Sunday, January 31, 2016

Too hot for Interstellar?

OK, I still haven't seen Interstellar (I've read too much about it that puts me off, but I'll get around to it one day), but it seems that the whole physics set up (giant planet around a black hole "star") gets the details wrong, after all.  (Not sure what Kip Thorne, the physicist who came up with the movie scenario, thinks of this.)

From New Scientist:
Wondering if any more power might be available, the team turned to the film Interstellar, in which a world called Miller’s planet orbits very close to a massive, spinning black hole called Gargantua. General relativity means the black hole’s gravitational pull slows time on the planet so that 1 hour is equal to seven years off-world, a factor of around 60,000.
“We saw the movie, it was a very interesting idea, but then we started thinking about the problems,” says Opatrný.
The energy of light is proportional to its frequency. This means that when light from the CMB hits Miller’s planet, and its frequency is increased by this time dilation, its energy increases. With a time-dilation factor of around 60,000, Miller’s planet would be heated to nearly 900 ˚C.
In the film, the planet is swept by huge tidal waves of water, but Opatrný says his calculations mean molten aluminium would be more likely. Conditions would be cooler if the planet were slightly further out from the black hole, lessening the effects of time dilation and making it more hospitable to life. “It’s interesting that [the analysis] suggests the microwave background would be disastrous for observers on the planet, making the movie once again less realistic,” says Lawrence Krauss of Arizona State University.

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