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November 2, 2019
Involving researchers from EPFL, a project to unravel the nature of dark energy is entering its final phase of testing.
Image above: The Dark Energy Spectroscopic Instrument (DESI) is a project led by the United States to measure the accelerated expansion of the Universe to discover the nature of dark energy. This project, to which EPFL astrophysicists have contributed significantly, is entering its last phase of testing to map the sky.
The Dark Energy Spectroscopic Instrument (DESI) is a project led by the United States to discover the nature of dark energy. This project, to which EPFL astrophysicists have contributed, is entering its last phase of testing. The first results are expected in 2021.
Dozens of millions of galaxies
The DESI was developed to examine the nature of dark energy by measuring in detail the accelerated expansion of the Universe, said Wednesday the Swiss Federal Institute of Technology Lausanne (EPFL) in a statement. Dark energy is a mysterious element that constitutes about 68% of the mass-energy of the current Universe.
DESI has announced its "first light", entering its final testing and commissioning phase on the Mayall telescope at the Kitt Peak Observatory. This means that the instrument will be ready to begin its scientific observations in early 2020. The first major publication of data is expected by 2021.
Over the next four years, optical spectra of tens of millions of galaxies and quasars will be collected to create a 3D map covering the Near Universe up to 11 billion light-years.
To do this, DESI will use 5000 "eyes" of optical fiber to capture the light of 5000 different objects, mainly galaxies, but also quasars and some stars that will be used mainly to calibrate the instrument.
Distance to the Earth
DESI is designed to automatically point a predetermined series of galaxies, collect their light, and then, thanks to ten spectrographs, separate this light into narrow color bands to represent on a map their distance from the Earth. Scientists will be able to calculate the expansion of the Universe according to the light of the galaxies that has reached our planet.
The Making of the Largest 3D Map of the Universe
Video above: DESI, the Dark Energy Spectroscopic Instrument, will mobilize 5,000 swiveling robots - each one pointing to a thin strand of fiber-optic cable - to gather the light from about 35 million galaxies. The little robots are designed to make a series of preselected sky objects that are as distant as 12 billion light-years away.
EPFL scientists have, among other things, helped to determine which galaxies will be observed and to create the robotics system for positioning optical fibers.
The latter was carried out within the framework of the interdisciplinary group Astrobots, which will also participate in the processing of the huge amount of data that DESI will provide. EPFL and the Swiss National Science Foundation contributed nearly one million francs to the project.
Related links:
Dark Energy Spectroscopic Instrument (DESI): https://www.desi.lbl.gov/
Astrobots: https://astrobots.epfl.ch/
Laboratoire d’astrophysique (LASTRO): https://lastro.epfl.ch/
EPFL: https://actu.epfl.ch/
Image, Video, Text, Credits: ATS/EPFL/Berkeley Lab/Orbiter.ch Aerospace/Roland Berga.
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