What is the significance of the name earth

Many volcanoes form as seafloor crust smashes into and slides beneath continental crust. When plates of continental crust collide, mountain ranges such as the Himalaya are pushed toward the skies. Earth's atmosphere is 78 percent nitrogen, 21 percent oxygen, and one percent other gases such as carbon dioxide, water vapor, and argon.

Much like a greenhouse, this blanket of gases absorbs and retains heat. On average, Earth's surface temperature is about 57 degrees Fahrenheit; without our atmosphere, it'd be zero degrees. In the last two centuries, humans have added enough greenhouse gases to the atmosphere to raise Earth's average temperature by 1.

This extra heat has altered Earth's weather patterns in many ways. The atmosphere not only nourishes life on Earth, but it also protects it: It's thick enough that many meteorites burn up before impact from friction, and its gases—such as ozone—block DNA-damaging ultraviolet light from reaching the surface.

But for all that our atmosphere does, it's surprisingly thin. Ninety percent of Earth's atmosphere lies within just 10 miles of the planet's surface. We also enjoy protection from Earth's magnetic field, generated by our planet's rotation and its iron-nickel core.

This teardrop-shaped field shields Earth from high-energy particles launched at us from the sun and elsewhere in the cosmos. But due to the field's structure, some particles get funneled to Earth's Poles and collide with our atmosphere, yielding aurorae, the natural fireworks show known by some as the northern lights.

Earth is the planet we have the best opportunity to understand in detail—helping us see how other rocky planets behave, even those orbiting distant stars. As a result, scientists are increasingly monitoring Earth from space. NASA alone has dozens of missions dedicated to solving our planet's mysteries. At the same time, telescopes are gazing outward to find other Earths. Thanks to instruments such as NASA's Kepler Space Telescope, astronomers have found more than 3, planets orbiting other stars, some of which are about the size of Earth , and a handful of which orbit in the zones around their stars that are just the right temperature to be potentially habitable.

Other missions, such as the Transiting Exoplanet Survey Satellite, are poised to find even more. All rights reserved. Earth Earth seems to fill the sky in this image taken by the crew of Apollo 17 in Share Tweet Email. Read This Next Wild parakeets have taken a liking to London. Animals Wild Cities Wild parakeets have taken a liking to London Love them or hate them, there's no denying their growing numbers have added an explosion of color to the city's streets.

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Live TV. This Day In History. History Vault. The Rise and Fall of Planet Pluto. Who is the Miranda warning named for? Accessed 11 Nov. English Language Learners Definition of earth Entry 2 of 2. See the full definition for earth in the English Language Learners Dictionary. Nglish: Translation of earth for Spanish Speakers.

Britannica English: Translation of earth for Arabic Speakers. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Log in Sign Up. Save Word. Definition of earth Entry 1 of 2. Definition of earth Entry 2 of 2. Examples of earth in a Sentence Noun The moisture will eventually fall to earth in the form of rain or snow. We could feel the earth shake. First Known Use of earth Noun before the 12th century, in the meaning defined at sense 1 Verb , in the meaning defined at transitive sense 1.