This Hubble Space Telescope image shows the central region of the galaxy Arp 220. Some astronomers believe this peculiar galaxy was born in a collision of two spiral galaxies. The collision of clouds and dust may have caused what is known as a starburst, where stars are forming at far above the normal rate for spirals. Another possible explanation for this odd-looking object is that the two bright concentrations of gas are heated by a black hole hidden inside a huge ring of dust and gas.