 Hanna's verweap is one of the strangest space objects ever seen. A mysterious glowing green blob of gas is floating in space near a spiral galaxy, IC 2497. The object is so huge that it stretches more than 44,000 light-years to 136,000 light-years from the galaxy's core. It turns out that it's part of a 300,000 light-years long tidal tail that wraps around IC 2497. Our current understanding is that this part of the tail was illuminated by a high-energy beam created by matter falling into the galaxy's central black hole. Our unmistakable emerald hue is caused by ionized oxygen, which glows green.