Explanation: How can we see what is invisible? Black holes are not easy to see in the dark cosmic night, but astronomers can find them by analyzing their gravitational effects on matter, light and spacetime. The featured image shows an illustration that combines a simulation of a black hole binary system in its final "death-dance" with an astrophotography image of the Tarantula Nebula in the background. Even though black holes don't emit light, they distort the path of light rays, acting like a gravitational lens. As a result, the nebula appears extremely distorted, forming Einstein rings and multiple images. Tarantula...