Gravitational waves, what is it?

Gravitational waves, what is it?

Recently the research on cosmology has touched a level of difficulty that just a few people are able to understand. However, the cosmology is almost entirely based in the theory of general relativity. So the understanding of some points from that theory can allow us to understand a little of "classical cosmology". Current cosmology deals with multi-universes and other things like that, that is, effects that arises when are put together quantum mechanics and general relativity.

Gravitational waves are a immediate consequence of the general relativity. They are obtained even just in the classical cosmology, although its source are quantum effects. To understand what are gravitational waves we can make use of a basic analogy. Assume an electric charge and also that we are in a inertial system of coordinates in relation to the charge. Then if we are watching the charge moving, it's well known from the electromagnetism that we will to observe a electric field. Now, if we are in a accelerated motion in relation to the charge, also is well established that we will note a magnetic field as well. What we know as electromagnetic waves are just deformations on this field, called electromagnetic field.

In a complete analogy, the gravitational waves are just deformations on the gravitational field, which is our old friend since Galileo and Newton. But we need to use the general relativity to realize that. Nevertheless, we can not to measure signal of gravitational waves in a direct way yet. That happens due to the fact that the intensity of the gravitation interaction is much lower than other interactions, for instance, electromagnetic interaction. 

In the next post, I'll expose some devices which are candidates to measure directly signal of gravitational waves. Before, however, I must to show some sources from these waves.

Any question, it will be a pleasure to discuss about it.