The NASA telescope discovers unusual galaxies as soon as the dawn of the universe

Astronomers who monitor the skies with NASA's Spitzer Space Telescope have been able to trace back to the first universe, 13 billion years ago, and discover some of the very first galaxies.

They look like tiny orange dots shining in a sea of ​​darkness – not so different the famous first image of a black hole – but the tiny lights imagined by Spitzer contain a host of young stars composed mainly of hydrogen and helium. The discovery of these galaxies of unexpected brightness could provide new clues to one of the most important cosmic events in history: "the era of reionization".

The new research, published in the Royal Astronomical Society's Monthly Opinion magazine in April, forced Spitzer to look at the same region of the sky for over 200 hours, studying the ancient cosmos as part of a campaign known as re-ionization product name Spitzer Extended Area Treasure (GREATS). Another excellent, the Hubble Space Telescope, also contributed to the data.

With so long formed on a region of the sky, Spitzer was able to gather the light that had crossed the universe to reach us. In what amounts to a cosmic gaze contest, Spitzer did not blink. The telescope detected weak infrared signals from 135 distant galaxies, produced by high levels of ionizing radiation.

This is a particularly important finding, as it is thought that ionizing radiation contributed to the era of reionization in the early universe – a cosmic transformation that shaped the world of the world. universe as we know it today. Astronomers are still perplexed about the exact cause of these changes, but the first galaxies detected by Spitzer can provide some clues.

"Our latest Spitzer result reveals how these early galaxies are different from those of future generations and identifies our sample as a key element to better understand how galaxies have reionized the universe so effectively," said Garth Illingworth, co-author of the new study.

The results were surprising for Michael Werner, Spitzer's project scientist at NASA's Jet Propulsion Laboratory.

"We did not expect Spitzer, with a mirror no larger than the size of a hula-hoop, to be able to see the galaxies so close to the dawn of time," he said. he said in a statement. "But nature is full of surprises and the unexpected brightness of these early galaxies, combined with Spitzer's superb performance, puts them within the reach of our small but powerful observatory."

Spitzer, launched in 2003, is an infrared observatory in Earth orbit operated by NASA and the California Institute of Technology. He carries three instruments that allow him to "see" through the wavelengths of infrared light, offering spectacular views of the distant gaseous and dusty cosmos.