Mario Hamuy: trip (round trip) to the Big Bang

Marcela Rubina
Chilean Astronomy Foundation

The Universe is 13.8 billion years old, since the expansion began. We do not know exactly how it starts: if it started from what is called a singularity (that is, from nothing, if the whole appears from nothing) or, there was a stage prior to the expansion. What we do know is that the Universe began to expand. Initially, space has a huge amount of energy that makes it a very fast expansion; we are talking about the first fraction, of much less than a second, in which there is a brief inflationary stage and, after that, the remaining energy decants into fundamental particles. From all this soup of particles and energy, the Universe continues to expand, it cools down, the particles move away from each other and during the first ten minutes some chemical elements are formed (75% hydrogen, 25% helium), while the Universe keeps expanding, and then it slows down. At 400 thousand years, the Universe forms the first neutral atoms (hydrogen and helium meet electrons and form neutral atoms), at this date, stars did not yet exist, galaxies did not exist. After a few million years, the first stars begin to form and, from these first stars, clusters of stars are formed, which are galaxies. Some of these stars explode, in what is called a supernova, and these stars release new chemical elements from their entrails, which did not exist until then, which these stars had manufactured during their lives: carbon, oxygen, nitrogen, etc., and This new chemical material, more complex than hydrogen and helium, goes on to form a second generation of stars, and it is at this time that planets like Earth are formed. So, the atoms that make up the air, the oxygen, the nitrogen, come from inside a star; the iron, the calcium of the bones, are also star particles.

Apparently, matters as complex as the Big Bang and the expansion of the Universe are those that the astronomer and National Prize for Exact Sciences, Mario Hamuy, travels in his latest book “Journey to the Big Bang”. This is his third book, after “The Expanding Universe”, “Black Sun” and now he gives us this text that can be considered a great journey, moreover, through the life and work of this intellectual, whose passion for knowledge led him to be one of the protagonists of one of the most important events of recent times: the discovery of the accelerated expansion of the Universe.

Mario Hamuy had the idea of ​​being able to generate the “Calan Tololo” project, which was developed between 1989 and 1994, and which intended to measure the slowdown of the universe through its measurement from here some 500 million light years away. To the work carried out by that team, the arrival of two other teams was added who took these data and continued the investigation towards more distant supernovae. In 1998, as a result of this research, what is discovered is that the Universe is not slowing down, but is accelerating: that means that there is a force that we do not know that is equivalent to more or less 70% of the Universe. That investigation of the year 1998 gets to obtain the Nobel Prize in Physics and Mario Hamuy was a fundamental part of that process.

Beyond the satisfaction he feels at having paved the way for such a revolutionary discovery, Mario acknowledges that he came to supernova research by chance. He was 26 years old and had been hired to work at Cerro Tololo as a research assistant, a place he was to enter on February 27, 1987. It was by chance that two days before his arrival, a supernova exploded, the brightest in four centuries, a very close supernova in the Large Magellanic Cloud that could be seen with the naked eye, without the aid of a telescope. This event changed the course of Mario’s work, he was supposed to get to work on the largest telescope supporting the Director in an observation shift to learn from the most advanced technology in astronomical observation, but he ends up dedicated to observing that supernova. From there he organizes the “Calan Tololo” working group whose purpose was to discover supernovae in the southern hemisphere and see if they could be used as precise distance indicators. All this process led to a discovery that changed the history of astronomy.

Before getting to write the beautiful book that we are commenting on, and that leads us through a playful and poetic prose, through the limits of research and knowledge, our author has made his own interstellar journey during his own life: doctor in astronomy , tireless disseminator, inspired by a type of collaborative science, director of Conycit and who creates the foundations of the current science ministry, founder of the Chilean Astronomy Foundation, mentor and promoter of a large number of valuable scientists who see in the democratization of knowledge a lifestyle.

French philosopher Gaston Bachelard said “We all have a nucleus of childhood that we cannot lose” It is that precise place from which Mario tells us about the history of the Universe, which is his own history, a history that began with the wonder and contemplation of the sky of the child Hamuy, the same night that man reached the Moon.

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Mario Hamuy: trip (round trip) to the Big Bang