2021-05-23 14:11:40
Beyond the stars that spread across the sky at night for the inhabitants of Earth, beyond the galaxy that houses the Sun and hundreds of billions of other stars, the Cosmos houses an infinity of galaxies. The vision that we have of these distant and immense agglomerations of stars gives us a strange sensation because, as we move away from our small and battered world, we embark, at the same time, on a trip back in time. The finite speed of radiation, including visible light, means that the further away we focus our gaze, the younger the Universe around us, or rather, the younger the image we receive of it.
Today we are talking about extragalactic astronomy, that is to say, that part of astronomy that focuses its gaze beyond the Milky Way, towards a universe populated by galaxies that is increasingly distant and young. At these scales, the Universe not only teaches us the extreme smallness of the human being, but also shows behaviors that humans, despite all the science that we have managed to develop, cannot understand. The laws of nature, which we are so proud to show here on Earth, tell us that there is matter that we are unable to detect and energy that we are unable to see. A lack of knowledge that forces us to name them as dark matter and energy. Dark matter amounts to 80% of the matter in the Universe and, currently, 70% of the energy content of the Universe is made up of dark energy. These are figures that reflect the degree of our ignorance.
Today we present on the program an international effort to obtain a three-dimensional map of the Universe with which scientists hope to obtain data that will allow a better understanding of dark energy, which causes the acceleration of the expansion of the universe. The project consists of using the 4-meter Nicholas U. Mayall telescope of the Kitt Peak National Observatory (Tucson, Arizona, United States) coupled to a novel device called the “Dark Energy Spectroscopic Instrument (DESI)”. Our guest in Speaking with Scientists, Francisco Javier Castander, a researcher at the Institute of Space Sciences (Instituto de Ciencias del Espacio) participates in the project.ICE, CSIC) and the Institute of Spatial Studies of Catalonia.
DESI It consists of 5,000 robotically controlled optical fibers that make it possible to collect simultaneous images of as many galaxies and obtain their spectroscopic data. Once the test period is over, which during four months has allowed us to obtain data from 4 million galaxies, a period of five years now begins during which the scientists plan to collect the light record from some 30 million galaxies located at different distances. The data obtained will allow drawing a 3D image of the universe up to a distance of 11,000 million light years. As the data is collected, scientists will be obtaining images of the Universe at different moments in its evolution. The data obtained, when compared, will make it possible to discover how the energy content evolves as the universe ages.
I invite you to listen to Francisco Javier Castander, a researcher at the Institute of Space Sciences (ICE, CSIC) and the Spatial Studies Institute of Catalonia.
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