Kerbin, otherwise known as the world, is the third planet from Kerbol and the only object in the Universe known to kerbals to harbor intelligent life so far. It is the densest planet in the Kerbol system and the largest of the four terrestrial planets ousting Eve by a small margin. Kerbin is well-known among the Kerbals as being home.

Physical Characteristics 

According to radiometric dating and other sources of evidence, it is believed Kerbin formed about 4.54 billion years ago. Kerbin's gravity interacts with other objects in space, such as asteroids, but especially the Mun, Kerbin's only natural satellite. A Kerbin day lasts 6 hours and during one orbit around Kerbol, Kerbin rotates about its axis over 426 times, thus a Kerbin year is about 426 days and 32 minutes long. Kerbin has a slight orbital inclination, producing seasonal variations on the planet's surface. The gravitational interaction between Kerbin and the Mun causes ocean tides, stabilizes the Kerbin's orientation on its axis, and gradually slows its rotation.

Kerbin's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Kerbin's surface is covered with water, mostly by its oceans. The remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Kerbin's polar regions are covered in ice, including the Kantarctic ice sheet and the sea ice of the Karctic ice pack. Kerbin's interior remains active with a solid iron inner core, a liquid outer core that generates the Kerbin's magnetic field, and a convecting mantle that drives plate tectonics.

One of the most notable features on Kerbin is its large impact crater. Scientists have used radiometric dating to trace this impact to just a few million years ago. It does cross-check with ancient kerbal religion, when an ancient civilization of kerbals said that their gods were mad at them, and threw a planet at them.


The atmospheric pressure of Kerbin is around 101.325 kilopascals and has a composition of 78% nitrogen, 21% oxygen, 1% Argon, with trace amounts of water vapor, carbon dioxide, and other gaseous molecules. The biosphere of Kerbin has altered the composition of the atmosphere over billions of years, indirectly forming an ozone layer that protects life on land, by blocking lethal radiation from Kerbol and outer space. Apart from this, the atmosphere is dense enough to protect Kerbin from small meteors that otherwise could destroy entire areas.



Kerbin's climate is perfectly suited to support a variety of little green creatures that inhabit most of its surface. The mean temperature is 288 Kelvin (15 degrees Celsius), well within the range for liquid water to form and pool on the surface.

Most of Kerbin's history has been dominated by long cold ice ages, followed by brief periods of warmth. The last ice age ended around 10,000 years ago, which roughly coincides with the invention of agriculture by ancient kerbals.

Orbit & Rotation

Kerbin orbits Kerbol at the distance of one KAU, close to the inner edge of Kerbol's liquid water habitable zone (HZ). The planet has a very circular orbit and an orbital inclination of 1.578 degrees. This gives the planet very small hemispheric seasons.

The planet rotates once every 5 hours, 59 minutes, and 9 seconds. This makes Kerbin's solar day exactly 6 hours long.


Kerbin formed from a disk of dust and gas that orbited Kerbol 4.6 billion years ago. The planet accumulated mass over the course of 500 million years and suffered a massive impact by a hypothetical Duna-sized body 4.3 billion years ago which resulted in the formation of the Mun.


The Mun is a relatively large, rocky, planet-like natural satellite, with a diameter about one-quarter of Kerbin's. It is the largest moon in the Kerbol System relative to the size of its planet, and although Char is larger relative to the dwarf planet Kel, since they orbit a barycenter outside of Kel, by definition Char and Kel is a binary (dwarf) planet.

The gravitational attraction between Kerbin and the Mun causes tides on Kerbin. The same effect on the Mun has led to its tidal locking: its rotation period is the same as the time it takes to orbit Kerbin. As a result, it always presents the same face to the planet. As the Mun orbits Kerbin, different parts of its face are illuminated by Kerbol, leading to the munar phases; the dark part of the face is separated from the light part by the solar terminator.

The Mun is believed to have been formed from the leftover debris of an ancient planetary collision between Kerbin and a hypothetical Duna-sized body.


Kerbin is one of only three worlds that are/were home to an intelligent, sentient species. The only other bodies that has this title is the Taythe, homeworld of the extinct Ka'vi, possibly Ernes, and the homeworld of The Precursors. Life was seeded on Kerbin 4.28 billion years ago by unknown origins. Major theories range from that life was created by chance in a chemical reaction or panspermia between Kerbin, Duna, and possibly Eve.

Kerbin is known for having many complex ecosystems on the surface, most life residing in the grasslands. Other than small insects, most life on Kerbin is either bipedal or quadrupedal. In the oceans large amounts of fish reside there.


Kerbin biome
  • Ice Caps
  • Northern Ice Shelf
  • Southern Ice Shelf
  • Tundra
  • Highlands
  • Mountains
  • Grasslands
  • Deserts
  • Badlands
  • Shores
  • Water
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