### Which of the following statements about gravitational waves are true?

• a) The emission of gravitational waves from merging black holes is predicted by Einstein's general theory of relativity.

b) The first direct detection of gravitational waves, announced in 2016, came from the LIGO observatory.

c) Two orbiting neutron stars or black holes will gradually spiral toward each other as a result of energy being carried away by gravitational waves.

d) The emission of gravitational waves from merging black holes is predicted by Newton's universal law of gravitation.

e) Although gravitational waves are an important theoretical prediction, we do not yet have any observational evidence that they exist.

f) Scientists seek to detect gravitational waves by using powerful gamma-ray telescopes.

I personally think e is false because LIGO detected the gravitational wave already. For others, I think they are alright. But I am not sure if I missed anything. Could someone give any suggestion?

Is this a “homework problem”?

Before you post questions like this, you should see what information you can find on your own. Pretty much all you need to know to answer this question can be found on the Wikipedia page for gravitational waves.

I'm voting to close this question as off-topic because it is someone's homework.

• a) This is true. Gravitational waves have been predicted by General Relativity since 1916.

b) This is true. In February 2016, LIGO announced that they had detected gravitational waves resulting from a merger of two black holes.

c) This is true. Two objects orbiting around each other will slowly lose energy due to the production of gravitational waves, causing them to fall inwards towards each other.

d) This is false. Newton's laws assume that all interactions happen instantaneously. Gravitational waves and signals from gravity travel at the speed of light.

e) This is false because (b) is true.

f) This is false. There are two different ways to detect gravitational waves. The first is by using an interferometer, like LIGO, the Laser Interferometer Gravitational-Wave Observatory. By using a very large interferometer, scientists can detect minute changes in the length of the arms, due to the passage of a gravitational wave. The second way is by using a Weber bar, a large, solid antenna sensitive to changes in strain due to its resonant frequency. This second method has not yielded any results yet.