NASA's Spitzer Space Telescope peeked into the ancient history of the universe by studying some of the first galaxies to appear after the Big Bang.

In a study, a team of researchers reported that some galaxies that formed in the early universe 13 billion years ago are brighter than expected. They believe that the new findings can offer clues to the Epoch of Reionization, the point when the universe turned into a bright starscape.

Far Back Into The History Of The Universe

The Spitzer Space Telescope looked at two regions of space for over 200 hours to collect light that have traveled across the universe for 13 billion years before it reached Earth. The researchers also used archival data from the Hubble Space Telescope. They published the study in the Monthly Notices of the Royal Astronomical Society.

The team observed 135 distant galaxies that are bright in wavelengths of infrared lights that are produced by ionizing radiation interacting with hydrogen and oxygen. This suggested that the distant galaxies were filled with massive stars that are mostly hydrogen and helium, and smaller amounts of heavy elements such as nitrogen, carbon, and oxygen.

These ancient stars are not the first to form in the universe, but they among the first generations.

"We did not expect that Spitzer, with a mirror no larger than a Hula-Hoop, would be capable of seeing galaxies so close to the dawn of time," commented Michael Werner, the project scientist behind Spitzer.

The Evolution Of The Universe

The study shows that galaxies with excessive brightness were more common in the early universe and offer clues as to what might have triggered the Epoch of Reionization.

"These results by Spitzer are certainly another step in solving the mystery of cosmic reionization," stated Pascal Oesch, an assistant professor at the University of Geneva. "We now know that the physical conditions in these early galaxies were very different than in typical galaxies today."

The researchers are waiting for the James Webb Space Telescope to continue studying the sky and investigate the Epoch of Reionization hundreds of millions of years after the Big Bang. The James Webb Space Telescope is scheduled to be launched in 2021.

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