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Astronomy Definitions and Factiods
Astronomy Definitions
Ascending node: The plane of a planet's orbit (or other solar system object) is usually tilted with respect to the plane defined by the solar system (the ecliptic). These 2 great circles intersect at 2 points. As the planet travels around its orbit, at one of the intersection points it will pass from below the ecliptic plane to above it (i.e. northward). This point is called the ascending node.
Asteroid: A small, mostly rocky body orbiting the Sun. Asteroids range in size from 1000 kilometers in diameter to tiny objects you could hold in your hand. Most asteroids orbit the Sun between Mars and Jupiter, and are the source of most meteorites.
Asteroid family: Group of asteroids with similar orbital elements (distance from the Sun, inclination of the orbital plane to the Earth's orbital plane, and eccentricity of the orbit) thought to be remnants of one larger asteroid parent.
Astrobiology: Study of the origin, distribution, and destiny of life in the universe. These are interdisciplinary studies involving astronomers, astrophysicists, biologists, chemists, geneticists, geologists, paleontologists, planetary scientists, and specialists from other scientific fields. Three broad themes of astrobiology: Is there life elsewhere in the universe? How did life begin and evolve? What is the future for life on Earth and beyond?
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