Did you know that some of the brightest sources of light in the sky come from black holes in the centers of galaxies? It sounds contradictory, but it’s true! See how our Fermi Gamma-ray Space Telescope helps us spot these objects: https://nasa.tumblr.com/post/171449548004/the-universes-brightest-lights-have-some-dark[fb_vid id=”10156070247296772″]