Originally Posted by PR_Glen

a. if they can jump across galaxies within a lifetime? they have food figured out.

b. if they built ships or structures that can travel these distances they don't need slaves to build them or anything else either.

c. if they travel this far the ONLY possible thing they could need from us is water and even we have figured out how to prolong water use in space so the idea they would need to mine planets for water is just as unlikely.

hawking's new found paranoia has a hidden agenda. He is basically daring governments to build defenses for such things which will in essence force us to work on future technology development--or at least plant the seed. A virtual cold war against a practically non existent enemy.