AST 111 Chapter 1 HW – Flashcards
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What is the meaning of the word cosmos?
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The sum total of all matter and energy, that is, everything within and between all galaxies.
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Earth is made mostly of metals and rocks. Where did this material come from?
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It was produced by nuclear fusion in stars.
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What is nuclear fusion?
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The process of combining lightweight nuclei to make heavier nuclei.
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Why did Carl Sagan say that we are star stuff?
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Nearly every atom from which we are made once (before the solar system formed) was inside of a star.
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What is the Sun mainly made of?
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Hydrogen and helium
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Suppose we imagine the Sun to be about the size of a grapefruit. How big an area would the orbits of the eight planets of the solar system cover?
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The size of a typical campus.
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Which of the following correctly lists our "cosmic address" from small to large?
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Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe
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An astronomical unit is:
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Earth's average distance from the sun.
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The star Betelgeuse is about 600 light-years away. If it explodes tonight,
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we won't know about it until about 600 years from now.
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If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then
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The planets are marble-size or smaller and the nearest stars are thousands of miles away.
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The total number of stars in the observable universe is roughly equivalent to:
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The number of grains of sand on all the beaches on Earth.
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When we say the universe is expanding, we mean that:
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The average distance between galaxies is growing with time.
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If stars existed but galaxies did not:
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We would not exist because we are made of material that required recycling in galaxies.
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Could we see a galaxy that is 20 billion light-years away?
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No, because it would be beyond the bounds of our observable universe.
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The age of our solar system is about:
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one-third of the age of the universe.
