Left out other telling features: our skeletons are meant for lower gravity; hence, flat feet, weak knees, and chronic backaches. Oh, and bunions! Can’t forget bunions; a fantastic clue to our other-world origins.
Good thing they came to a planet with compatible proteins, and that they had all those other hominids with them to confuse modern researchers regarding similarities of DNA.
Too bad, back in 1947, we killed the rescue mission that was sent to find & succor the survivors. No; we are not related to the Greys; they are artificial constructs—androids—used for routine ‘grunt work’.
Our ancestors didn’t have any with them; and being rich white conservative playboys, just had to muddle along as best they could, with the raw materials and at hand, having lost all advanced tech when their ship crashed...or the Intergalactic Prisons Commission kicked them out, naked and tooless.
Cosmos in Collision seems to start with the idea that our solar system was originally in two parts and the logic seems compelling:
http://en.wikipedia.org/wiki/Axial_tilt
If our solar system had arisen in any sort of an organized way, particularly if the planets had formed up from swirling masses of solar material as per the usual claim, you'd expect the axes of the planets to be roughly perpendicular to the plane of the system. The sun, Jupiter, and Mercury do in fact show that. Uranus and Venus are special cases of sorts, but Neptune, Saturn, Earth, and Mars with their roughly 26-degree axis tilts pretty much have to be an original system of some sort which was captured, by our sun, as a group. At least that's the simplest explanation for it.
There's also a question as to why anybody ever worshiped Jupiter and/or Saturn. Primitives looking for something in the sky to worship today would end up worshiping the sun and the moon, but the two chieftain gods of every one of those old religions were Jupiter and Saturn, and particularly Saturn. The main Roman religious festival was "Saturnalia" and our sabbath is still called "Saturn's Day".
Plato consistently referred to antediluvians as "Nurselings of Kronos (Saturn),and Hesiod and Ovid both refer to the pre-flood era as an age "when Saturn/Kronos was "King of Heaven". In the same language, our sun is the "King of Heaven" now.