Project makes a more accurate picture of cosmic evolution over the last 7 billion years – Sidereal Messenger

The Dark Energy Survey project presented the results of three of its six years of observation and provided the largest map of the spread of galaxies ever made. The work, the result of an international collaboration led by Fermilab in the USA, involving more than 400 scientists in seven countries (including Brazil), was carried out with the Dark Energy Camera installed at the Blanco telescope in Chile.

With 570 megapixels, it is one of the most powerful digital cameras in the world and was used between 2013 and 2019 for 30% of the time available on the Blanco, capturing around an eighth of the sky in 758 observation nights. – The galaxies presented correspond to the first three years of observation and capture 226 million galaxies covering the last 7 billion years of the universe.

The total of 29 papers have been published in the arXiV repository and help create a sharper scenario about the evolution of the universe, especially in its more recent times. It is estimated that the cosmos began with the Big Bang 13.8 billion years ago.

The project aims to help unravel the secrets of dark energy and dark matter. In either case, nobody knows what it is. But its effects can be demonstrated in astrophysical observations. Gravitational lenses, created by galaxies and clusters, make it possible, for example, to estimate the total amount of matter in these objects, including the so-called dark part, which is not visible but creates gravitational effects.

Likewise, observations of the brightness and redshift of light from distant objects allow us to estimate the distance and speed of distance from them, which helps differentiate the contribution of dark energy to the universe – something that scientists like dark matter don’t know what it is, but you see its effect in the form of a force that accelerates the expansion of the cosmos.

The results of the Dark Energy Survey are compatible with the so-called standard model of cosmology, which specifies a universe with the following recipe: 5% common matter, which is formed from atoms to form stars, 25% dark matter, from “cold” particles in quotation marks because they have low speed, 70% dark energy, and behave like the cosmological constant that Einstein introduced into his theory of relativity in 1917.

However, they reveal some fascinating discrepancies that are added to other observations related to the closest, i.e., younger, universe. For example, the Dark Energy Survey suggests that the matter in our environment is a little less crowded and concentrated than the model predicted. It is to be hoped that a full analysis of six years of observation will make it possible to identify these discrepancies even more precisely and possibly provide clues that lead to concrete progress in deciphering these mysterious “dark” components of the universe.

This column is published in Folha Corrida on Mondays.

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