Exploration of the Universe |
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acceleration amount angle angular appear astronomical astronomical units atoms binary body bright called celestial equator celestial pole celestial sphere Chapter circle clusters color comets craters density diameter direction disk distance earth earth's atmosphere electrons emitted energy Figure force Galaxy Galileo gases gravitational horizon hydrogen interstellar ionized Jupiter Kepler's km/sec known latitude lens light lines luminosity lunar magnitude main sequence Mars mass measure Mercury meridian meteorites meteoroids meteors mi/sec minor planets mirror moon moon's Mount Wilson moving nebulae Newton's object observed Palomar Observatories parallax particles passes period photographs photons photosphere Pluto produced proper motion radial velocity radiation radio waves reflected regions revolve rotation satellites Saturn semimajor axis sidereal solar eclipse solar system space spectral spectrum speed spherical star's stars stellar sun's sunspot surface telescope temperature third law tion Tycho Uranus Venus visible wavelengths white dwarfs Wilson and Palomar Yerkes Observatory