星云壁纸
by NASA/JPL-Caltech/M. Seibert (Carnegie Institution for Science)/K. Hoadley (Caltech)/GALEX Team
NASA Image Library · 公有领域（Public Domain）
关于这张图
The Blue Ring Nebula was discovered in 2004 by NASA's Galaxy Evolution Explorer (GALEX) mission. Astronomers think the nebula was created by the merger of two stars, and that we are seeing the system a few thousand years after the merger, when evidence of the collision is still apparent. The blue light in the image shows the debris cloud created by the merger. As the hot cloud of material expanded into space and cooled down, it formed hydrogen molecules that collided with the interstellar medium (the particles occupying the space between stars). These collisions caused the hydrogen molecules …
