Science quiz: Can you name the 13 countries that sit on the equator?

close up of the top half of a globe with africa and europe showing — The equator is the imaginary line that runs horizontally across Earth. Can you name the all countries this line runs through?

(Image credit: Kinga Krzeminska/Getty Images)

The equator is the imaginary line that horizontally encircles the middle of Earth, stretching approximately 24,900 miles (40,000 kilometers) long. It's located halfway between the North and South poles, dividing the Northern and Southern hemispheres, with a latitude of 0 degrees.

Humans have known Earth is round for thousands of years — starting with the ancient Greeks, including Pythagoras, around 500 B.C. and confirmed by Aristotle a couple of centuries later. Shortly after this, Eratosthenes became the first person to work out the circumference of the planet.

But it wasn't until the 1700s that the equator was first mapped — albeit slightly off — by a team of French scientists. This same team also confirmed that Earth's circumference is largest at the equator because of a phenomenon known as the equatorial bulge. This is caused by the centrifugal force exerted on the planet by its rotation, which means gravitational force is lower at the equator than elsewhere on Earth.

Hannah Osborne is the planet Earth and animals editor at Live Science. Prior to Live Science, she worked for several years at Newsweek as the science editor. Before this she was science editor at International Business Times U.K. Hannah holds a master's in journalism from Goldsmith's, University of London.

Equator quiz: Can you name the 13 countries that sit on Earth's central line?

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