| A | B |
|---|
Constellation,  | Pattern of stars in the sky |
| Galaxy | Giant structure that contains hundreds of billions of stars |
| Universe | All of space and everything in it |
| Light year | Distance light travels in one year |
| Pulsar | Neuron star that produces radio waves |
| Nebula | Large amount of gas and dust in space spread out in an immense volume |
| White dwarf | Remaining hot core of a star after its outer layers have drifted into space |
| Supernova | Explosion of a dying giant or supergiant star |
| Neutron star | Tiny star that remains after a supernova explosion |
| Black hole | Remains of an extremely massive star pulled into a small volume by gravity |
| Quasar | Distant galaxy with a black hole at its center |
Spiral galaxy,  | Galaxy whose arms curve outward in a pinwheel pattern |
Elliptical galaxy,  | Galaxy shaped like a flattened ball |
Irregular galaxy,  | Galaxy that does not have a regular shape |
| Protostar | Contracting cloud of gas and dust in space; earliest stage of a star's life |
| Big Bang | Initial explosion that resulted in the formation of the universe |
