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##### Asked by: Junaid Levann

science space and astronomy# How many miles can you see before the earth curves?

**3miles**(5 km) away. Geometry tells us that the distance ofthehorizon – i.e. the farthest point the eye can seebeforeEarth curves out beneath our view – depends simply ontheheight of the observer.

Herein, can you see the Earth's curvature?

It is possible to **see** the effect ofthe**curvature** of the **earth** from sea level(shipsdisappearing over the horizon). To actually **see**the**curvature** directly (ie to be able to **see** thehorizonas an arc, rather than a straight line) requires an altitudeofover 50,000 feet.

**you can see**shipson the horizon or land at about 12

**miles**. A roughformula athttp://science.howstuffworks.com Examples: For anobserver standingon the ground with h = 1.70 metres (5 ft 7 in)(average eye-levelheight), the horizon is at a distance of 4.7kilometres (2.9mi).

Similarly, you may ask, how much does the earth curve in 6 miles?

However, it turns out that while the **earthdoescurve** 8 inches in one **mile**, it **does** not take9**miles** to **curve** 72 inches. To show this, let usreturnto the Pythagorean Theorem method used by Harley, butusing**6** feet for the **curvature**.

The **Earth** has a radius of approximately3965**miles**. Using the Pythagorean theorem, that calculates toan**average curvature** of 7.98 inches per **mile**orapproximately 8 inches per **mile** (squared).