30 million galaxies: work on the most precise 3D map of the cosmos has begun

In the USA, work has begun to measure the universe in a quality that has never been achieved before. Within five years, the Dark Energy Spectroscopic Instrument (DESI) at the Kitt Peak National Observatory in Arizona will now analyze the light of 30 million galaxies and use it to create the most precise 3D map of the cosmos to date. Among other things, those responsible want to track down the mysterious dark energy that is held responsible for the accelerated expansion of the universe. For this purpose, the 3D map should extend over the universe close to us to galaxies in 11 billion light years.

After Edwin Hubble and others showed that the universe was expanding at the beginning of the 20th century, research had long assumed that this expansion would slow down. It was not until 1998 that it was discovered through the analysis of distant supernovae that, on the contrary, the expansion is actually accelerating. For this, the US scientists Saul Perlmutter, Brian Schmidt and Adam Riess received the 2011 Nobel Prize in Physics. Since then, it has been assumed in physics that so-called dark energy is responsible for this acceleration. Their nature is still a mystery. The DESI experiment should now literally shed light on the darkness.

As those responsible now explain, they do not rely on the largest telescopes in their work, but on better instruments and more powerful software. Your instrument is installed at Kitt Peak National Observatory, southwest of Tucson, Arizona. Thanks to robot-controlled glass fibers, it can simultaneously capture the spectra of 5000 galaxies and thus measure up to 150,000 objects on a good night, explain those responsible. From the spectra, researchers can then not only infer the chemical composition of the radiating objects, but also their relative distance and their own movement. From this you can put together the most extensive map of the expanding universe in the end.

A small but particularly dense section of the sky …
(Bild: DESI collaboration and DESI Legacy Imaging Surveys)

DESI started its central task on May 17th, but before that it had already collected a lot of data in test runs. These were already the basis for other research, such as the search for so-called gravitational lenses. Most recently, the Dark Energy Spectroscopic Instrument had proven its operational readiness with the so-called one percent survey, in which one percent of the planned sky area was analyzed under the conditions of use. This alone has made the instrument the world’s second largest collector of data on the redshift of celestial bodies, i.e. the measure of their movement away from us Paul Martini from DESI explains.

Explanatory film about DESI

Explanatory film about DESI

(Quelle: Berkeley Lab)


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