics by superstring theory and M(membrane) theory suggest that the universe is made of of several multiverses, thus several dimension. most are only aware mostly of 3D(3dimansional universe), while some, esp astrophysicist, know that time, by the newtonian discipline, is the fourth dimension of the vector space. however, superstring and M-theory suggest that there could be more than 4. there could be up to 24dimensions. so if we live in a multidimensional universe, then there could also be an extradimensional particles, and perhaps extradiemensional beings as well.
