What evidence supports the predicted existence of gravitational waves?

Question

1. What evidence supports the predicted existence of gravitational waves?

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


2.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?

A.Time runs slower on the surface of the Sun than on the earth.
B.Space is different for different observers. Time is different for different observers. Spacetime is the same for everyone.
C. Gravity is curvature of spacetime.
D.E = mc2
E.If you observe someone moving by you, you'll see their time running slow.


3. Which of the following is false?

A. Observers in different reference frames measure the same speed of light.
B.Nothing can move faster than the speed of light.
C.The absoluteness of the speed of light is an experimentally verified fact.
D.The speed of light slows down near a black hole.
E.The speed of light in a vacuum is constant.



4. Which of the following is false?


A.Time dilation is an observationally verified fact.
B. If one observer measures two events to be simultaneous, all observers must agree on their simultaneity.
C.From your point of view, time runs slower in the reference frame of anyone moving relative to you.
D. The order of events can be different for observers in different reference frames.
E. Time runs slower near a black hole.

Answer 1

1. c

2. d

3. d

4. b

Answer 2

Sounds like someone's homework or (even worst) take-home test.

Also, looks a lot like multiple-choice (frowned upon, you know).



There: I am frowning. { : - |



Now that the frowning is out of the way...



1. Gravitational waves have never been observed. However, someone had calculated how much energy they should carry IF THEY EXISTED. One day, astronomers observed a pair of very dense stars (one neutron star in orbit around another star) whose orbits was losing energy at exactly the rate that should have been carried away according to the calculation.



2. The energy from the Sun begins in the core, where hydrogen is fused into helium. It takes 4 hydrogen atoms to make one helium atom. However, the total mass of 4 hydrogen atoms is a tiny bit more than the mass of one helium atom. Therefore, a tiny bit of mass is lost each time. So many atoms are fused every second, that the Sun loses a mass equivalent to 4 million tonnes!

This mass is turned into energy, with the amount of energy coming out in accordance with Einstein's famous equation.



3. Actually, B and D are both false. However, B is a common misunderstanding of what the theory of Relativity says. Nothing with mass can move at the speed of light (it would have infinite energy). Nothing with mass can be accelerated beyond the speed of light (it would take even more energy than infinity -- if that makes sense). However, the theory does NOT forbid objects from existing if they already go faster than light. We have never observed any such object but that does not stop us from having a name for them: tachyons.

http://en.wikipedia.org/wiki/Tachyon



But I suspect that the teacher is looking for the other answer: We know that A, C and E are true. Therefore D cannot be true, since it contradicts at least one of them.



4. A was observed on Mount Washington in New England, USA.

B is false.

C. is true.

D. contradicts B (if D is true, B is false // if B is true, then D is false)

E. This is only true if you use the same definition as C. For an object falling towards the black hole, time is perceived as being the same, with the rest of the universe appearing to be slower.



Here, I suspect the answer they want is B. The reason is one of "exam logic". Just by reading the statements, we know that B and D are the opposite of each other. They cannot be both true. At least one must be false. Since I know D is true...

Answer 3

Einstein's paintings in particular and primary relativity confirmed that gravity is now not on the spot as Newtonian physics assumed. as a substitute, gravity is one thing like a wave, as you pronounced. The wave spreads out in the direction of infinity through the years, yet weakens because it travels farther from the resource. (clone of a bowling ball on an past mattress is in many instances used to reveal how gravity bends area, despite the fact that the assumption of ripples in a pond greater beneficial illustrate how gravity 'waves' improve.) consequently one thing 5000 easy years away may desire to certainly sense the gravitational pull of an merchandise it is now not even there anymore. despite the fact that, the thing may desire to may desire to be fairly massive (like a pair black holes placing out collectively) for the consequence to be considerable.