An advanced civilization lives on a planet orbiting a close binary star system that consists of a 15MSᵤn red giant and a 10MSᵤn black hole.Assume that the two stars are quite close together,so that an accretion disk surrounds the black hole.The planet on which the civilization lives orbits the binary star at a distance of 10 AU.
-Sometime within the next million years or so,their planet is likely to be doomed because
A)jets of material shot out of the accretion disk will shoot down their planet.
B)their planet receives most of its energy from the red giant.However,this star will soon be completely devoured in the accretion disk and thus will no longer exist.
C)the red giant will probably undergo a supernova explosion within the next million years.
D)tidal forces from the black hole will rip the planet apart.
E)the planet's orbit gradually will decay as it is sucked in by the black hole.

Question

Quizplus · Accepted Answer

The red giant is expected to undergo a supernova explosion within the next million years, which will result in the release of an enormous amount of energy capable of destroying the nearby planet. The other options are not likely to happen in the given timescale. The jets from the accretion disk are not directed towards the planet, and even if they were, they are unlikely to reach it from such a distance. The red giant's total consumption in the accretion disk would not cause the planet to be destroyed. Tidal forces could be a problem, but they are not mentioned in the question, and the planet is not close enough to be affected by the black hole. Finally, the planet's orbit is not expected to change significantly during the timescale mentioned in the question.

An Advanced Civilization Lives on a Planet Orbiting a Close