| Term | Definition |
|---|
| Universe | all of space and everything in it. Approximately 14 billion years old |
| Galaxy | a cluster of stars, dust and gases held together by gravity |
| Milky way | the spiral galaxy containing the solar system |
| Spiral galaxy | a galaxy with a bulge in the middle and arms that spiral outward in a pinwheel pattern |
| Elliptical galaxy | a galaxy that varies in shape from nearly spherical to flat discs and contain very little dust or gas. |
| Irregular galaxy | no definite shape; may have been involved in a collision with other galaxies |
| Big bang | the initial explosion that resulted in the formation and expansion of the universe. |
| Light year | the distance that light travels in one year |
| Hubble Telescope | he renowned orbiting telescope whose discoveries have forever altered our knowledge of the universe. |
| Orion Arm | the minor arm of the galaxy in which our solar system is located. |
| Gravity | the force that pulls objects toward one another |
| Solar system | Our sun and all the objects that revolve around it. Approximately 5 billion years old |
| Local Group | a group of about 30 galaxies that includes the Milky Way |
| Spiral Arm | Long spiral pattern of bright stars, gas, and dust. Spiral arms extend from the center to the edge of the disk of spiral galaxies. |
Combine with other sets
Share on Facebook
Share on MySpace