Splitting the World in Half: Hemispheres!

Imagine slicing an orange perfectly in half. You get two equal pieces. Now imagine doing that to the whole planet Earth! Have you ever wondered why people in Australia have summer in December while people in the UK shiver through winter at the same time? The answer is all about which 'half' of the Earth you live on. Today you will find out what those halves are called and how we name them.

The word 'hemisphere' comes from Greek and means 'half a sphere'. A sphere is a perfectly round 3D shape, like a ball. Earth is a sphere, so a hemisphere is simply half of Earth. Geographers — people who study the Earth — use two special imaginary lines to cut the globe into four hemispheres. **The Equator: Top and Bottom** The equator is an imaginary line that runs around the exact middle of the Earth, halfway between the North Pole and the South Pole. It divides Earth into two halves: • The Northern Hemisphere — everything north of (above) the equator. Europe, North America, most of Asia, and North Africa are here. • The Southern Hemisphere — everything south of (below) the equator. South America, Australia, Antarctica, and southern Africa are here. **The Prime Meridian: Left and Right** The Prime Meridian is another imaginary line. It runs from the North Pole to the South Pole and passes through Greenwich, London. It divides Earth into two more halves: • The Western Hemisphere — everything to the west of the Prime Meridian. North America and South America are mostly here. • The Eastern Hemisphere — everything to the east of the Prime Meridian. Europe, Africa, Asia, and Australia are mostly here. **Four Hemispheres Together** Because both lines cross each other, every place on Earth actually sits in TWO hemispheres at once — one north or south, and one east or west. For example, London, UK is in both the Northern Hemisphere and the Eastern Hemisphere. Sydney, Australia is in both the Southern Hemisphere and the Eastern Hemisphere. New York, USA is in both the Northern Hemisphere and the Western Hemisphere. That is why seasons are opposite on either side of the equator — the Northern and Southern Hemispheres receive sunlight at different angles at the same time of year.