How Much Do You Know About the Planet Earth?

Earth is the third planet from the sun. The order of the planets in our solar system is: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

The Earth's rotation is slowing. However, it is happening very slowly, at the rate of 17 milliseconds per century.

Some planets have many moons. The earth only has one.

Earth's atmosphere is is 78% nitrogen and 21% oxygen. It contains trace amounts of other gases.

The earth's surface is 70% covered by water. This includes the world's oceans, lakes and rivers.

The first of the world's life developed in the oceans. These were simple single-celled creatures that evolved to form all of the life on earth.

Scientists think the world has an inner core, a solid mantle and an outer crust that varies in thickness. Its crust is divided into tectonic plates which are in constant motion.

In our solar system there are rocky terrestrial planets, massive gas giants and frigid ice giants. Earth is a rocky terrestrial planet.

Scientists divide earth's history into 4 eons. The first is the Hadean, during which the Earth and Moon were formed. The earth was scorching hot and inhospitable to life.

Pangaea was an ancient supercontinent that split into the continents Laurentia, Baltica, Siberia and Gondwana. Over time, these became the continents as we know them today.

Life started in the oceans with simple organisms. During the Cambrian Explosion, the first vertebrate organisms evolved from them, including the first fish.

There have been 5 mass extinctions throughout earth's history. In all of them, over half of all life on earth was wiped out each time.

Humans are a relatively new addition to the planet Earth. The roughly 3.9 – 2.55 million-year-old Australopithecus Afarensis, whose remains were found in Africa, is the oldest evidence of hominids found so far.

Homo sapiens is the scientific name of modern man. Between 35,000 and 100,000 years ago homo sapiens migrated from Africa to Australia and Eurasia.

Humans developed agriculture for the first time in the Fertile Crescent, in the Middle East. This occurred between 8500 and 7000 BC and was the start of modern civilization.

Volcanoes form in areas where tectonic plates either collide or drift apart. This movement creates pressure which causes explosions of magma from the earth's surface in the form of volcanoes.

6 main kinds of animals live on earth. These are mammals, invertebrates, fish , birds, amphibians and reptiles.

All living things on earth store genetic information in DNA and RNA. This provides evidence for the shared ancestry of all living things on earth.

The seasons are opposite in the Northern in Southern Hemisphere. When it is winter in the Northern Hemisphere, it is summer in the Southern Hemisphere.

While subtropical deserts are the hottest and most well-known, there are actually 4 types of deserts. The types of deserts are polar, coastal, cold winter and subtropical.

On Earth there are 6 major climate regions. These are Mediterranean, Temperate, Polar, Arid, Tropical and Tundra.

Polar climates are cold and dry all year long and few animals and plants live there. Polar climates are found around the North and South poles.

Much of North America is temperate, though a few types of climates are represented there. This climate type has cold winters and mild summers and supports diverse plant and animal life.

Tropical regions have an incredible diversity of plant and animal life. They include the jungles of South America and Africa, Southeast Asia and the Pacific islands.

At over 29,000 feet high, Mount Everest is the world's tallest mountain. It sits on the border of China and Nepal.

Dallol, Ethiopia is said to be one of the hottest, if not the hottest inhabited place in the world. This remote desert location is only accessible by camels and known for its beautiful landscape and scorching average temperature of 106 degrees Fahrenheit.

The Veryovkina Cave is located in the country of Georgia in the Western Caucasus Mountains. At over 7,200 feet deep, it is the deepest known cave on earth.

The earth is roughly 4.5 billion years old. Scientists have determined this via a process called radiometric dating.

The coldest permanently inhabited place is Oymyakon, a rural eastern Russian village. In January, the average temperate is -58 degrees Fahrenheit.

A ground temperature of over 200 degrees Fahrenheit was recorded in Death Valley, California in 1972. So far, this is the hottest ground temperature ever recorded on earth.

The earth's oceans are split into five sections. These are the Atlantic Ocean, Pacific Ocean, Indian Ocean, Arctic Ocean and Antarctic (Southern) Ocean.

The Mariana Trench is located in the Pacific Ocean. At nearly 36,000 feet deep, it is the deepest natural point on earth.

Despite all the legends about Santa Claus living at the North Pole, there is no land there. The geographic North Pole is located in the Arctic Ocean.

The geographic South Pole is located on the continent of Antarctica. It is the fifth-largest continent.

The highest permanent human settlement on earth is the town of La Rinconada, Peru in the Peruvian Andes. It sits at an elevation of 16,732 feet.