Last night I saw the first part of Stephen Hawking’s Universe, about extraterrestrial life. Hawking’s views on this have been widely circulated:

• Don’t talk to aliens, warns Stephen Hawking

• Hawking: Beware the Alien Menace!

• How do you say “realpolitik” in Klingon?

• In which I disagree with Stephen Hawking

  Apparently Stephen Hawking read my book, but not very carefully, because he thinks aliens will come here ala ‘Independence Day’ and eat up all our resources and move on.

  I disagree with him. I think in fact it’s more likely that an aggressive alien race would create self-replicating robot probes that will disperse through the galaxy and destroy all life that way.

  Long-time SF readers will recognize the last concept.

A couple points:

1. I am not concerned about disclosing our existence to Extraterrestrials, for the simple reason that is way too late to worry about that. Any aliens within about 70 light years who can build a radio telescope will quickly find out we are here. That region, the Earth’s Radio Sphere, is filled with all our radio and television broadcast and radar scans. It is expanding in all directions by one light-year every year. There is absolutely nothing we can do about it.

2. The whole idea that extraterrestial would come to here mine our planet is absurd. The energy cost of lifting substantial amounts of anything out of Earth’s gravity well is prohibitive, as is well known to advocates of the colonization of space. If aliens have some enormous source of energy that would make this effort trivial they could use it to synthesize what ever they want, rather than looking for it and digging it out.

I am not rejecting Phil Plait’s suggestion that they might simply want to wipe us out. They could consider us as potential competition, or simply as vermin that should be exterminated.

Of course, they simply might not exist. I wrote an article about this some years ago. I am not so certain today, given the large number of exoplanets that have been discovered recently.