They also hope to learn why there is no neutron star or black hole left behind as there usually is when stars like Cas A explode in a supernova. Chandra is a special kind of telescope that can see X-rays , a kind of light that is invisible to your eyes. It is the same kind of light we use to take pictures of bones. Astronomers have already studied Cas A using visible light, radio, infrared, and X-ray telescopes. They have also seen that the cloud contains elements like oxygen, neon, silicon, sulfur, argon, iron, calcium, magnesium, and titanium.
Scientists think supernovae are the source of materials that planets like our earth are built of.
Billions of years from now, the gases we see around Cas A may become a solar system with planets. When very large stars burn up almost all the fuel at their centers, they start burning so hot that only iron is produced. That process uses energy rather than producing it. Then the star starts to shrink inward very fast, building up tremendous pressure, and finally explodes in a final, gigantic blast, blowing the star apart. A black hole is a place in space where the gravity is so strong that it pulls everything in, including light.