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Answers to Exploration Questions: Universe

1. Explain this sentence and how it relates to our understanding of the universe: The farther out into space we look, the further back in time we see.
Answer: We see an object when light is given off or reflected by that object. Light travels, so it takes time for light to travel from the object to our eyes. So the farther away an object is, the longer it takes to travel. We see objects in space as they appeared when the light left it. For example, it takes light from the Sun eight minutes to reach us, so we see it as it appeared eight minutes ago. Objects outside our solar system take years to reach us, so we see them as they appeared years ago.
2. What did astronomers Arno A. Penzias and Robert W. Wilson discover with their microwave radio telescope in 1964? How did their discovery affect our understanding of the universe?
Answer: In 1964, Penzias and Wilson discovered cosmic microwave background radiation, the remnant glow of radiation from the Big Bang. It was the first observational evidence to support the Big Bang theory, and led most astronomers to accept this theory over the “steady state” theory that all matter is created continuously.
3. Explain how this graph shows the effects of dark energy. How does this graph represent a major change in how scientists once thought of the expanding universe?
Answer: This graph shows that the expansion of the universe is accelerating. Until scientists discovered that the expansion of the universe was accelerating, most thought the force of gravity would slow the expansion of the universe. From this discovery, scientists infer a mysterious pressure they call dark energy.

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