500
One of Mars’ moons, Phobos' revolution around Mars has shorten a few hundredths of a second every year. If this trend continues what will most probably happen to Phobos?
A. Phobos will eventually increase its rotation about its own axis, causing the moon to break apart.
B. Phobos is getting closer to Mars and will eventually fall to the surface of Mars.
C. the speed of orbit is decreasing and Phobos will eventually fly out of orbit from Mars.
D. Phobos will eventually increase its rotation, fly out of orbit from Mars, and crash into the Sun.
B. Phobos is getting closer to Mars and will eventually fall to the surface of Mars.