NASA’s Fermi Helps Calculate Number of Stars in Universe
Astronomers have measured the background light from all the stars in the cosmos and inferred the number of stars created since the dawn of the universe, Using observations from NASA’s Fermi Gamma-ray Space Telescope, scientists discovered emissions from distant blazars – gamma ray-emitting supermassive black holes at the centers of galaxies.
As matter falls into a supermassive black hole, some of it is accelerated outward in the opposite direction. If this jet of energy is pointed at Earth, the Fermi telescope can detect its gamma rays. Gamma rays are the most energetic form of light, sometimes having a billion times more energy than visible light. The study, published in Science Express, found the universe has an average of 1.4 stars per 100 billion cubic light years, putting the average distance between stars at about 4,150 light-years.