Why do astronomers conclude that the Universe is filled with dark energy? Discuss two of the primary reasons
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A series of observations of different processes over the last couple of decades has shown conclusively that the rate of expansion of the Universe is accelerating. The rate of expansion of the Universe must depend on two competing factors. The gravitational effect of baryonic and non-baryonic matter will tend to decelerate the rate of expansion. Since the rate is accelerating, there must be some other effect which counteracts the effects of gravity. This additive energy has been given the name "dark energy".
1) Because the expansion of the Universe is accelerating, and some process must counteract the decelerating influence of matter and gravitation, there must be an unidentified energy source spread through space, termed "dark energy".
2) The density of the Universe is almost exactly equal to the critical density of a flat Universe. Baryonic and non-baryonic matter only account for about 30% of the density needed to achieve critical density. The remainder must come from dark energy, which must comprise about 70% of the density of the Universe.
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Draw the aligned positions of the Sun, Moon, and Earth during a lunar eclipse. Draw the umbra and penumbra. Label all
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A star's ________ parallax is found by using the spectral lines to estimate the spectral class and luminosity of distant stars
Fill in the blank(s) with correct word
Outside a spherically symmetric charge distribution of net charge Q, Gauss's law can be used to show that the electric field at a given distance
A) must be zero. B) must be directed outward. C) acts like it originated in a point charge Q at the center of the distribution. D) must be directed inward. E) must be greater than zero.