Supernovae are formed when a star explodes, producing an incredibly bright light. As the remnant of the star collides with gas and dust in its path, it releases energy in the form of light.
The hot gas the star leaves behind is known as a supernova remnant; this one is called Vela. This remnant has expanded about 55 light-years from where its supernova exploded, and is one of the closest to our sun. Within this massive cloud of dust lies a tiny star called the Vela pulsar that spins 11 times per second.