Moving stars occasionally escape from galaxies and

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moving stars occasionally escape from galaxies and from star clusters; and collisions or tidal interactions between galaxies could sweep interstellar matter from them. A theory about the origin and development of the universe is called a _______________. Explanation: Cosmogony. This study refers to theories of the creation of the universe (cosmos). It differs from cosmology in that cosmology is the science of the universe; cosmology includes cosmogony, but it seeks to do much more-- explain the composition of the universe and the laws governing it, while cosmogony seeks to simply explain how the universe came to be.
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The term ______________ embraces not only cosmogony, but also the content and organization of the universe. Explanation: Cosmology. Cosmology is a study of the universe as a whole--what happened in its past and what will happen in the future. The ____________ velocity of galaxies is the component of relative velocity that lies in the line of sight. Explanation: Radial. Remember that velocity consists not only of speed, but also of direction. The radial velocity of a galaxy is its velocity in the line of sight, or in other words its speed straight towards you or away from you. Evidence from the radial velocities of the galaxies acknowledges that the universe is expanding. The first radial velocities of galaxies were measured by V. M. Slipher at the Lowell Observatory. The more distant a galaxy, the greater, in direct proportion, its speed of _______________, as determined by the shift of its spectral lines to the longer (or red) wavelengths. Explanation: Recession. By the 1930's, M.L. Humason and Edwin Hubble had begun to photograph spectra of fainter galaxies and found that in general, the fainter and smaller a galaxy appeared, the higher was its redshift. This was then interpreted to mean that the more distant a galaxy, the higher its speed of recession--in other words, the faster it's moving away from us. This finding is known as the law of red shifts; it is often simply referred to as Hubble's Law. The currently most widely accepted theory for how the universe was formed is the ______ ________ theory. d Explanation: Big Bang. According to the Big Bang theory, the universe started around 12 to 14 billion years ago. There are other theories which have been espoused by big name scientists, but currently the Big Bang theory is the most commonly accepted and well-known explanation for how the universe came to be. In the Big Bang theory, everything originated from a single tiny, infinitely dense and hot and massive point known as a ______________. Explanation: Singularity. Inside of this singularity was contained all of the matter and energy of the universe, which means nothing (not even space) existed outside of it. This singularity then expanded into the universe as we know it today. Note that at the core of each black hole is also thought to exist a singularity. A singularity simply refers to a point of infinite density and infinitesimal (immeasurably small) volume. It is imagined that in a singularity, space and time would become infinitely distorted. There are three main ideas which are seen as supporting evidence by proponents of the Big Bang theory. The
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moving stars occasionally escape from galaxies and from...

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