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The documentary featuring Stephen Hawking that I referred to in my previous post was broadcast on BBC2 earlier this week. I'm not sure what has happened to the idea of it being broadcast in two parts, it seems to have been just one documentary film that lasted 90 minutes. Hawking was only on screen for a total of about two minutes out of the 90 minutes. I suspect that the documentary will be uploaded to YouTube within the next few weeks.
For people who didn't see the documentary, this article gives some idea of its content:
article on documentary
I was expecting the documentary to include a sizeable chunk of doomsayer material putting forward the case for why we had to find a replacement for Earth in the next hundred years, but thankfully that sort of material was absent.
Hawking seems to think the most suitable planet for a new Earth would be a recently discovered planet called Proxima B which orbits the closest star to our Sun, Proxima Centauri, a red dwarf star that is 4.2 light years away. Virtually everybody else would pick Mars in our own solar system as being the best available candidate. It is not currently known whether Proxima B is habitable, but Wikipedia suspects that it isn't habitable:
"Proxima Centauri b orbits the star at a distance of roughly 0.05 AU (7,500,000 km; 4,600,000 mi) with an orbital period of approximately 11.2 Earth days, and has an estimated mass of at least 1.3 times that of the Earth. Its habitability has not been established, though it is unlikely to be habitable since the planet is subject to stellar wind pressures of more than 2,000 times those experienced by Earth from the solar wind."
One thing that I expected in this documentary, given that a left wing, CND supporting scientist like Hawking was lending his name to the documentary, is that it would only promote politically correct forms of rocket technology, and it did. It only talked about plasma rockets, and talked up some light propulsion technology where tiny spacecraft (the size of a SIM card) are propelled by an array of laser beams to about one fifth the speed of light in order to do a reconnaissance mission of the Proxima B planet. Back in "The Space Age" (the 1960s and 1970s), it was regarded as a 'no-brainer' that the next generation of rockets would be nuclear powered, but the powerful Green lobby that emerged in the 1970s effectively killed that development off. Nuclear powered rockets were talked about as recently as ten years ago in connection with Bush's ill-fated moonbase project (the moonbase project was subsequently killed off by Obama) as mentioned in this Register article from 2007: