| Definition | Term |
| Planet that is closest to the sun | |
| The solid inner core of a comet | |
| Loose collection of ice, dust, and small rocky particles whose orbit is usually a very long, narrow ellipse | |
| Region of the solar system between the orbits of Jupiter and Mars where most asteriods are found | |
| Ptolemy supported this type of system | |
| Dark areas of gas on the sun's surface that are cooler than the gases around them. | |
| Region of the sun's atmosphere that we see as a reddish glow | |
| Planet that the Great Red Spot is located on | |
| Eruptions that occur when loops in sunspot regions suddenly connect, releasing large amounts of magnetic energy | |
| Second largest planet in our solar system | |
| Copernicus supported this type of system | |
| Process in which hydrogen atoms join together to form helium, producing energy | |
| Huge reddish loops of gas that often link different parts of sunspot regions | |
| Trapping of heat by the atmosphere | |
| Type of system where Earth and the other planets revolve around the sun | |
| Middle region of the sun's interior | |
| Part of the sun's interior that produces huge amounts of energy | |
| Smallest terrestrial planet | |
| Does Mercury have an atmosphere? | |
| Part of a comet that is made up of the nucleus and coma | |
| Region of the sun's atmosphere that gives off visible light | |