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Astronomy
Term | Definition |
---|---|
Astonomy | the science that deals with the material universe beyond the earth's atmosphere. |
Geocentric | having or representing the earth as a center |
Heliocentric | measured or considered as being seen from the center of the sun |
Retrograde Motion | refers to the backwards motion of planets |
Ellipse | an oval |
Astronomical Unit | average distance from earth to sun |
Rotation | the spinning of a body, such as earth, about its axis |
Revolution | the motion of one body about another |
Precession | he slow, motion of the earth's axis of rotation, caused by the gravitational attraction of the sun and moon, and, to a smaller extent, of the planets |
Perihelion | the point in the orbit of a planet or comet at which it is nearest to the sun. |
Aphelion | the point in the orbit of a planet or a comet at which it is farthest from the sun. |
Perigee | the point in the orbit of a heavenly body, especially the moon, or of an artificial satellite at which it is nearest to the earth. |
Apogee | the point in the orbit of a heavenly body, especially the moon, or of a man-made satellite at which it is farthest from the earth. |
Phases of the Moon | new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter and waning crescent. |
Solar eclipse | the obscuration of the light of the sun by the intervention of the moon between it and a point on the earth |
Lunar Eclipse | the obscuration of the light of the moon by the intervention of the earth between it and the sun |
Crater | the cup-shaped depression or cavity on the surface of the earth or other heavenly body marking the orifice of a volcano. |
Terrestrial Planet | any of the four planets closest to the sun: Mercury, Venus, Earth, or Mars. |
Jovian Planet | any of the four large outer planets: Jupiter, Saturn, Uranus, and Neptune. |
Nebula | a cloud of interstellar gas and dust |
Planetesimal | one of the small celestial bodies that, were fused together to form the planets of the solar system. |
Asteroid | any of the thousands of small bodies of from 480 miles (775 km) to less than one mile (1.6 km) in diameter that revolve about the sun in orbits lying mostly between those of Mars and Jupiter. |
Comet | a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and gas that may form a tail that streams away from the sun |
Coma | the nebulous envelope around the nucleus of a comet |
Meteoroid | any of the small bodies, often remnants of comets, traveling through space: when such a body enters the earth's atmosphere it is heated to luminosity and becomes a meteor. |
Meteor | a transient fiery streak in the sky produced by a meteoroid passing through the earth's atmosphere; a shooting star or bolide |
Meteorite | a mass of stone or metal that has reached the earth from outer space; a fallen meteoroid. |
Electromagnetic Spectrum | he entire spectrum, considered as a continuum, of all kinds of electric, magnetic, and visible radiation, from gamma rays having a wavelength of 0.001 angstrom to long waves having a wavelength of more than 1 million km. |
Photon | he entire spectrum, considered as a continuum, of all kinds of electric, magnetic, and visible radiation, from gamma rays having a wavelength of 0.001 angstrom to long waves having a wavelength of more than 1 million km. |
Spectroscopy | the science that deals with the use of the spectroscope and with spectrum analysis. |
Doppler Effect | the shift in frequency (Doppler shift) of acoustic or electromagnetic radiation emitted by a source moving relative to an observer as perceived by the observer. |
Refracting Telescope | an optical instrument for making distant objects appear larger and therefore nearer |
Reflecting Telescope | has a concave mirror that gathers light from the object and focuses it into an adjustable eyepiece or combination of lenses through which the reflection of the object is enlarged and viewed. |
Radio Telescope | a system consisting of an antenna, either parabolic or dipolar, used to gather radio waves emitted by celestial sources and bring them to a receiver placed in the focus. |
Hubble Telescope | a telescope launched into orbit around the earth in 1990 to provide information about the universe in the visible, infrared, and ultraviolet ranges |
Space shuttle | any of several U.S. space vehicles consisting of a reusable manned orbiter that touches down on a landing strip after an orbital mission |