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Black Holes Encyclopedia
FAQ

Doctor Who 'Impossible Planet' (2006)

TV Show

Doctor Who, 'Impossible Planet'

The Doctor’s time machine, the TARDIS, materializes on a planet that is orbiting near the inner edge of an accretion disk around a stellar-mass black hole. A team of researchers is studying the planet, which produces an odd gravity field that keeps it intact against the tidal effects of the black hole’s gravity. Anything that leaves the confines of the research station, though, is slowly pulled off the planet’s surface and into the black hole.

The Science

A planet or any other object with a strong gravitational field orbiting inside a black hole’s accretion disk would not last for long. The combined gravity of the object and the black hole would cause them to whirl around each other faster and faster, spiraling inward as they did so. The stress would easily destroy a rocky body like a planet, leaving only a pile of rubble to heat up and vaporize before it fell into the black hole.

And any planet close enough for the black hole’s gravity to pull objects off of its surface would itself be ripped apart in a hurry. Staying inside a research base would afford no protection at all.

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