Author Question: Over time, as they age, the habitable zone of stars like our Sun A) move inward B) remain the ... (Read 154 times)

ARLKQ · **on:** Jul 27, 2018

Over time, as they age, the habitable zone of stars like our Sun

A) move inward
B) remain the same
C) suddenly disappear
D) move outward

Question 2

Which of the following best explains the hypothesized phenomenon of black hole evaporation?

A) Particles (or anti-particles) are occasionally ejected from within the event horizon, causing the black hole to lose mass.
B) Virtual particles created near the black hole are constantly annihilating each other, causing a very high temperature even if the black hole has no accretion disk. This high temperature provides escape velocity for the virtual particles, causing the entire cloud of virtual particles to expand away into space.
C) Particles (or anti-particles) are created by a quantum mechanical effect near, but outside, the event horizon of the black hole. The law of conservation of energy maintains that the black hole must lose energy to pay for the creation of this mass.
D) Black hole evaporation is a virtual process, meaning that it has been theorized by astrophysicists, but doesn't really occur.