After seven months of working with the Dark Energy Spectrometer (DESI) tool, a large team of scientists have been able to map a large part of the universe that is larger than previous three-dimensional maps. Since this research is at the beginning of its fifty-year path, better results will definitely be obtained.
DESI has mapped the spectacular cosmic grid, which includes more than 5.7 million galaxies, and that number could reach 40 million. The device, funded by the US Department of Energy, is mounted on the Nicholas U. Mayall 4-meter telescope at the Kate Peak National Observatory near Tuscany, Arizona, and is a collection of precise galaxy distances from Earth and light emitted in different wavelengths. Measures. The telescope covers 14,000 square degrees, which includes a third of the sky. The telescope data will help scientists study the expansion of the universe. “Julian Guy, a DESI project scientist at Berkeley Lawrence National Laboratory, says:
This research is a fascinating adventure that we were able to do despite the corona world. Of course, we had to stop working for a few months and resume work. Today, data processing and monitoring are automated. Every morning, scientists receive data from nearly 100,000 galaxies collected overnight.
“Jason Rhodes, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena and a researcher in mapping the galaxies of the early universe, says:
The performance of this tool and its good design for measuring the distance of galaxies is amazing. This device is incredibly good at capturing data, something that has been very difficult in the last two decades.
Sloan’s digital map of the sky (left) and dark energy (right) spectroscopy instrument record light emitted from the universe when it was halfway through the universe.
The DESI actually consists of several devices mounted inside the telescope’s 14-story dome. The circular focal plane is located near the top of the dome and consists of ten blades, each equipped with 500 small robots. These devices make galactic mapping possible: 5,000 pencil-sized robotic motors help locate optical fibers in areas of 10 microns less than a human hair. In this way, the instrument can collect accurate data from 5,000 galaxies together. In contrast, in pre-DESI instruments such as the Sloan digital sky map on a telescope in southern New Mexico, scientists have to manually make holes in the aluminum plate of the telescope in focus for each measurement and migrate fibers to observe each galaxy.
DESI spectrometers are located at the bottom of the telescope. These spectrometers break down the light of each galaxy into a full range of colors. This makes it possible to measure the “redshift” or redshift of the galaxy, which can be used to measure the distance of galaxies (as the universe expands, light emitted from distant objects tends to turn red due to longer wavelengths).
With the available data, Guy and his team can observe the grid-like, complex structures of galaxies that can be as far apart as 10 billion light-years. Was.
When you look at the clear night sky, you can see the full expanse of the Milky Way by scanning the entire sky. Similarly, DESI reveals galactic superstructures only by systematically mapping large numbers of galaxies over large areas of the night sky.
DESI 3D scan of the world. The Earth is at the bottom left and shows the angle of view of the constellations Virgo, Snake and Hercules at distances of more than 5 billion light-years. As the video progresses, a 20-degree angle of view moves toward the constellations of Gavran and the Northern Crown. Each colored dot represents a galaxy itself, made up of 100 billion to 1 trillion stars. Gravity also transforms galaxies into structures called cosmic lattices, which include dense clusters, strings, and empty spaces.
“This project has a specific scientific purpose: to accurately measure the rate of expansion of the universe,” adds Guy. He refers to dark energy; Something mysterious yet pervasive that makes up nearly 70% of the world and causes it to expand faster. Guy and his colleagues hope to discover the true nature of dark energy. Their map will also solve one of the emerging problems of astrophysics; Scientists arrive at different answers by measuring the velocity of the near world (the world at present age) and by measuring the rate of expansion of the primordial world (the infant universe). No one knows how to describe this difference; But if DESI shows how dark energy evolves, it will help solve this problem.
Guy and his team want to release the first DESI data in 2023. This vast body of data helps scientists study millions of galaxies, and new machine learning and statistical tools are being developed at the same time. Shirley Ho, a cosmologist at the Flatiron Institute in New York City and a former Sloan Digital Sky mapping researcher, says:
I’m curious about what AI or deep learning can do with so much data. With these technologies, we can make unexpected findings.
In the years to come, DESI will not be the only tool providing the Galaxy Atlas. Next year, the Vera Rubin Observatory will be funded by the National Science Foundation, built on the arid mountains of northern Chile. This telescope will classify billions of galaxies. Astrophysicists are preparing the European Space Agency’s Euclidean spacecraft, which will be launched in 2023.
The Nancy Grace Roman Space Telescope is also scheduled to be launched in 2027. Both telescopes are equipped with instruments for measuring the distance and spectrum of galaxies in the deepest parts of the universe. Rhodes says:
Both Euclid and Roman telescopes rely on DESI to study the universe. These telescopes will operate in an attractive way based on DESI data.
For Hu, DESI and other massive cosmic maps are a reminder of the smallness of humanity in the universe. He says:
The fact that we can see a large number of galaxies is a great achievement; But each of these galaxies has billions of stars, and each of these stars may have a system similar to ours. I believe this is a humble experience that shows how insignificant we are.