Question

Why can emission of gravitational waves lead to mergers of white dwarfs, neutron stars, and black holes?

A) Binary systems of compact objects experience the rapid pulsations of the radiation, known as pulsars. The variability of the light corresponds to the emission of the gravitational waves. The merging corresponds to the rapid decreasing of the radius, i.e. the merger of the compact object.

B) Compact objects have very large densities. When the compact objects are very close, the matter falls from one object to the other, emitting the gravitational waves if the matter is dense enough. Therefore, the gravitational waves are indicators of the matter accreting from one compact object to the other.

C) Compact objects are sustained from the gravitational collapse due to degeneracy pressure. As the gravity slowly contracts the compact object, leading to merging, and overcome degeneracy pressure, such objects emit gravitational waves.

D) Binary system of two compact objects emits gravitational waves, which carry momentum away from the system. As momentum is carried away, the orbital distance in the system decreases, leading to the collision of the objects.

Answer 1

Binary pairs create unique pattern of gravatational waves by a mechanism called inspiral. This occurs over a million of years as pairs of dense compact objects revolve around each other. In this process they release gravatational waves that carry some of it's oribital energy. Due to this over time they move closer and closer.

By moving close they orbit fast each other and releasing strong gravatational waves by losing more orbit 's energy and again move closer.

The pair of neutron stars or white dwarfs cannot halt the rotation and the process of emitting gravatational waves and orbiting closer and closer set of an unstoppable reaction that can only end with collision of two objects.

So answer is D.