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Unit 2 Vocab Pt 1
Unit 2 Vocab for Astronomy, Part 1 of 2
Term | Definition |
---|---|
Astronomy | the scientific study of the universe; it includes the observation/interpretation of celestial bodies and phenomena |
Geocentric | describes the concept of an Earth-centered universe |
Heliocentric | describes the view that the sun is at the center of the solar system |
Retrograde motion | the apparent westward motion of the planets with respect to the stars |
Ellipse | an oval |
Astronomical Unit (AU) | average distance from the Earth to the sun (1.5 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, such as the 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 Earth is closest to the sun |
Apogee | the point where the moon is farthest from the Earth |
Phases of the Moon | the progression of changes in the moon's appearance during the month |
Solar Eclipse | an eclipse of the sun where the moon moves in a line directly between Earth and the sun, casting a shadow on Earth |
Lunar Eclipse | an eclipse of moon that occurs when the moon passes through the Earth's shadow |
Crater | the depression at the summit of a volcano or that which is caused by produced by a meteorite impact |
Terrestrial Planet | any of the Earth-like planets, including Mercury, Venus, Mars, and Earth |
Jovian Planet | the Jupiter-like planets, including Jupiter, Saturn, Uranus, and Neptune; they have relatively low densities and are huge gas giants |
Nebula | a cloud a gas/dust in space |
Planetesimal | the small, irregularly shaped body formed by colliding mater |
Asteroid | a small, rocky body which can range in size from a few hundred kilometers to less than a kilometer; their orbitslie mainly between those of Mars and Jupiter |
Comet | a small body made of rocky and metallic pieces held together by frozens gases; they generally revolve around the sunin an elongated orbit |
Coma | the fuzzy, gaseous component of a comet's head |
Meteoroid | 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 shooting 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 wavelengths |
Doppler Effect | the apparent change in frequency of electromagnetic or sound waves caused by the relative motions of the source and the observer |
Refracting Telesope | a telesope that uses a lens to bend and concentrate the light from distant objects |
Reflecting Telesope | a telesope that concentrateslight fro distant objects by using a concave mirror |
Radio Telesope | a telesope designed to make observations in radio wavelengths |
Hubble Telesope | a telesope that was launched in space by NASA |
Space Shuttle | a rocket-launched space craft able to land like an unpowered aircraft used to make repeated journeys between earth and earth orbit |