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Unit 3
The Solar System
| Question | Answer |
|---|---|
| Solar System | The Sun and all of the planets and other bodies that travel around it. |
| Heliocentric | Sun-centered. |
| Geocentric | Describes something that uses Earth as the reference point. |
| Parallax | An apparent shift in the position of an object when viewed from different locations. |
| Gravity | A force of attraction between objects that is due to their mass. |
| Orbit | A path that a body follows as it travels around another body in space. |
| Aphelion | In the orbit of a planet or another body in the solar system, the point that is farthest from the Sun. |
| Perihelion | The point in which the point of a planet at which the planet is closest to the Sun. |
| Centripetal force | The inward force required to keep a particle or an object moving in a circular path. |
| Solar nebula | A rotating cloud of gas and dust from which the Sun and planets formed. |
| Planetesimal | A small body from which a planet originated in the early stages of development of the solar system. |
| Nuclear fusion | The process by which nuclei of small atoms combine to form a new, more massive nucleus; the process releases energy. |
| Sunspot | A dark area of the photosphere of the Sun that is cooler than the surrounding areas and that has a strong magnetic field. |
| Solar flare | An explosive release of energy that comes from the Sun and that is associated with magnetic disturbances on the Sun's surface |
| Prominence | A loop of relatively cool, incandescent gas that extends above the photosphere and above the Sun's edge as seen from Earth. |
| Terrestrial planet | One of the highly dense planets nearest to the Sun; Mercury, Venus, Earth and Mars. |
| AU | The average distance between Earth and the Sun; approximately 150 million kilometers symbol |
| Gas giant | A planet that has a deep massive atmosphere, such as Jupiter, Saturn, Uranus or Neptune. |
| Planetary ring | A disk of matter that encircles a planet and consists of numerous particles in orbit, ranging in size from dust grains up to objects tens of meters. |
| Dwarf planet | A celestial body that orbits the Sun, is round because of its own gravity, but has not cleared its orbital path. |
| Kuiper Belt | A region of the solar system that is just beyond the orbit of Neptune and that contains small bodies made mostly of ice. |
| Kuiper Belt object | One of the hundreds or thousands of minor planet- sized objects that orbit the Sun in a flat belt beyond Neptune's orbit. |
| Comet | A small body that gives off gas and dust as it passes close to the Sun; a typical comet moves in an elliptical order around the Sun and is made of Dust and frozen gases. |
| Oort cloud | A spherical region that surrounds the solar system, that extends from the Kuiper belt to almost halfway to the nearest star, and that contains billions of comets. |
| Asteroid | A small rocky body that orbits the Sun; most asteroids are .located in a band between the orbits of Mars and Jupiter |
| Meteoroid | a relatively small rocky body that travels through space. |
| Meteor | A bright streak of light that results when a meteoroid burns up in Earth's atmosphere. |
| Meteorite | A meteoroid reaches Earth's surface without burning up completely. |