Q. Could a human being who has a life expectancy of 70 years possibly make a round trip journey to a part of the universe thousands of light-years distant? Explain.
A. Yes, but only if the vehicle uesd is capable of reaching near light speeds. The closer one gets to moving at the speed of light, the slower the passage of time for that person.
Q. Exactly what is equivalent in the principle of equivalence?
A. Observations in an accelerated frame are equivalent to those made in a Newtonian gravitational field.
Q. Which runs faster, a clock at the top of the Sears tower in Chicago or a clock on the shore of lake Michigan.
A. A clock at the top of the Sears tower runs faster. The closer one gets to the centrifugal gravitational force of the Earth, the slower the passage of time, though the difference is only a few millionths of a second per decade.
Q. An astronatu awakes in her closed capsule, which actually sits on the moon. Can she tell whether her weight is the result of gravitation or accelerated motion? Explain.
A. She cannot tell since both appear equivalent to each other.
Q. An astronaut is provided "gravity" when the ship's engines are activated to accelerate the ship. This requires the use of fuel. Is there a way to accelerate and provide "gravity" without the sustained use of fuel?
A. Yes. A rotating spacehip can create the centrifugal force necessary to simulate gravity. Fuel will only be needed to start the rotation, it can then be turned off as its own momentum will keep it rotating perpetually in the frictionless vacuum.
Q. Why will the gravitational field intensity increase on the surface of a shrinking star?
A. It would increase as the gravitaional field strengthens from its closer proximity to the center.
Q. How can we "observe" a black hole if neither matter nor radiation can escape from it?
A. We can "observe" black holes by its gravitational effects on other objects.