South of Antares, at the tail of Scorpio, which is rich in nebulae, there is a radiation nebula named IC 4628. The energy emitted by a massive hot star with a history of only a few million years nearby in the ultraviolet band ionizes the atoms in the nebula, and the ionized ions will capture the redundant electrons around. This recombination process will produce visible nebula glow, which is mainly manifested by the red radiation of hydrogen atoms. It is estimated that the distance is 6000 light years, and the upper area is about 250 light years wide, which visually covers about four full moon-wide areas. This nebula is also numbered Gum 56 to commemorate the Australian astronomer Gum. However, astronomers who like seafood may know that this cosmic cloud also has a nickname "Lobster Nebula".