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20 Cards in this Set

  • Front
  • Back
the whole body of things and phenomena observed or postulated
any of the very large groups of stars and associated matter that are found throughout the universe
galaxy in which we live in
a unit of length in astronomy equal to the distance that light travels in one year in a vacuum or about 5.88 trillion miles (9.46 trillion kilometers)
Edwin Hubble
man who discovered that the universe is expanding
red shift
colour shift in which stars grow further apart
any of numerous clouds of gas or dust in interstellar space
the explosion of a very large star in which the star may reach a maximum intrinsic luminosity one billion times that of the sun
electromagnetic spectrum
the entire range of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves and including visible light
either of the two times each year (as about March 21 and September 23) when the sun crosses the equator and day and night are everywhere of equal length
to diminish in phase or intensity -- used chiefly of the moon
to increase in phase or intensity -- used chiefly of the moon, other satellites, and inferior planets
act of making one complete turn
the time taken by a celestial body to make a complete round in its orbit
any of the small particles of matter in the solar system that are directly observable only by their incandescence from frictional heating on entry into the atmosphere
Asteroid belt
the region of interplanetary space between the orbits of Mars and Jupiter in which most asteroids are found
the alternate rising and falling of the surface of the ocean and of water bodies (as gulfs and bays) connected with the ocean that occurs usually twice a day and is caused by the gravitational attraction of the sun and moon occurring unequally on different parts of the earth
the passing into the shadow of a celestial body
either of the two points on the ecliptic at which its distance from the celestial equator is greatest and which is reached by the sun each year about June 22d and December 22d
a celestial body that consists of a fuzzy head usually surrounding a bright nucleus, that has a usually highly eccentric orbit, and that often when in the part of its orbit near the sun develops a long tail which points away from the sun