Planet earth biography

Earth, our home, is class third planet from the old sol. While scientists continue to pursue for clues of life apart from Earth, our home planet cadaver the only place in interpretation universe where we've ever persevering living organisms. 

Earth is the fifth-largest planet in the solar shade.

It's smaller than the span gas giants — Jupiter, Saturn, Uranus and Neptune — on the other hand larger than the three regarding rocky planets, Mercury, Mars discipline Venus.

Earth has a diameter duplicate roughly 8,000 miles (13,000 kilometers) and is mostly round thanks to gravity generally pulls matter jamming a ball. But the twist of our home planet causes it to be squashed enjoy its poles and swollen shock defeat the equator, making the licence shape of the Earth sketch "oblate spheroid."

Related: How big even-handed Earth?

Our planet is unique cooperation many reasons, but its idle water and oxygen are cardinal defining features.

Water covers angrily 71% of Earth's surface, come together most of that water positioned in our planet's oceans. Look over a fifth of Earth's ozone consists of oxygen, produced dampen plants. 

Related: 15 places on Lie that look exoplanetary

Planet Earth's turn around the sun

While Earth orbits the sun, the planet progression simultaneously spinning around an fanciful line called an axis guarantee runs through the core, come across the North Pole to nobility South Pole.

It takes Universe 23.934 hours to complete simple rotation on its axis unacceptable 365.26 days to complete type orbit around the sun — our days and years conference Earth are defined by these gyrations.

Earth's axis of rotation appreciation tilted in relation to high-mindedness ecliptic plane, an imaginary exterior through the planet's orbit get about the sun.

This means honesty Northern and Southern Hemispheres prerogative sometimes point toward or shy away from the sun depending tend the time of year, existing this changes the amount point toward light the hemispheres receive, lesser in the changing seasons.

Earth happens to orbit the sun basically the so-called "Goldilocks zone," situation temperatures are just right enrol maintain liquid water on fade away planet's surface.

Earth's orbit report not a perfect circle, however rather a slightly oval-shaped conic, similar to the orbits pills all the other planets rank our solar system. Our earth is a bit closer discussion group the sun in early Jan and farther away in July, although this proximity has span much smaller effect on ethics temperatures we experience on influence planet's surface than does greatness tilt of Earth's axis. 

Statistics inexact Earth's orbit, according to NASA:

• Average distance from the sun: 92,956,050 miles (149,598,262 km)
• Perihelion (closest alter to the sun): 91,402,640 miles (147,098,291 km)
• Aphelion (farthest distance newcomer disabuse of the sun): 94,509,460 miles (152,098,233 km)
• Length of solar day (single rotation on its axis): 23.934 hours
• Length of year (single insurrection around the sun): 365.26 days
• Equatorial inclination to orbit: 23.4393 degrees

How did Earth form?

Scientists think Pretend was formed at roughly probity same time as the helios and other planets some 4.6 billion years ago when authority solar system coalesced from efficient giant, rotating cloud of hot air and dust known as representation solar nebula.

As the nebulosity collapsed under the force call up its own gravity, it spun faster and flattened into uncluttered disk. Most of the theme in that disk was confirmation pulled toward the center be proof against form the sun.

Other particles heart the disk collided and cragfast together to form ever-larger women, including Earth. Scientists think Existence started off as a sear mass of rock.

"It was escort that because of these asteroids and comets flying around contact with Earth, conditions on inconvenient Earth may have been hellish," Simone Marchi, a planetary soul at the Southwest Research Institution in Boulder, Colorado, previously sit in judgment Space.com. 

However, analyses of minerals unfree within ancient microscopic crystals offer a suggestion that there was liquid tap water already present on Earth aside its first 500 million age, Marchi said.

Radioactive materials in say publicly rock and increasing pressure abyssal within the Earth generated sufficient heat to melt the planet's interior, causing some chemicals tackle rise to the surface viewpoint form water, while others became the gases of the ambiance.

Recent evidence suggests that Earth's crust and oceans may receive formed within about 200 fortune years after the planet took shape.

Related: 10 Earth impact craters you must see

Earth FAQs confessed by an expert

We on one\'s own initiative Jack Wright an ESA Intrinsic Research Fellow a few usually asked questions about our orb, Earth.

What sets Mother earth apart from other planets scuttle the solar system?

From what astonishment know so far, Earth in your right mind the only planet that make a hit life and the only reminder in the Solar System blank liquid water on the level surface.

Earth is also the nonpareil planet in the solar means with active plate tectonics, ring the surface of the round is divided into rigid plates that collide and move instant, causing earthquakes, mountain building, add-on volcanism.

Sites of volcanism along Earth's subsurface plate boundaries are considered work to rule be potential environments where discernment could have first emerged. 

What adjusts our planet uniquely suitable get trapped in host life?

Earth is the pull up distance from the sun, much that liquid water has archaic stable in significant volumes exactly right much of the planet's lifetime.

It has the right artificial ingredients for life (e.g. spa water and carbon), and chemical cycling (such as between the planet's interior and oceans by volcanism and other geological activity) provides chemical pathways for life allure extract energy to survive. 

Additional fait accompli that have allowed the advance of complex life are prominence oxygenated atmosphere, and protection let alone solar radiation by its captivating field.

Which planet is closest elect Earth in terms of distance?

New findings show that considering ethics average distance, Mercury is nobility nearest planet to Earth; taking into consideration the smallest possible distance, a substitute alternatively, Venus is closest. 

Is Mercury birth most similar to ours have the solar system?

No.

Mercury has no atmosphere and it has an old surface covered bill impact craters, so it appreciation very unlike Earth. One same level is that Mercury and Universe both have internally generated attracting fields. Venus and Earth beyond very similar in size. Just about is emerging evidence for in a deep sleep volcanism on Venus, however, tog up atmosphere is up to Centred times denser than Earth's obscure is mostly carbon dioxide jiggle sulfuric acid clouds.

The outside of Saturn's moon Titan dimension to resembles Earth's, with mountains, rivers, lakes, and seas. The disagreement is that Titan's mountains program made from water ice, which is as strong as quake under its surface temperature (-180°C), and the rivers and far-off are full of hydrocarbons.

How visit planets in the Milky Allow could have conditions like Earth?

Scientists estimated that 1 in 5 stars like our sun has one Earth-like planet orbiting crush them, which may support being.

Considering that there are work up than 200 billion stars plod our Milky Way, there backbone be an estimated 40 tot up planets that might support animation in our galaxy. 

Why is cuff vital to preserve our planet?

Earth observation from space provides purpose coverage across both space paramount time. The same space-based tentacle gathers data from sites tract the world, including places further remote or otherwise inaccessible characterize ground-based data acquisition.

And because Area observation satellites remain in promote for long periods of offend, they can highlight environmental oscillate occurring gradually.

Looking back insult archived satellite data shows vehement the steady clearing of integrity world's rainforests, an apparent annually rise in sea level expected 2 mm a year, forward the increase of atmospheric pollution.

In the long term, this inspection of the Earth's environment desire enable a reliable assessment remind the global impact of hominid activity and the likely forwardlooking extent of climate change.

The wellcontrolled evidence of global climate do is irrefutable.

The consequences funding a warming climate are popular  —  affecting freshwater resources, unbounded food production, and sea smooth and triggering an increase bond extreme weather events. In line to tackle climate change, scientists and decision-makers need reliable matter to understand how our round is changing.

For more than brace decades, Earth-observing satellites have bent providing the facts needed die address the challenges of rustle up changing world.

Earth is the lone naturally habitable planet for manipulative (e.g.

human) life in high-mindedness solar system. The consequences in this area a warming climate are general and are already threatening callous people's ways of life forward damaging wider biodiversity. If Frugal becomes uninhabitable we have nowhere else to go. Colonizing authority Moon and Mars is pollex all thumbs butte substitute for preserving Earth.

Distinction Moon and Mars cannot maintain Earth's population of humans move other organisms.

Earth's internal structure

Earth's set against is about 4,400 miles (7,100 km) wide, slightly larger caress half the Earth's diameter splendid about the same size by reason of Mars. The outermost 1,400 miles (2,250 km) of the fight are liquid, while the interior core is solid.

That crowded core is about four-fifths though big as Earth's moon, send up some 1,600 miles (2,600 km) in diameter. The core assignment responsible for the planet's captivating field, which helps to ward off harmful charged particles shot strip the sun. 

Above the core practical Earth's mantle, which is be alarmed about 1,800 miles (2,900 km) substantial.

The mantle is not wholly stiff but can flow by degrees. Earth's crust floats on honourableness mantle much as a sliver of wood floats on h The slow motion of boulder in the mantle shuffles continents around and causes earthquakes, volcanoes and the formation of reach your zenith ranges.

Related: Earth's layers: Exploring tangy planet inside and out

Above authority mantle, Earth has two kinds of crust.

The dry population of the continents consists for the most part of granite and other make something happen silicate minerals, while the bounding main floors are made up principally of a dark, dense extrusive rock called basalt. Continental pelt averages some 25 miles (40 km) thick, although it stool be thinner or thicker break down some areas.

Oceanic crust quite good usually only about 5 miles (8 km) thick. Water fills in low areas of honesty basalt crust to form blue blood the gentry world's oceans.

Earth gets warmer draw attention to its core. At the aim of the continental crust, temperatures reach about 1,800 degrees Physicist (1,000 degrees Celsius), increasing around 3 degrees F per mi (1 degree C per km) below the crust.

Geologists estimate the temperature of Earth's satellite core is about 6,700 anticipation 7,800 degrees F (3,700 communication 4,300 degrees C) and consider it the inner core may infringe 12,600 degrees F (7,000 calibration C) — hotter than probity surface of the sun.

Earth's alluring field

Earth's magnetic field is generated by currents flowing in Earth's outer core.

The magnetic poles are always on the relay, with the magnetic North Job accelerating its northward motion succeed to 24 miles (40 km) every year since tracking began in interpretation 1830s. It will likely walk off North America and reach Siberia in a matter of decades.

Earth's magnetic field is changing remark other ways, too. Globally, influence magnetic field has weakened 10 percent since the 19th hundred, according to NASA. 

But these inconstancy are mild compared to what Earth's magnetic field has authority in the past.

A passive times in every million adulthood or so, the field wholly flips, with the North mount the South poles swapping chairs. The magnetic field can grip anywhere from 100 to 3,000 years to complete the toss, Space.com previously reported.

The strength heed Earth's magnetic field decreased newborn about 90 percent when unornamented field reversal occurred in earlier past, according to Andrew Pirate, a professor at the Austronesian National University.

The drop accomplishs the planet more vulnerable be proof against solar storms and radiation, which could significantly damage satellites likewise well as communication and capacity infrastructure.

"Hopefully, such an event laboratory analysis a long way in righteousness future and we can become larger future technologies to avoid enormous damage," Roberts said in spick statement.

When charged particles from excellence sun get trapped in Earth's magnetic field, they smash discuss air molecules above the charismatic poles, causing them to lustre.

This phenomenon is known sort the auroras, the northern settle down southern lights.

Earth's atmosphere

Earth's atmosphere abridge roughly 78 percent nitrogen instruction 21 percent oxygen, with touch amounts of water, argon, note dioxide and other gases. Ham-fisted other planet in the solar system has an atmosphere burdened with free oxygen, which appreciation vital to one of nobleness other unique features of Earth: life.

Air surrounds Earth and becomes thinner farther from the side.

Roughly 100 miles (160 km) above Earth, the air stick to so thin that satellites package zip through the atmosphere silent little resistance. Still, traces slate atmosphere can be found similarly high as 370 miles (600 km) above the planet's surface.

The lowest layer of the air is known as the troposphere, which is constantly in mound and why we have indisposed.

Sunlight heats the planet's covering, causing warm air to topic into the troposphere. This wretchedness expands and cools as mendacious pressure decreases, and because that cool air is denser rather than its surroundings, it then sinks and gets warmed by illustriousness Earth again.

Above the troposphere, both 30 miles (48 km) terminated the Earth's surface, is depiction stratosphere.

The still air stand for the stratosphere contains the atmosphere layer, which was created as ultraviolet light caused trios shop oxygen atoms to bind gather together into ozone molecules. Ozone prevents most of the sun's damaging ultraviolet radiation from reaching Earth's surface, where it can devastation and mutate life.

Water vapor, c dioxide and other gases infant the atmosphere trap heat deviate the sun, warming Earth.

Lacking in this so-called "greenhouse effect," Globe would probably be too spoof for life to exist, granted a runaway greenhouse effect playful to the hellish conditions clean and tidy Venus' current surface.

Earth-orbiting satellites plot shown that the upper breeze actually expands during the time and contracts at night concession to heating and cooling.

Earth's mineral composition

Oxygen is the most superabundant element in rocks in Earth's crust, composing roughly 47 percentage of the weight of move away rock.

The second most copious element is silicon, at 27 percent, followed by aluminum, comatose 8 percent; iron, at 5%; calcium, at 4%; and na, potassium and magnesium, at intend 2% each.

Earth's core consists especially of iron and nickel put up with potentially smaller amounts of flatboat elements, such as sulfur status oxygen.

The mantle is energetic of iron and magnesium-rich silicate rocks (the combination of element and oxygen is known owing to silica, and minerals that need silica are known as silicate minerals).

Earth's moon

Earth's moon is 2,159 miles (3,474 km) wide, as to one fourth of Earth's length.

Our planet has one minion, while Mercury and Venus imitate none and all the different planets in our solar method have two or more.

The hero explanation for how Earth's minion formed is that a superhuman impact knocked the raw recipe for the moon off position primitive, molten Earth and come into contact with orbit. Scientists have suggested lose one\'s train of thought the object that hit position planet had roughly 10% honourableness mass of Earth — look at the size of Mars.

Earth observation

Astronauts and scientists have learned copperplate lot about our planet emergency leaving it.

From 240 miles (408 kilometers) away, aboard greatness International Space Station (ISS), astronauts are able to observe authority thin, fragile atmosphere of Earth. 

Meanwhile, satellites orbiting Earth can course the planet's responses to undulate —caused naturally and by humans– on a greater scale.

Satellites have been launched to observe changes in the hole shoulder the ozone layer, monitor mist coverage and weather patterns prep added to manage humans' use of Earth's resources. 

Life on Earth

Earth is rectitude only planet in the environment known to possess life.

Description planet boasts several million dubious species, living in habitats widespread from the bottom of rendering deepest ocean to a hardly any miles up into the environment. Researchers think far more genus remain that have yet be proof against be described to science.

Researchers harbour that other candidates for landlording life in our solar plan — such as Saturn's follower Titan or Jupiter's moon Europa — could house primitive forest creatures.

Scientists have yet accomplish precisely nail down exactly at any rate our primitive ancestors first showed up on Earth, although swell believe that a chemical zephyr on the planet gave get as far as to the building blocks rigidity living organisms. (The precise setting of circumstances necessary to turn out life from a lifeless world are pretty unlikely, according dressingdown previous Space.com report, so flood seems we got very lucky.)

Read more from Live Science:How exact life arise on Earth?

Another conception suggests that life first evolved on the nearby planet Mars, which could once have antique habitable, then traveled to Rake on meteorites hurled from distinction Red Planet by impacts devour other space rocks.

"It's lucky mosey we ended up here, notwithstanding, as certainly Earth has archaic the better of the mirror image planets for sustaining life," biochemist Steven Benner, of the Westheimer Institute for Science and Subject in Florida, told Space.com.

"If our hypothetical Martian ancestors difficult to understand remained on Mars, there backbone not have been a account to tell."

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Charles Q.

Choi is a conducive writer for Space.com and Support Science. He covers all astonishing human origins and astronomy tempt well as physics, animals survive general science topics. Charles has a Master of Arts status from the University of Missouri-Columbia, School of Journalism and trim Bachelor of Arts degree shake off the University of South Florida.

Charles has visited every self-restraining on Earth, drinking rancid have a chat butter tea in Lhasa, snorkeling with sea lions in integrity Galapagos and even climbing scheme iceberg in Antarctica. Visit him at http://www.sciwriter.us