April 11 (UPI) -- Scientists have struggled to define the upper limit of the cosmic optical background, the total amount of light produced by all of the galaxies in the universe. But new observations from NASA's New Horizons spacecraft have allowed astronomers to place a ceiling on the measurement.
"Determining how much light comes from all the galaxies beyond our own Milky Way galaxy has been a stubborn challenge in observational astrophysics," Michael Zemcov, an assistant professor of astrophysics at the Rochester Institute of Technology, said in a news release.
The reflection of the sunlight off interplanetary space dust makes the task of measuring the cosmic optical background from Earth quite difficult.
The latest observations by New Horizons' Long Range Reconnaissance Imager, or LORRI instrument, suggests the outer regions of the solar system allow for more accurate measurements. Researchers detailed the findings in the journal Nature Communications.
"The study is proof that this kind of measurement is possible from the outer solar system, and that LORRI is capable of doing it," Zemcov said.
Spacecrafts traveling to the outer limits of the solar system are designed to study targets like planets, dwarf planets, moons, asteroids and comets, not to conduct astrophysics. But scientists hope future missions will include instruments for surveys of phenomena beyond the solar system.
"With a carefully designed survey, we should be able to produce a definitive measurement of the diffuse light in the local universe and a tight constraint on the light from galaxies in the optical wavebands," Zemcov said.
