[pachyderm]

Would extraterrestrials want to exterminate us for the greater good of the Milky Way? Would they consider us cockroaches? Cockroaches left in charge of increasingly advanced and destructive technology?

http://news.discovery.com/space/save...ty-110818.html

[mgran]

Since we don't know anything about what kind of aliens we'd be dealing with, we don't know. If they're daleks, then yes... we're in trouble. If they're tribbles, not so much so. Though they'd get annoying very quickly.

All that for a ??

[Timgt5]

The earth will one day be demolished for an interstellar bypass...

Hitchhikers Guide the Galaxy.

[KinakuraiAnimeQueen]

I think the earth will be destroyed by our own stupidity, then exhibited by other aliens. XD

[manicminer]

George Carlin explains it the best. In one of his hilarious rants he goes on about people wanting to "save" everything and says the worst are those who want to "save the planet." He says, "the planet is not going anywhere, we are." "The planet's fine, we're the one's who are f*#ked." And he is so right. The earth will eventually decide that its had enough of us and change the climate or create some kind of disaster in which the planet no longer support human life. "The planet will shake us off like a bad case of fleas."
I doubt said aliens will have anything to do with the end of the human race.