It all begins with a massive star, which has about 10 times more mass than our own sun. This star is burning through its nuclear fuel at a prodigious rate, and it is producing a lot of heat and light. As the star ages, it begins to expand and cool. This expansion causes the star's outer layers to become less dense.

2. Core collapse

When the star's outer layers are sufficiently rarefied, the core of the star begins to collapse. The collapse causes the star's core to become very dense and hot. This density and temperature combination leads to fusion reactions, but the energy of the fusion reactions is not enough to support the weight of the overlying material. The core continues to collapse.

3. Supernova explosion

When the star's core collapses, it creates a shock wave. The shock wave propagates through the star's outer layers, and it eventually causes the star to explode. The supernova explosion is extremely powerful. It can release more energy than the sun will produce in its entire lifetime.

4. Remnant formation

After the supernova explosion, the core of the star is left behind. The core is extremely dense and hot, and it is known as a white dwarf. The white dwarf may gradually cool and become a black dwarf, or it may detonate in a future Type Ia supernova.

The outer layers of the star are ejected into space by the supernova explosion. These layers are heated to very high temperatures, and they emit a wide range of electromagnetic radiation, including visible light, ultraviolet light, and X-rays. The supernova remnant can last for thousands or even millions of years.