## Most recent change of Horizon

Edit made on January 29, 2009 by DerekCouzens at 17:10:42

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Inserted text in green

WW

HEADERS_END

The !* Horizon !* is that imaginary line on the Earth's surface

that marks the furthest point that can be seen from your

vantage point. The exact distance to the horizon depends on

your altitude, and increases as you get higher. That's why

the lookout on a ship was always posted at the highest point

on the ship.

The *exact* values depend, or course, on the local topography,

but we usually get close enough simply by assuming the Earth

is a sphere. We need to know the size of the Earth to do the sums.

Interestingly, the distance to the horizon calculation is

effectively identical to the calculation of orbital velocity.

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Enrichment tasks

Find a formula for the distance to the horizon from a height h on a spherical planet of radius R.

Formulate an experiment to find the minimum height from which people would perceive the horizon to be curved rather than a straight line

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CategoryMaths