The study of the universe is called cosmology. Cosmologists study the structure and changes in the present universe. The universe contains all of the star systems, galaxies, gas, and dust, plus all the matter and energy that exists now, that existed in the past, and that will exist in the future. The universe includes all of space and time.
evolution of human understanding of the universe
What did the ancient Greeks recognize as the universe? In their model, the universe contained Earth at the center, the Sun, the Moon, five planets, and a sphere to which all the stars were attached. This idea held for many centuries until Galileos telescope helped people recognize that Earth is not the center of the universe. They also found out that there are many more stars than were visible to the naked eye. All of those stars were in the Milky Way Galaxy. In the early 20th century, an astronomer named Edwin Hubble (Figure 1.1) discovered that what scientists called the Andromeda Nebula was actually over 2 million light years away many times farther than the farthest distances that had ever been measured. Hubble realized that many of the objects that astronomers called nebulas were not actually clouds of gas, but were collections of millions or billions of stars what we now call galaxies. Hubble showed that the universe was much larger than our own galaxy. Today, we know that the universe contains about a hundred billion galaxies about the same number of galaxies as there are stars in the Milky Way Galaxy. (a) Edwin Hubble used the 100-inch reflecting telescope at the Mount Wilson Observatory in California to show that some distant specks of light were galaxies. (b) Hubbles namesake space telescope spotted this six galaxy group. Edwin Hubble demonstrated the existence of galaxies. Click image to the left or use the URL below. URL: Click image to the left or use the URL below. URL:
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everything we can see, even through our most advanced telescopes is in
a) our solar system. b) the local group. c) the milky way galaxy. --> d) the universe.
galileos telescope gave evidence that ___.
a) earth is the center of the solar system. --> b) the sun is the center of the solar system. c) a black hole is the center of the solar system. d) none of the above
the ancient greeks thought the universe had _ at the center and a sphere to which _ were attached.
--> a) earth; the sun, moon, five planets and stars b) sun; the six planets and stars c) a black hole; the entire universe d) none of the above
edwin hubble was the first to realize that the andromeda nebula was another __ outside _.
a) solar system; our solar system b) universe; our universe c) nebula; our nebula --> d) galaxy; out milky way galaxy
galileos telescope revealed galaxies that were not visible with the naked eye.
a) true --> b) false
during the time of galileo, most people thought that earth was the center of the universe.
--> a) true b) false
the idea that there may be more than one universe is called the ___.
a) multiverse theory b) big bang hypothesis --> c) multiverse hypothesis d) big bang theory
edwin hubble found out that what appeared to be large clouds in space were not gas, but
a) large stars --> b) galaxies c) the oort cloud d) the kuiper belt
astronomers think that the universe contains about 100 billion galaxies.
--> a) true b) false
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