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Powers of Ten & Units

Chapter 1 · Measuring the UniverseFree

Zoom from quarks to galaxies.

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The nearest star to Earth (after the Sun) is Proxima Centauri, about 4.24 light-years away. The Earth's diameter is about 12,742 km.

How many Earths, laid side by side, would it take to reach Proxima Centauri?

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