The light-year is defined to be the
A) time it takes light to travel from the Sun to the Earth
B) time it takes for light to travel from the nearest star to the Earth
C) distance light travels in one year in space
D) average distance between the Earth and the nearest star
Question 2
At last, someplace fairly comfortable. Very weak gravity is holding you to the surface of the small object on which you sit. Your object is apparently moving away from a star, perhaps one that it orbits with a period of thousands of years.
Around you, geysers are spouting gas into space. Looking back along the object's orbit, you see particles of dust that the geysers apparently blew off the object when it was nearer to the star that it is now leaving behind. You conclude that the geysers were recently much more active but are now settling down into a quiescent state that may last for millennia. You also soon realize that you are closer to home than you have been in all your previous journeys. Perhaps if you can somehow find a small rocket, a heat shield, and a good parachute, you can escape and head home for your final exam. Where are you? A) You are on an asteroid near the center of a galaxy, heading in toward a massive black hole.
B) You have been shrunk in size and are riding a grain of interstellar dust that is carrying you on an orbit about our very own Sun.
C) You are riding a jet of gas from a quasar that is headed in the direction of an ordinary star.
D) You are on comet Hale-Bopp, circa May 1997.
E) You are at Disneyland on the Moon, riding the new wild and wet roller coaster.
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