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Chapter 1 Our Place in the Universe - Astronomy

Chapter 1 Our Place in the Universe - Astronomy

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What have we learned?<br />

• How can we know what <strong>the</strong> universe was<br />

like <strong>in</strong> <strong>the</strong> past?<br />

– When we look to great distances, we are<br />

see<strong>in</strong>g events that happened long ago because<br />

light travels at a f<strong>in</strong>ite speed.<br />

• Can we see <strong>the</strong> entire universe?<br />

– No. The observable portion of <strong>the</strong> universe is<br />

about 14 billion light-years <strong>in</strong> radius because<br />

<strong>the</strong> universe is about 14 billion years old.

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