Article Correctness Is Author's Responsibility: New Horizons Spacecraft Answers Question: How Dark Is Space? 

Newswise imageHow dark is the sky, and what does that tell us about the number of galaxies in the visible universe? A team of scientists has used observations by NASA's New Horizons mission to Pluto and the Kuiper Belt to determine the brightness of the cosmic optical background. Their result sets an upper limit to the abundance of faint, unresolved galaxies, showing that they only number in the hundreds of billions, not 2 trillion galaxies as previously believed.