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( Earth)
148,940,000&_160;km²&_160;land&_160;&_160;(29.2&_160;%)
Home to millions of species,[11] including humans, Earth is the only place in the universe where life is known to exist. Scientific evidence indicates that the planet formed 4.54 billion years ago,[12][13][14][15] and life appeared on its surface within a billion years. Since then, Earth's biosphere has significantly altered the atmosphere and other abiotic conditions on the planet, enabling the proliferation of aerobic organisms as well as the formation of the ozone layer which, together with Earth's magnetic field, blocks harmful radiation, permitting life on land.[16] The physical properties of the Earth, as well as its geological history and orbit, allowed life to persist during this period. The world is expected to continue supporting life for another 1.5 billion years, after which the rising luminosity of the Sun will eliminate the biosphere.[17] Earth's outer surface is divided into several rigid segments, or tectonic plates, that gradually migrate across the surface over periods of many millions of years. About 71% of the surface is covered with salt-water oceans, the remainder consisting of continents and islands; liquid water, necessary for all known life, is not known to exist on any other planet's surface.[note 4][note 5] Earth's interior remains active, with a thick layer of relatively solid mantle, a liquid outer core that generates a magnetic field, and a solid iron inner core. Earth interacts with other objects in outer space, including the Sun and the Moon. At present, Earth orbits the Sun once for every roughly 366.26 times it rotates about its axis. This length of time is a sidereal year, which is equal to 365.26 solar days.[note 6] The Earth's axis of rotation is tilted 23.4° away from the perpendicular to its orbital plane,[18] producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). Earth's only known natural satellite, the Moon, which began orbiting it about 4.53 billion years ago, provides ocean tides, stabilizes the axial tilt and gradually slows the planet's rotation. A cometary bombardment during the early history of the planet played a role in the formation of the oceans.[19] Later, asteroid impacts caused significant changes to the surface environment.
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Earth Subcategories
Earth Articles
Model Weight Loss Tips - Be Ready to Walk Around Like the Earth is Your Red Carpet! by John Kew
Model weight loss tips these days vary from fasting to eating as much as you can. Most of these are complete lies. Often, however, it requires a whole lot of research to know how much of these tips are true. Your research is now complete! Here are tw...
Yoga And Salute To The Sun by Jeff Seward
One of the all-around yoga exercises is the 12-step salute to the sun. Do it once or twice when you get up in the morning to help relieve stiffness and invigorate the body. Multiple repetitions at night will help you to relax; insomniacs often find t...
HIDDEN DANGERS OF HERBAL SEX PILLS: by Eze ThankGod
In the quest to satisfy his partner sexually, a man that takes sex pills like Viagra may actually be digging his own grave unconsciously. This is because, though these sex pills are marketed as healthy products, they contain some level of unregulated...
Unearthing the Details on Basic Skin Care Information by Laurel Levine
Did you know that you do not need to dig in the earth to obtain important skin care information? Yet you do need to do some digging to obtain the source of one possible ingredient for a vitalizing product. Are you curious to know what that ingredient...
What on Earth are Enzymes? by Dianne Ronnow
Enzymes are the workers in our body that make everything function, by enabling chemical reactions. All living cells contain enzymes. They are hard to visualize, since they are not something tangible, but they are essential to our bodies and our lives...
Managing Your Cholesterol - The Best Way To Prevent Hearth Attacks by Richard Clement
Cholesterol is one of the most familiar medical words today. Everyone knows “something” about it , but mostly cholesterol is associated in our mind with something “bad” and “unwanted” that happens to old and overweight people.The facts show tha...
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