Greying humans are real, and they typically come from different existences, an existence is a very, very long time, but in a dimension much higher than we can conceive, and it takes a really, long time to get there.
Greys do a variety of things around the galaxy, similar to "referee's", they are the starters of language, and they pick up the slack where humanity fails to support each other. Spending too much time touching the universe will effectively leave a residue on your spirit, effectively leaving trace amounts of energy into your spirit.
Anyway, we aren't firmirmenting our planet so they can grab the extra energy to keep their bodies and blood moving while they wait on their own planets and soul trains so they can get their humanity back.