SomeFacts | Planet Earth

Planet Earth

What is the world’s largest desert?
The Sahara in North Africa covers an area of about 9,269,000 sq km ...

What is the deepest cave?
The Réseau Jean Bernard in France is the deepest cave system. It ...

What is the world’s longest river?
The Nile in north-eastern Africa is 6,617 km (4,112 miles) long. The ...

What is the world’s largest river basin?
The Amazon river basin in South America covers about 7,045,000 sq km ...

Is there a lake under Antarctica?
Scientists have found a lake, about the size of Lake Ontario in North ...

What is the largest inland body of water, or lake?
The salty Caspian Sea, which lies partly in Europe and partly in ...

Which is the deepest lake?
Lake Baikal, in Siberia, eastern Russia, is the world's deepest lake. ...

What is the world’s highest peak?
Mount Everest on Nepal's border with China reaches 8,848 metres ...

Where is the world’s lowest point on land?
The shoreline of the Dead Sea, between Israel and Jordan, is 400 ...

What is the world’s largest high plateau?
The wind-swept Tibetan Plateau in China covers about 1,850,000 sq km ...

What is the world’s largest bay?
Hudson Bay in Canada covers an area of about 1,233,000 sq km (476,000 ...

How much of the world is covered by land?
Land covers about 148,460,000 sq km (57,300,000 sq miles), or 29% of ...

What is the world’s largest island?
Greenland covers about 2,175,000 sq km (840,000 sq miles). ...

What is happening to the world’s rainforests?
The rainforests in the tropics are being destroyed. These forests ...

What is soil erosion?
Natural erosion, caused by running water, winds and other forces, is ...

Can deserts be farmed?
In Israel and other countries, barren deserts have been turned into ...

Can the pollution of rivers harm people?
When factories pump poisonous wastes into rivers, creatures living ...

What is coastal pollution?
Coral reefs and mangrove swamps are breeding places for many fishes. ...

Will global warming affect any island nations?
Coral islands are low-lying. If global warming melts the world's ice, ...

What is air pollution?
Air pollution occurs when gases such as carbon dioxide are emitted ...

How can people protect natural wonders?
People enjoy visiting natural wonders, but they can damage the land, ...

What Japanese wonder attracts pilgrims?
Mount Fuji in Japan is a beautiful volcanic cone. Many people regard ...

Where is the world’s highest mountain range?
The Himalayan range in Asia contains 96 of the world's 109 peaks that ...

What is Meteor Crater?
Meteor Crater in Arizona, America, is a circular depression. It ...

What is the world’s mightiest river?
The Amazon River in South America contains far more water than any ...

What mountains look like dragon’s teeth?
Steep-sided hills made of limestone, found around the town of Guilin ...

Where is the Matterhorn?
The Matterhorn is a magnificent mountain on Switzerland's border with ...

Where can you find ‘smoke that thunders’?
The local name of the beautiful Victoria Falls on the River Zambezi ...

Where is the ‘Great Pebble’?
The word Uluru is an Australian Aboriginal word meaning 'great ...

What is the Great Barrier Reef?
The Great Barrier Reef lies off the northeast coast of Australia. It ...

What are ice shelves?
Ice shelves are large blocks of ice joined to Antarctica's ice sheet ...

What animals live in polar regions?
Penguins are the best known animals of Antarctica. Polar bears, ...

Is the ice around the poles melting?
In parts of Antarctica, the ice shelves began to melt in the 1990s. ...

What are magnetic poles?
The Earth is like a giant magnet, with two magnetic poles. They lie ...

Why are icebergs dangerous to shipping?
Icebergs are huge chunks of ice that break off from glaciers. They ...

Where are the poles?
The Earth is always spinning on its axis, giving us day and night. ...

What is desertification?
Human misuse of the land near deserts, caused by cutting down trees ...

What are oases?
Oases are places in deserts that have water supplies. Some oases have ...

Why do people in deserts wear heavy clothes?
Deserts are often cold at night and heavy clothes keep people warm. ...

What are the main types of desert scenery?
Arabic words are used for desert scenery. Erg is the name for sandy ...

What are dust storms?
Desert winds sweep fine dust high into the air during choking dust ...

Can water change desert scenery?
Thousands of years ago, many deserts were rainy areas and many land ...

What are wadis?
Wadis are dry waterways in deserts. Travellers sometimes shelter in ...

When did the last ice age take place?
The last ice age began about two million years ago and ended 10,000 ...

What is an ice age?
During ice ages, average temperatures fall and ice sheets spread over ...

What are the world’s largest bodies of ice?
The largest bodies of ice are the ice sheets of Antarctica and ...

How much of the world is covered by ice?
Ice covers about 11% of the world's land area. But during the last ...

What are erratics?
Erratics are boulders made of a rock that is different from the rocks ...

What are fiords?
Fiords are deep, steep-sided valleys that wind inland along coasts. ...

Does the sea wear away the land?
Waves wear away soft rocks to form bays, while harder rocks on either ...

What is a baymouth bar?
Some spits join one headland to another. They are called baymouth ...

How can people slow down wave erosion?
Along the beaches at many coastal resorts, walls are built at right ...

What are spits?
Waves and currents transport sediments along coasts. In places where ...

What are deltas?
Deltas are areas of sediments -made up of sand, mud and silt - that ...

What are tributary rivers?
Tributary rivers are rivers that flow into a main river. This swells ...

Why do waterfalls occur?
Waterfalls occur when rivers cross hard rocks. When softer rocks ...

Where do rivers start?
Some rivers start at springs, where ground water reaches the surface. ...

What is biological weathering?
Biological weathering includes the splitting apart of rocks by tree ...

Can plants change the land?
Plant roots can break up the rock. When the seed of a tree falls into ...

Can the Sun’s heat cause mechanical weathering?
In hot, dry regions, rocks are heated by the Sun, but they cool at ...

What are springs?
Springs occur when ground water flows on to the surface. Springs are ...

What is ground water?
Ground water is water that seeps slowly through rocks, such as ...

Does water react chemically with other rocks?
Water dissolves rock salt. It also reacts with some types of the hard ...

What are stalagmites?
Stalagmites are the opposite of stalactites. They are columns of ...

What are pot-holers?
Pot-holes, or swallow holes, are holes in the ground where people ...

What are stalactites?
Water containing a lot of calcium carbonate drips down from the ...

How quickly is the land worn away?
Scientists have worked out that an average of 3.5 cm (1.4 in) is worn ...

What is eohippus?
Eohippus is the name of the dog-sized ancestor of the horse, which ...

Has flesh ever been preserved as a fossil?
In Siberia, woolly mammoths, which lived more than 40,000 years ago, ...

How do you date fossils?
Sometimes, dead creatures are found buried under volcanic ash. The ...

What was Piltdown man?
Some bones, thought to be fossils of an early human ancestor, were ...

What is amber?
Amber is a hard substance formed from the sticky resin of trees. Tiny ...

What are trace fossils?
Trace fossils give information about animals that lived in ancient ...

What is carbonization?
Leaves usually rot quickly after plants die. But sometimes they float ...

How are fossils turned to stone?
When tree trunks or bones are buried, minerals deposited from water ...

What common rocks are used for buildings?
Two sedimentary rocks, limestone and sandstone, and the igneous rock ...

Are some minerals more plentiful than others?
Many useful minerals are abundant. Other less common, but important ...

Is coal a rock?
No. Rocks are inorganic (lifeless) substances. But coal, like oil and ...

What are birthstones?
Birthstones are minerals that symbolize the month of a person's ...

What are the most common rocks?
Sedimentary rocks cover 75% of the Earth's land surface. But igneous ...

What is the hardest mineral?
Diamond, a pure but rare form of carbon, is formed under great ...

Can minerals make you invisible?
People once believed in many superstitions about minerals. In the ...

What are the most valuable minerals?
Gemstones such as diamonds, rubies, sapphires and emeralds are ...

What are hot springs and geysers?
Magma heats water in the ground. The hot water often bubbles up in ...

What are ‘hot spots’?
Some volcanoes lie far from plate edges. They form over 'hot spots' ...

What is an extinct volcano?
Volcanoes that have not erupted in historic times are said to be ...

Do volcanoes do any good?
Volcanic eruptions cause tremendous damage, but soil formed from ...

What is a dormant volcano?
Some volcanoes erupt continuously for long periods. But other active ...

What are volcanoes made of?
Some volcanoes are cone-shaped and made of volcanic ash or cinders. ...

Do earthquakes and volcanoes occur in the same places?
Most active volcanoes occur near the edges of plates that are moving ...

What instruments record earthquakes?
Seismographs are sensitive instruments that record earthquakes. The ...

What is the San Andreas fault?
The San Andreas fault is a long transform fault in California. ...

Can animals sense when an earthquake is about to happen?
Scientists have noticed that animals often behave strangely before an ...

Can scientists predict earthquakes?
In 1975, Chinese scientists correctly predicted an earthquake and ...

What earthquake in modern times caused the most damage?
In 1923, an earthquake struck Tokyo, capital of Japan. About 575,000 ...

Can plates move sideways?
Plates not only move apart or push against each other, they can also ...

How do volcanic islands form in the middle of oceans?
Volcanic islands form when magma rises from the mantle. Lava (the ...

Have fossils helped to prove continental drift?
Fossils of animals that could not possibly have swum across oceans ...

Who first suggested the idea of continental drift?
In the early 1800s, an American, F.B. Taylor, and a German, Alfred ...

How fast do plates move?
Plates move, on average, between I and 10 cm (0.4 and 4 in) a year. ...

What happens when plates collide?
Along deep ocean trenches, one plate is pulled beneath another. There ...

How big are the plates?
The Earth's outer layers are split into seven large plates and about ...

What are plates?
The Earth's hard outer layers are divided into large blocks called ...

When did people first live on Earth?
Hominids (ape-like creatures that walked upright) first appeared on ...

When did mammals first appear?
Mammals lived on Earth from at least the start of the Jurassic ...

When did plants start to grow on land?
The first land plants appeared in the Silurian period. Plants ...

What were the first animals with backbones?
Jawless fishes were the first animals with backbones. They appeared ...

Why is the Cambrian period important?
During the Precambrian, most living creatures were soft-bodied and ...

When did living things first appear on Earth?
The oldest known fossils (of microscopic bacteria) are around 3,500 ...

What was the Earth like after it formed?
The Earth's surface was probably molten (hot and liquid) for many ...