# Earth

Well, Earth is the planet we live on. It is the third planet from the Sun of our Solar system which itself is part of the Milky Way galaxy, Universe. So far it is the only known place to have life.

Now behold the grand rendering of the Earth map in ASCII (equirectangular projection):

```
X      v      v      v      v      v      v      v      v      v      v      v      v      v      v      v      X
                        .-,./"">===-_.----..----..      :     -==- 
                     -=""-,><__-;;;<""._         /      :                     -===-
    ___          .=---""""\/ \/ ><."-, "\      /"       :      .--._     ____   __.-""""------""""---.....-----..
> -=_  """""---""           _.-"   \_/   |  .-" /"\     :  _.''     "..""    """                                <
"" _.'ALASKA               {_   ,".__     ""    '"'   _ : (    _/|                                         _  _.. 
  "-._.--"""-._    CANADA    "--"    "\              / \:  ""./ /                                     _--"","/
   ""          \                     _/_            ",_/:_./\_.'                     ASIA            "--.  \/
>               }                   /_\/               \:EUROPE      __  __                           /\|       <
                \            ""=- __.-"              /"":_-. -._ _, /__\ \ (                       .-" ) >-
                 \__   USA      _/                   """:___"   "  ",     ""                   ,-. \ __//
                    |\      __ /                     /"":   ""._..../                          \  "" \_/
>                    \\_  ."  \|      ATLANTIC      /   :          \\   <'\                     |               <
                        \ \_/| -=-      OCEAN       )   :AFRICA     \\_.-" """\                .'
       PACIFIC           "--._\                     \___:            "/        \ .""\_  <^,..-" __
        OCEAN                 \"""-""-.._               :""\         /          "     | _)      \_\INDONESIA
>.............................|..........",.............:...\......./................_\\_....__/\..,__..........<
                              |   SOUTH    \            :   /      |                 "-._\_  \__/  \  ""-_
                               \ AMERICA   /            :  (       }                     """""===-  """""_
                                \_        |             :   \      \                          __.-""._,"",
>                                 \      /              :   /      / |\                     ," AUSTRALIA  \     <
                                  |     |               :   \     /  \/      INDIAN         ";   __        )
                                  |     /               :    \___/            OCEAN           """  ""-._  / 
                                 /     /                :                                               ""   |\
>                                |    /                 :                                               {)   // <
                                 |   |                  :                                                   ""
                                 \_  \                  :
                                   """                  :
>                                     .,                :                                                       <
                       __....___  _/""  \               :          _____   ___.......___......-------...__
--....-----""""----""""         ""      "-..__    __......--"""""""     """                              .;_..... 
                                              """"      : ANTARCTICA
X      ^      ^      ^      ^      ^      ^      ^      ^      ^      ^      ^      ^      ^      ^      ^      X
```

Some numbers about the planet Earth:

- age: 4.54 billion years
- distance from the Sun (nearest, furthest): 147098450 km, 152097597 km, 
- radius (equator, poles): 6378 km, 6356 km
- mass: 5.9 * 10^24 kg
- acceleration by gravity: 9.8 m/s^2
- axial tilt: 23.4 degrees
- length of day: 24 hours
- length of year: 365.25 days
- land vs water area: 148940000 km^2, 361132000 km^2
- average temperature: 15 C

```
     _---"""---_
   .':. ;::.: -./;.
  /;:;:: ':  .-':::\
.|';:'      ';':;:::|.
|::         .:'::;:::|
|::.         ':;:::::|
'|:;           ':;::|'
  \::          .:::/
   ':_        .:_.'
      """----"""
```

*Earth from space*

Earth is the third planet from the Sun and the fifth largest in the Solar System, it has an ellipsoid shape, slightly flattened at the poles. It has formed from space dust nearly 5 billion years ago during the formation of our Solar System. Soon after its formation it was struck by a Mars-sized body, called Theia, which led to the formation of the Moon, Earth's only natural satellite. It's only by curious happenstance that the Moon is currently of the same size in the sky as the Sun, allowing perfect eclipses -- nonetheless the Moon is constantly drifting further away from us and will be visually shrinking. Earth has a hot core (inner one of temperature around 5200 degrees Celsius), an atmosphere (78% nitrogen, 20% oxygen; almost wholly contained below 50 km above sea) and a magnetic field, its surface is mostly (71%) covered by water. Temperatures on the surface stay between -100 C and 60 C, with global average of 15 C. The whole surface consists of 16 large tectonic plates, around 100 km thick. Evidence suggests that life appeared on Earth some 3 and a half billion years ago. Earth's axis of rotation is tilted around 24 degrees, which results in change of seasons as the planet revolves around the Sun. Scientists predict that the Earth will be devoured by the Sun that will expand its radius significantly some 7 and a half billion years from now.

**Coordinates**: to define an exact location *p* on Earth's surface it's most common to use the geographic coordinate system comprising of **latitude and longitude** which function like this: latitude is the angle (in range -90 to 90 degrees) of Earth's center point towards equator and *p* (positive in northern hemisphere, negative in souther hemisphere; alternatively marked as *N* or *S*), longitude (in range -180 to 180 degrees) is the angular distance (positive to the east, negative to the west; alternatively marked as *E* or *W*) of *p* from the prime meridian, by convention chosen to be the line from north pole to south pole through the British Royal Observatory in Greenwich, UK. For example *Hitler Pond, Ohio, USA* is located at [39.554081, -82.990932] or [39deg 33' 14.6916" N, 82deg 59' 27.3552" W], coordinates [90 0] and [-90 0] point to the north and south pole respectively etc. The system suffers from some issues, such as that the two coordinates aren't the same kind of thing (i.e. unlike parallels, meridians are part of great circles and all intersect in the two poles) or that the poles have infinitely many coordinates because on either pole longitude loses a meaning, but in general it's been working well for centuries (for alternative coordinate systems please see the article on sphere). **How many decimal places to use?** It's a little complicated but in general something like this: for precision around 1 meter use 5 fractional decimals (x.abcde), for 10 meter precision 4 decimals, for 100 meter precision 3 decimals and so on. Of course this paragraph wouldn't be complete without some **funny/interesting coordinates** -- giant with giant penis in the UK: [50.8136, -2.475], swastika houses: [40.737, 17.734], another swastika: [32.676, -117.158], penis shaped building: [41.842, -89.486], miniature world map on a lake: [56.5905, 9.6415], recursive island: [62.65138, -97.7876], recursive lake: [62.651, -97.787], dinosaur meteorite impact epicenter: [21.4, -89.51], Nazca lines: [-14.697, -75.14], heart pond: [41.304, -81.902], Dubai artificial islands: [25.0, 54.99], weird pattern for calibrating satellites: [40.45, 93.740], Area 51: [37.227, -115.838], TODO: more.

LOL IM slightly drunk a little bit

## See Also

- Universe
- history
- stereotypes