Tropic of Capricorn

The sun on the Tropic of Capricorn

How to use it

1. The line is drawn in orange across the whole map as soon as the page opens.
2. Pan and zoom to follow it. On the web map's Mercator projection, parallels are straight horizontal lines and meridians straight vertical ones.
3. Under the map, read the list of countries whose land the line crosses and the notes about the line.
4. Use the other line pages linked below to compare positions, or the miles per degree calculator for the length of a degree at this latitude.

Why the Tropic of Capricorn is where it is

The Tropic of Capricorn is the southern mirror of the Tropic of Cancer: the southernmost latitude where the sun can be straight overhead, at noon on the December solstice. Between the two tropics lies the only band of the Earth where the sun ever reaches the zenith.

Like its northern twin, it drifts slowly as the axial tilt changes. This page places it at 23.4394° S, the J2000 mean obliquity.

How long the line is

A parallel is a circle whose radius is the distance from the Earth's axis. On the WGS84 ellipsoid that radius is N · cos φ, where N is the prime vertical radius of curvature, which at 23.4394° S is 6,381,518 m. The circumference 2π · N · cos φ comes to 36,787.6 km.

One degree of longitude along it is 102.19 km, or 63.50 miles. The miles per degree calculator gives the same figure for any latitude.

Countries on the line

Testing a point every 0.02° along the line against the Natural Earth 1:50m outlines finds land in 10 countries: Chile, Argentina, Paraguay, Brazil, Namibia, Botswana, South Africa, Mozambique, Madagascar, Australia. At that scale small islands drop out, so the list covers the mainland and larger islands.

• Three large southern deserts sit on or near this latitude: Atacama, Kalahari, and the Australian deserts.

The United States and this line

No part of the 50 states lies south of the equator, let alone near the Tropic of Capricorn. The distance from Denver's capitol to the line along a meridian is 4,346 miles. American Samoa, a US territory, sits at about 14° S, north of the tropic.