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How Fast Is Speed of Light?
3.00e+5 km/s
1079 million km/h · 671 million mph
≈ 100% of the speed of light
The universe's ultimate speed limit. Nothing with mass can ever reach it; anything without mass must travel at it. Light covers the 384,400 km to the Moon in 1.28 seconds. You see the Sun as it was 8 minutes ago. The nearest star as it was 4.2 years ago.
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Did you know?
You see the Sun as it was 8 minutes 20 seconds ago — if it suddenly disappeared, you would not know for over 8 minutes.
How it compares
- Sun to Earth in 8 minutes 20 seconds
- Reaches the Moon in 1.28 seconds
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