Explanation:
The closest supernova remnant to Earth — the Gum Nebula.
Although the Gum Nebula is large and very close to us, it is actually quite difficult to see. This is because we are located within this glowing region filled with hot hydrogen gas, with the front edge 450 light-years away and the back edge 1,500 light-years away. This image, which covers 40 degrees in H-alpha, shows a very faint glowing region that is easily obscured by the starlight of our own Milky Way galaxy. Scattered across the sky near the southern constellations of Puppis and Vela, this complex region is considered to be the remnant of a supernova explosion from over a million years ago. Named after the Australian astronomer Colin Stanley Gum (1924-1960), pointing your mouse at this magnificent photo [on the original website] reveals the celestial bodies hidden within the nebula, including the remnants of the Vela supernova explosion. Interestingly, the Gum Nebula still has many mysteries to be solved, including the exact timing of the supernova explosion and exactly how many supernova events occurred to form this nebula.
NASA Website: