Book 6, Question 24
Why Is the Horizon a Straight Line?
Earth is huge and curved. From the beach, you only see a tiny slice of that curve. So the far edge of the water looks like a straight line.
From the book
Page from A Million Whys Book 6
More fun facts
- Your line of sight to the horizon just touches the curved Earth at a single point.
- If your eyes are about 2 meters above the water at the beach, the horizon is only about 5 kilometers away.
- From the International Space Station, astronauts see a patch of Earth about 2,000 miles across, almost the whole United States.
- The space station moves about 300 miles every minute, so places on the ground pass out of view in just a few minutes.
- Far out in space, Earth looks small, so you would have to look almost straight down to see its edge.
Sources: NASA, NASA Science, Scientific American
Questions kids ask
How far away is the horizon at the beach?
If your eyes are about 2 meters up, the horizon is roughly 5 kilometers away.