  The era of high precision Cosmology has shown our ignorance about the
composition of the Universe. In this context, there has been a renewed interest
on Alternative Theories of Gravity. Through the experience of a graviton
measured by the LIGO collaboration, we shall understand the conceptual
framework of those theories. They provide us with a theoretical construction
where we can contrast the predictions of General Relativity and a possible
scenario to describe the accelerated expansion of our Universe without assuming
the existence of dark components. During the dawn of gravitational wave
astronomy, gravitation is already promising to be one of the most fascinating
fields of research of the XXI century.
