5.5 Astrophysics and cosmology


Astronomical distances are expressed using three specialist units: Astronomical unit: average distance between the Earth and the Sun Light-year: distance travelled by light in a vacuum in a time of one year Parsec: the distance from which a base length (radius) of 1...

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Astrophysics definitions: Planets: an object in orbit around a star which has 3 characteristics: Mass large enough for its gravitational attraction to give it a round shape No fusion reactions Has cleared its orbit of most other objects, e.g. asteroids Planetary...

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