Prior to cruising well beyond Pluto, NASA’s New Horizons spacecraft used an onboard imaging telescope to make the best-ever observations of the universe’s cosmic optical background (COB). That is, the sum of the universe’s emitted optical light from beyond our own Milky Way galaxy. The data was acquired at wavelengths roughly visible to the human eye with the spacecraft’s Long Range Reconnaissance 20.8-centimeter Imager. In our own solar system, astronomers think it’s mostly caused by the reflection of sunlight from tiny particles of dust leftover from collisions in our Main Asteroid Belt. “The sunlight scattered off dust in the solar system is some 100 times brighter than the signal we’re trying to measure,” said Zemcov.

Source: Forbes April 13, 2017 11:12 UTC