There is zero gravity at the centre of earth.

Oceanography, the study of oceans, is a mixture of biology, physics, geology and chemistry.

Earth orbits the sun at an average speed of 29.79 km/s (18.51 miles/sec), or about 107 000 km/h (about 67,000 miles/hour).

Earth is the densest planet in the solar system and the only one not named after a god.

the deepest mine in the world is Western Deep Levels near Charletonville, South Africa. It is 4,2km (2.6 miles) deep.

The US has one of the highest fire death rates in the industrialised world, with more than 2 million fires reported each year.

The one place where a flag flies all day, never goes up or comes down, and does not get saluted, is the moon.

The largest iceberg ever recorded was 335km (208 miles) long and 97km (60 miles) wide.

There are 1040 islands around Britain, one of which is the smallest island in the world: Bishop’s Rock.

The magnetic south pole was discovered off the coast of Wilkes Land in Antarctica.

The Dead Sea is 365 m (1,200 ft) below sea level.

Traffic jams of New York, San Francisco and Paris are well known – beaten only by those in Seattle where a driver annually spends 59 hours stuck in traffic.

A dog was the first in space and a sheep, a duck and a rooster the first to fly in a hot air balloon. A dog was the first to parachute.

In 1620, Dutch inventor Cornelius van Drebbel launched the world’s first submarine in the Thames.

Manhattan traffic crawls at an average of 6.2 miles an hour on midtown city streets.

In 1893 J. Frank and Charles E. Duryea produced the first successful gasoline-powered automobile in the United States. They began production of their Duryea in 1896, the same year Henry Ford started operations of his first successful car in Detroit.

A dog was the first in space and a sheep, a duck and a rooster the first to fly in a hot air balloon.

The first mention of soap was on Sumerian clay tablets dating about 2,500 BC. The soap was made of water, alkali and cassia oil.

Only one of the Seven Wonders of the World still survives: the Great Pyramid of Giza.

The world’s first skyscraper was the 10-storey Home Insurance office, built in Chicago in 1885. (During Roman times buildings were up to 8 storeys high.)

Napoleon’s christening name was Italian: Napoleone Buonaparte. He was born on the island of Corsica one year after it became French property. As a boy, Napoleon hated the French.

Excavations from Egyptian tombs dating to 5,000 BC show that the ancient Egyptian kids played with toy hedgehogs.

A green diamond is the rarest diamond.

Hurricanes, tornadoes and bigger bodies of water always go clockwise in the Southern Hemisphere and counterclockwise in the Northern Hemisphere. This directional spinning has to do with the rotation of the earth and is called the Coriolis force.

All the planets in the solar system rotate anticlockwise, except Venus. It is the only planet that rotates clockwise.

The magnetic north pole is near Ellef Ringes Island in northern Canada.

There is no record of a person being killed by a meteorite but animals are occasionally hit.