ASTR 1401 Chapter 8 – Flashcards

What do we mean by the straightest possible path between two points on the earth's surface? a path that crosses the equator a path that follows a circle of longitude the shortest path between the two points a path that follows a circle of latitude a path that actually is a perfectly straight line

Which of the following statements is not a prediction of the general theory of relativity? Different observers can disagree about the fundamental structure of spacetime. Time runs slightly slower on the surface of the Sun than on the surface of the earth. The Universe has no boundaries and no center. A binary star system with two stars orbiting each other rapidly emits gravitational waves. The curvature of spacetime can distort the appearance of distant objects.

Jackie is floating freely in her spacecraft, and you are accelerating away from her with an acceleration of 1g. How will you feel in your spacecraft? You will feel weight, but less than on Earth. You will feel the same weight as you do on Earth. You will feel weight, but more than on Earth. You will be floating weightlessly. You will feel yourself pressed against the back of your spaceship with great force, making it difficult to move.

Imagine that you are sitting in a closed room (no windows, no doors) when, magically, it is lifted from the earth and sent accelerating through space with an acceleration of 1g (9.8 m/s2). According to Einstein's equivalence principle, which of the following is true? You won't feel any change and will have no way to know that you've left the earth. You'll feel a force that will cause your head to repeatedly bang into the ceiling. You'll know that you left the earth because you'll be floating weightlessly in your room. You'll know that you left the earth because when you drop a ball it will fall sideways.

What do we mean by dimension in the context of relativity? the number of sides that we can see when we look at an object the height of an object the number of independent directions in which movement is possible the size of an object the letter used to represent length mathematically

If you draw a spacetime diagram, the worldline of an object that is traveling by you at constant speed is vertical. a circle. curved. slanted. horizontal.

If you draw a spacetime diagram, the worldline of an object that is accelerating away from you is a circle. vertical. slanted. curved. horizontal.

Which of the following correctly describes the conditions under which you will feel weightless, according to general relativity? any time you are traveling through space at constant speed any time your worldline is perfectly straight any time your worldline is following the straightest possible path through spacetime any time you are very far from any planet You can never be truly weightless.

Suppose two lines appear to be parallel but eventually meet. What type of geometry are you dealing with? flat geometry spherical geometry saddle-shaped geometry Euclidean geometry This situation can never occur.

According to general relativity, a black hole is a place where light travels faster than the normal speed of light. a place where light travels slower than the normal speed of light. a place where there is no gravity. an object that cannot be seen. a hole in the observable universe.

According to general relativity, how is time affected by gravity? Time runs faster in stronger gravitational fields. Time is not affected by gravity. Time is stopped by any gravitational field. Time runs slower in stronger gravitational fields. Time is affected by gravity, but not in a predictable way.

What evidence supports the predicted existence of gravitational waves? Gravitational waves have been detected by observing their effect on large masses suspended on the earth. The energy generated by gravitational waves from the Sun can be seen as it is absorbed by Jupiter. The orbit of a star system consisting of two neutron stars is slowly decaying, suggesting that energy is being carried away by gravitational waves. Gravitational waves are frequently and easily detected by large telescopes. Photographs of spacetime show the gravitational waves as ripples that are clearly visible.

Each of the following is a prediction of the theory of relativity. Which one is crucial to understanding how the Sun provides light and heat to the earth? Time runs slower on the surface of the Sun than on the earth. Space is different for different observers. Time is different for different observers. Spacetime is the same for everyone. Gravity is curvature of spacetime. E = mc2 If you observe someone moving by you, you'll see their time running slow.

Which of the following is false? Observers in different reference frames measure the same speed of light. Nothing can move faster than the speed of light. The absoluteness of the speed of light is an experimentally verified fact. The speed of light slows down near a black hole. The speed of light in a vacuum is constant.

Which of the following is false? Time dilation is an observation-ally verified fact. If one observer measures two events to be simultaneous, all observers must agree on their simultaneity. From your point of view, time runs slower in the reference frame of anyone moving relative to you. The order of events can be different for observers in different reference frames. Time runs slower near a black hole.