Edit: Okay ... I give up. I wasted a lot of time googling for an original source or a video where Hawking actually said these things. My Google search skillz are off this early in the AM and I can't bear to see more ads associated with 1 minute clips. The story that humans should stop trying to contact aliens (attributed to Hawking) became quite popular a few years ago. I even recall someone from SETI saying how this is not what they are doing ... rather, they are merely listening for signals from intelligent life that may exist rather than attempting to initiate contact.
That's a HN submission with good comments, where he basically gives the plot of independence day.
I'm more worried about alien life forms due to the Great Filter problem, personally. Other life is bad news for our chances at a cosmic-proportion, galaxy-changing Singularity.
http://www.huffingtonpost.com/2010/04/25/stephen-hawking-ali...
Edit: Okay ... I give up. I wasted a lot of time googling for an original source or a video where Hawking actually said these things. My Google search skillz are off this early in the AM and I can't bear to see more ads associated with 1 minute clips. The story that humans should stop trying to contact aliens (attributed to Hawking) became quite popular a few years ago. I even recall someone from SETI saying how this is not what they are doing ... rather, they are merely listening for signals from intelligent life that may exist rather than attempting to initiate contact.