 Here's Webb's near and mid-infrared view of ARP 220, an ultra-luminous infrared galaxy with a luminosity of more than a trillion suns. It's 250 million light-years away. It is actually the merging of two spiral galaxies that began their collision about 700 million years ago, sparking an enormous burst of star formation. The cores of the two parent galaxies are 1,200 light-years apart. Near the center, around 200 huge star clusters are packed into a dusty region about 5,000 light-years across. The amount of gas in this tiny region is equal to all of the gas in the entire Milky Way galaxy. The light is so bright that it creates diffraction spikes.