| A | B |
|---|
| Solar System | Consists of the sun, the planets, their moons, and a variety of smaller objects. |
| Planet | A object that is round |
| Astronomical Unit | Equals the average distance 150,000,000 km |
| dwarf planet | An object that orbits the sun, |
| planetesimal | The rock and ice formed small bodies in space. |
| core | The central region of the sun. |
| nuclear fusion | A process that occurs on the sun whre hydrogen atoms join to form helum. |
| radiation zone | A region on the sun of very tightly packed gas where energy moves mainly int he form of electromagnetic radiation. |
| convection zone | The outermost layer of the sun's interior. |
| photosphere | The inner layer of the sun's atmosphere. |
| chromosphere | The middle layer of the sun's atmosphere. |
| corona | The outer layer of the sun that looks like a white halo around the sun. |
| solar wind | Electrically charged particles from the sun that extend into space. |
| sunspot | Dark spots on the sun which are areas of gass on the sun's surface that are cooler than the gased around them. |
| prominence | Huge loops of gas that link different parts of the sunspot regions. |
| solar flare | Magnetic energy heats gas on the sun to millions of degrees Celsius, causing the gas to erupt into space. |
| terrestrial planet | From the Latin word, "terra" meaning Earth. |
| greenhouse effect | This trapping of heat by the atmosphere. |
| gas giant | These planets are so large and are often referred to by this name. Due to size and composition. |
| ring | A thin disk of small particles of ice and rock. |
| asteroid belt | A region of the solar system between Mars and Jupiter. |
| Kuiper belt | A region beyond Neptune's orbit. |
| Oort Cloud | This area in space stretches out more than 1,000 times the distance between the sun and Neptune. |
| comets | A loose collection of ice, dust, and small rocky particles whose orbits can be very long and narrow. |
| coma | Clouds of gas and dust form a fuzzy outer lay on a comet. |
| nucleus | The solid inner core of a comet. |
| asteroid | Rocky objects in space most of which are too small and too numerous to be considered planets or dwarf planets. |
| meteroid | Chunks of rock or dust smaller than asteroids |
| meteor | When a meteroid enters the earth's atmosphere and creates friction with the air which produces heat and light that we can see. |
| meteorite | Meteroids that pass through the atmosphere and land on Earth's surface. |
