About 14 billion years ago, our universe erupted with an extraordinary “spark” that started the Big Bang. In the first fleeting fraction of a second, the universe expanded exponentially, stretching far beyond what the best man-made telescopes can see. This accelerated expansion, known as cosmic inflation, was until now a simple theoretical formulation difficult to prove, among other reasons, due to the degree of uniformity that the visible universe presents. Now, a team of scientists led by the Harvard-Smithsonian Center for Astrophysics, has starred in a true milestone in cosmology. Through the BICEP2 telescope, installed at the South Pole, it has obtained the first images of gravitational waves, considered as the “Big Bang tremors” , which would corroborate the ultra-fast expansion of the universe and would validate the last assumption of the Theory of Relativity Einstein’s General.
Albert Einstein postulated in his Theory of Special Relativity that time is one more geometric dimension and not an independent coordinate of the observer. In his Theory of General Relativity, the genius of physics specified that gravity is not an isolated force, but rather is part of a single force that explains all known physical phenomena that has yet to be discovered. Space, understood as an essentially flat surface, is deformed by mass, thereby acquiring said additional physical dimension, which would be linked to the coordinates of width, length and depth. This space-time fabric is curved due to the presence of massive bodies as if it were the surface of a trampoline, which causes the effect of gravity and the orbit of objects around other objects. This premise contradicted Newton’s physical theories, which claimed that the Sun exerted an instantaneous attraction on the planets. In this sense, gravitational waves would be the disturbances generated in the fabric of the universe due to the changes experienced by the objects that deform it, similar to the waves on the surface of water when we throw a stone . These are caused by violent variations in the amount of energy (quantum fluctuations), such as those generated by the explosion of a supernova or the formation of a black hole. If the Sun disappeared, for example, we would not perceive a change in our orbit until these waves, which travel at the speed of light, reached our planet.
Alan Guth’s theory of inflation posited long after the expansion of the universe went through a brief phase of accelerated expansion, in which the first gravitational waves were generated. His main successor was the physicist Andrei Linde, who postulated the modern version of the theory. Inflation is currently considered to be part of the standard hot Big Bang cosmological model. The elemental particle responsible for this expansion is called inflaton, which underwent a phase change through which it released its potential energy in the form of matter and radiation, thus causing the expansion of the universe.
Einstein considered at the time that the trace of the original gravitational waves would be so faint that we would never be able to detect it. However, the group of scientists who created the discovery was surprised to detect a signal in the polarization of the background radiation much stronger than expected . Background radiation is a form of electromagnetic radiation that arose in the universe before the birth of the first stars. The subtle variations present in this type of light wave constitute the imprint of the quantum fluctuations produced after the initial explosion that originated the universe. These waves have an equivalent temperature less than 3 K, three degrees above absolute zero. To perform the measurements, a completely new technology was devised, a camera on a printed circuit board that includes an antenna to focus and filter polarized light. The team has analyzed the data for more than three years to rule out any errors, including the effect of dust from the Milky Way, which could leave a similar signal.
This work, which has not yet been published in any scientific journal but is already sensed as the next Nobel Prize in Physics, presents the first reliable evidence of the theory of cosmic inflation and is therefore of incalculable quantity on the way to the understanding the origin of the universe.
