The Blue Ring Nebula has perplexed scientists since it was discovered in 2004 by the Galaxy Evolution Explorer (GALEX) satellite. The nebula was only visible in false color renderings of the UV data which appeared as a blue blob in GALEX images. The nebula appears to have a thick ring structure. After multiple observations using GALEX, the 5.1 meter Hale Telescope at Mt. Palomar, the 10 meter telescope at the Keck Observatory, and other space- and ground-based instruments, the data suggest that the nebula consists of two expanding cones of gas being ejected from the collision of two stars.
Video Credit: NASA / JPL / R. Hurt