The figure shows a cluster of stars like the ones analysed in this work. The emitted light loses energy as it escapes the gravitational field of each star. This energy loss manifests itself as a reddening that is larger for main-sequence stars with relatively small radii (right) than for giant-phase stars with larger radii (left). Credit: Gabriel Pérez Díaz (IAC). Background image: ESA/Hubble and NASA. Magnifiers based in an illustration by freepic.es.
According to Einstein’s theory of general relativity gravity affects light as well as matter. One consequence of this theory, based on the Principle of Equivalence, is that the light which escapes from a region with a strong gravitational field loses energy on its way, so that it becomes redder, a phenomenon known as the gravitational redshift. Quantifying this gives a fundamental test of Einstein’s theory of gravitation. Until now this test had been performed only on bodies in the nearby universe, but thanks to the use of a new experimental procedure scientists at the Instituto de
We perform a new test of Einstein's Equivalence Principle which, for the first time, extends to very early cosmological epochs (we have studied its validity in 80% of the history of the Universe). The Einstein Equivalence Principle is essential for generalizing physical laws in the presence of gravity. Our test of the Equivalence Principle is based on one of Einstein's classical predictions: the gravitational redshift of photons. This test has been accurately put into practice in our Solar System and in some stars in our Galaxy (e.g. Sirius B). However, so far it has not been applied to
Un equipo internacional, en el que ha participado el IAC, ha descubierto que las enanas blancas del sistema binario J0651 orbitan cada vez más rápido, tal y como predice la teoría de la relatividad general de Einstein, al perder energía por emitir ondas gravitacionales.
