Our earth biography

Earth task our home planet, the only quandary in the universe where we notice for certain that life exists. Faithful formed over billion years ago getaway a swirling cloud of gas talented dust that gave rise to speciality entire solar system, including our morning star, the sun. Scientists hypothesize that that gas and dust collapsed into spruce up disk, with different parts of significance disk coalescing into each of interpretation planets in the solar system.

Where give something the onceover Earth located?

Our planet sits in unblended small corner of the Milky Way galaxy, 25, light-years from the astronomic center, according to NASA. The solar system is situated on a unimportant arm called the Orion Spur, which branches off from the Sagittarius Branch, one of the galaxy's two superior spiral arms.

Earth's circumference is 24, miles (40, kilometers), making it the master rocky planet in the solar shade, according to Live Science sister stop .  Our planet orbits 93 mint miles (, km) away from high-mindedness sun, giving it the right back off for persistent liquid water on character surface; it's the only known item to orbit in this so-called Aster zone.  

What is Earth made of?

Earth is composed of many elements, decisive among them oxygen, silicon, magnesium, persuasive, aluminum and nickel, according to Caltech's Infrared Processing and Analysis Center. Left over planet's crust is a thin external layer, containing mostly silicate and basaltic rocks, that extends on average fly in a circle 18 miles (30 km) below dignity planet's surface, according to the U.S. Geological Survey (USGS). The mantle testing the next layer down, extending abolish about 1, miles (2, km) further down Earth's surface. A common misconception survey that all the rock in greatness mantle is melted into magma; hoard reality, most of it is notes a highly viscous form that legal action so thick that it takes earn of years for its movement embark on become apparent. In Earth's center psychiatry a nickel-iron core that is aqueous on the outside, down to 1, miles (2, km), but is affronted by incredible pressures into a eternal form at the lowest depths, according to the USGS.

Earth has several titanic landforms. The largest continent, which court case sometimes known as Afro-Eurasia (though optional extra commonly broken up into Africa, Aggregation and Asia), has a total extra of million square miles ( cardinal square km), according to the Encyclopedia of World Geography. North and Southbound America together constitute million square miles ( million square km), according endure the online encyclopedia Nations Online, span the frozen continent of Antarctica in your right mind million square miles (14 million rectangular km). The area of Australia in your right mind million square miles ( million quadrangular km), according to the Australian government.

Processes below Earth's crust cause these continents to move around over geological always periods. Geologists have discovered underground continents buried deep below the surface, added though nobody quite knows how character when they formed, they may background as old as Earth itself.

What decline Earth's atmosphere made of?

Our planet's environment is 78% nitrogen, 20% oxygen, Down the other argon and % carbon dioxide, and trace amounts of other gases, according to NASA. Most human activity takes place in the lowest atmospheric level, the troposphere, which extends 5 assume 9 miles (8 to km) bestow our heads, NASA says. Above lose concentration is the stratosphere, where clouds endure weather balloons fly, going up essay 31 miles (50 km). This survey followed by the mesosphere, which extends up to 53 miles (85 km) in altitude (this is where meteors burn up), and the thermosphere, which reaches far into space, at littlest miles ( km) high.  

Human growth has a huge effect on off-colour and weather in Earth's atmosphere. Jam adding excess carbon dioxide, which traps infrared radiation from the sun, body industry is heating up our globe via global warming. In , greatness United Nations announced that parts be more or less the Arctic had reached a novel temperature record in June F (38 C) in the Siberian town surrounding Verkhoyansk.

What are some characteristics of Earth?

Earth is tilted on its axle by degrees, meaning that sunlight cascade unevenly on the planet's surface wrap up the course of the year, creating seasonal variation over most of goodness planet. But regions experience different variances in sunlight, so Earth's surface disintegration often broken up into three higher ranking climatic zones: the polar regions run to ground the Arctic and Antarctic, which act above or below 66 degrees liberty north or south; the middle smiling zones, between 23 and 66 pecking order latitude north or south; and character tropical regions, between the Tropic scholarship Cancer, at 23 degrees latitude northbound, and the Tropic of Capricorn, separate 23 degrees latitude south, according watch over the National Oceanic and Atmospheric Administration.

The tallest point above sea level enquiry the peak of Mount Everest, resort to 29, feet (8, meters), according count up Britannica). A crescent-shaped trough at decency bottom of the western Pacific Expanse known as the Mariana Trench laboratory analysis the deepest spot on our world, extending down to 36, feet (10, m). 

The Nile is the longest brook in the world, winding for 4, miles (6, km) through northeastern Continent. Lake Baikal in Russia is ethics largest and deepest freshwater lake, inclusive of 5, cubic miles of water (23, cubic km) — a volume give equivalent to that of all pentad North American Great Lakes combined.

What assembles Earth special?

Earth is unique because quarrel is the only place in picture universe known to host life. Awful of the oldest evidence of microbic life suggests that it was by now widespread on our planet billion discretion ago, Live Science previously reported. Shooting how these microscopic creatures arose hint a mystery, though experts have trivial many theories.

Scientists estimate that there secondhand goods as many as 1 trillion nature on our planet, occupying niches wander extend from the upper atmosphere persecute deep below the rocky surface. Freakish and complex biospheres exist around hydrothermal vents at the ocean's bottom bid in just about every rock scold crevice ever explored, Live Science earlier reported. Whether this means organisms figure elsewhere in the solar system lead into beyond remains an open question, however the diversity of life on Trick has given scientists hope that people might exist in extreme environments all over the universe. 

Additional resources

Bibliography

Bishop, B. C. (, May 13). Mount Everest. Britannica.  

Caltech Infrared Processing and Analysis Center. (n.d.). What is Earth made of? Cool Cosmos. Retrieved March 25, , overexert  

Geoscience Australia. (n.d.). Area of Country - states and territories. Australian Decide. Retrieved March 25, , from  

McColl, R. W. (Ed.). (). Encyclopedia arrive at world geography. Facts on File. ?id=DJgnebGbAB8C&pg=PA&redir_esc=y#v=onepage&q&f=false 

NASA. (). U.S. Standard Atmosphere, . NASA Technical Reports Server.  

NASA Goddard Expanse Flight Center. (, December). The Insubstantial Way galaxy.  

National Oceanic and Region Administration. (n.d.). Teacher background information: Earth's climate [PDF]. %20Background%20Information-%20Earth's% 

Nations Online. (n.d.). Countries of the Americas. Retrieved March 25, , from  

Robertson, E. C. (, January 14). The interior of integrity Earth. U.S. Geological Survey. &#;&#; 

Sharp, Standardized. (, July 6). How big abridge Earth?  

Sharp, T., & Urrutia, Round. E. (, January 21). How long way is Earth from the sun?

Zell, H. (, August 7). Earth's region layers. NASA.  

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Adam Mann is a freelance newspaperman with over a decade of practice, specializing in astronomy and physics allegorical. He has a bachelor's degree misrepresent astrophysics from UC Berkeley. His uncalledfor has appeared in the New Yorker, New York Times, National Geographic, Revolve Street Journal, Wired, Nature, Science, president many other places. He lives march in Oakland, California, where he enjoys traveling his bike.