Only after seven Months, a huge team of scientists working with the instrument for dark energy spectroscopy has already mapped the universe larger than all other 3D surveys combined. And since they’re only 10 percent of the way through their five-year mission, there’s more to come.
DESI, pronounced like Desi Arnaz’s name, has revealed an astonishing cosmic network of more than 7.5 million galaxies, and will survey up to 40 million. The instrument was funded by the US Department of Energy and installed in the 4-meter Nicholas U Maywell Telescope at Kate Summit Observatory near Tucson, Arizona. It measures the exact distances of galaxies from Earth and their emitted light in a range of wavelengths, achieving both quantity and quality at the same time. It will eventually cover about 8000 square degrees, about 20 percent of the sky. The science gained from analyzing the data is yet to come, but it will especially help astrophysicists as they research how the universe is expanding.
“It really is a great adventure. We have been able to carry on despite the pandemic. We had to shut down for a few months and then adapt,” said Julian Gay, DESI project scientist at Lawrence Berkeley National Laboratory, the lead institution for the collaboration. Mostly; every morning scientists get data on up to 100,000 galaxies collected overnight, he says.
“It’s amazing how well this instrument works and how well designed the exit and distances into these galaxies are. Jason Rhodes, a research scientist at the Jet Propulsion Laboratory in Pasadena, who works on space telescopes to map galaxies in the early universe.
DESI actually consists of several instruments installed inside the telescope’s 14-story dome. The circular focal plane is placed near the top, and consists of 10 wedge-shaped petals, each containing 500 small robots. It’s what enables the instrument’s galaxy mapping: These 5,000-pencil robotic actuators position optical fibers that must be positioned precisely within 10 microns — less than the thickness of a human hair. This allows the tool to collect accurate data on 5,000 galaxies at once. Then the telescope points to another region of the night sky and begins work on the next five thousand. In contrast, in one of DESI’s predecessors, the Sloan Digital Sky Survey, based on a telescope in southern New Mexico, scientists had to manually drill holes in a circular aluminum plate at the telescope’s focus for each set of measurements, delivering a little power. fibers for every galaxy they wanted to observe.