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Science
Term | Definition |
---|---|
Astronomy | the scientific study of the universe; it includes the observation and interpretation of celestial bodies and phenomena |
Geocentric | describes the concpet of an Earth-centered universe |
Heliocentric | describes thr view that the sun is at the center of the solar systeam |
Retrograde motion | the apparent westward motion of the planets with respect to the stars |
Ellipse | an oval |
Astronomical Unit (AU) | average distance from Earth to the sun; 1.5 million x 10^8, or 150 million kilometers |
Rotation | the spinning of a body, such as Earth, about its axis |
Revolution | the motion of one body about another, as Earth about the sun |
Precession | a slow motion of Earth's axis that traces out a cone over a period of 26,000 years |
Perihelion | the point in the orbit of a planet where it is closest to the sun |
Aphelion | the place in the orbit of a planet where the planet is farthest from the sun |
Perigree | the point at which the moon is closest to Earth |
Apogee | the point where the moon is farthest from Earth |
Phases of the moon | the progression of changes in the moon's appearance during the month |
Solar eclipse | an eclipse of the sun; a solar eclipse occurs when the moon moves in a line directly between Earth and the sun, casting a shadow on Earth |
Lunar eclipse | an eclipse of the moon; a lunar eclipse occurs when the moon passes through Earth's shadow |
Crater | the depression at the summit of a volcano or that which is produced by a meteorite impact |
Terrestrial planet | any of the Earth-like planets, including Mercury, Venus, Mars, and Earth |
Jovian planet | the Jupiter-like plantes: Jupiter, Saturn, Uranus, and Neptune; these plantes have relatively low densities and are hige gas giants |
Nebula | a cloud of gas and/or dust in space |
Planetesimal | small, irregularly shaped body formed by colliding matter |
Asteroid | a small, rocky body, which can range in size from a few hundred kilometers to less than a kilometer; the asteroids' orbits lie mainly between those of Mars and Jupiter |
Comet | a small body made of rocky and metallic pieces help together by frozen gases; comets generally revolve about the sun in an elongated orbit |
Coma | the fuzzy, gaseous component of a comet's head |
Meteroid | a small, solid particle that travels through space |
Meteor | the luminous phenomenon observed when a meteoroid enters Earth's atmosphere and burns up, popularly called a shoting star |
Meteorite | any portion of a meteoroid that reaches Earth's surface |
Electromagnetic spectrum | the arrangement of electromagnetic radiation according to wavelength |
Photon | a small packet of light energy |
Spectroscopy | the study of the properties of light that depend on wavelength |
Doppler Effect | the apparent change in frequency of electromagnetic or sound waves caused by the relative motions of the source and the observer |
Refracting Telescope | a telescope that uses a lens to bend and concentrate the light from distant objects |
Reflection Telescope | a telescope that concentrates light from distant objects by using a concave mirror |
Radio Telescope | a telescope designed to make observations in radio wavelengths |
Hubble Telescope | a telescope designed to be sent off into space |
Space Shuttle | a reusable low earth spacecraft |