A new study confirms that the light from outside our galaxy is brighter than expected

The scientists analyzed new measurements showing that the light emitted by stars outside our galaxy is two to three times brighter than the light from known populations of galaxies, challenging assumptions about the number and environment of stars. In the universe. Results of the study, led by researchers at the Rochester Institute of Technology, were published in arXiv and accepted for publication in The Astrophysical Journal.

The research team analyzed hundreds of backlight images taken by the Long Range Reconnaissance Camera (LORRI) on NASA’s New Horizons mission to calculate the cosmic optical background (COB), the sum of light emitted by stars beyond the Milky Way throughout history. of the universe. If the brightness of the COB is not equal to the light from galaxies we know of, it suggests that optical light sources might be lacking in the universe.

“We see more light than we should see based on the galaxy populations we understand exist and the amount of light we estimate they should produce,” said Teresa Symons Ph.D. (astrophysics science and technology), who led the study for her dissertation and is now a postdoctoral researcher at the University of California Irvine. “Determining what is producing that light could change our fundamental understanding of how the universe formed over time.”

Earlier this year, an independent team of scientists reported that COB was twice as large as originally believed. Astrophysical Journal Letters. Those results were no fluke, as corroborated using a much larger set of LORRI observations in the new study by Symons, RIT Associate Professor Michael Zemcov, and researchers at the Jet Propulsion Laboratory at Caltech, UC Irvine, UC Berkeley and Johns Hopkins University.

While it is difficult to achieve a clear measurement of the COB from Earth due to the dust between the planets, the New Horizons spacecraft is at the edge of our solar system where this foreground is minimal and provides a much clearer view for this type of study. Scientists hope that future missions and instruments can be developed to help explore the discrepancy.

“This has gotten to the point where it’s a real mystery that needs to be solved,” said Zemcov, a research professor in the Detector Center and RIT’s School of Physics and Astronomy. “I hope that some of the experiments we are involved in here at RIT, including CIBER-2 and SPHEREx, can help us resolve the discrepancy.”