Sol

From Growing Horizons
Sol
False-color image taken in 2010 as seen in ultraviolet light (wavelength of 30.4 nm)
Spectral ClassG2V
Mass M1
Surface Temperature5772 K
Heim-Feynman Limit Distance5.5 AU
Distance to Sol0 ly

Sol is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma,[18][19] with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometers (864,000 miles), or 109 times that of Earth, and its mass is about 330,000 times that of Earth. It accounts for about 99.86% of the total mass of the Solar System. Roughly three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.

The Sun is a G-type main-sequence star (G2V) based on its spectral class. As such, it is informally and not completely accurately referred to as a yellow dwarf (its light is closer to white than yellow). It formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core. It is thought that almost all stars form by this process.

The Sun currently fuses about 600 million tons of hydrogen into helium every second, converting 4 million tons of matter into energy every second as a result. This energy, which can take between 10,000 and 170,000 years to escape from its core, is the source of the Sun's light and heat. When hydrogen fusion in its core has diminished to the point at which the Sun is no longer in hydrostatic equilibrium, its core will undergo a marked increase in density and temperature while its outer layers expand, eventually transforming the Sun into a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable – but not for about five billion years. After this, it will shed its outer layers and become a dense type of cooling star known as a white dwarf, and no longer produce energy by fusion, but still glow and give off heat from its previous fusion.

The enormous effect of the Sun on Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. The synodic rotation of Earth and its orbit around the Sun are the basis of solar calendars, one of which is the predominant calendar in use today.

Earth

Earth
The Blue Marble, the first full-view photograph of the planet, was taken by Apollo 17 astronauts en route to the Moon in 1972
Geophysical Data
System PositionSol
Distance from Primary1 AU
Planet TypeTerrestrial
Natural Satellites1
Day Length23h 56m 4.100s
Surface Gravity9.81 m/s²
Atmosphere
  • 101.325 kPa
  • 78.08% nitrogen (N2; dry air)
  • 20.95% oxygen (O2)
  • ~ 1% water vapor (climate variable)
  • 0.9340% argon
  • 0.0408% carbon dioxide
Mean Temperature14°C
Surface Water71%
Age4.6 billion years
Infrastructure
Nations (2185)
Earth 
184 nations
Moon 
4 nations
Cislunar Space 
13 nations
Demographics (2185)
Humans 
; Earth : 12 billion ; Moon : 650 million
Quetzal 
1.2 million (overall)
Turukal 
453.234 (overall)
Ormiold 
754.931 (overall)

Mars

Mars
Pictured in natural color in 2007
Geophysical Data
System PositionSol
Distance from Primary1.53 AU
Planet TypeArean
Natural Satellites2
Day Length24h 37m 22s
Surface Gravity3.72 m/s²
Atmosphere
  • -0.636kPa
  • 95.97% carbon dioxide
  • 1.93% argon
  • 1.89% nitrogen
  • 0.146% oxygen
Mean Temperature-63.2°C
Age4.6 billion years
Infrastructure
Nations (2185)
  • Mars Senatorial Republic
  • Ares Democratic Republic
  • 12 colonies
Demographics (2185)
Humans 
350 million
Quetzal 
75.231
Turukal 
32.130
Ormiold 
21.540

Asteroid Belt

Various
Geophysical Data
System PositionSol
Distance from Primaryvarious
Planet Typevaries
Natural SatellitesN.A
Day Lengthvaries
Surface Gravityvaries
AtmosphereNone
Surface Water71%
Age4.6 billion years
Infrastructure
Nations (2185)
  • 14 nations
  • 124 colonies
Demographics (2185)
Humans 
1.23 billion
Quetzal 
765.631
Turukal 
243.734
Ormiold 
564.213
Europans 
1.2 million

Jupiter

Jupiter
Full disk view in natural color in April 2014
Geophysical Data
Natural Satellites85
Infrastructure
Nations (2185)
  • 3 nations
  • 3 colonies
Demographics (2185)
Humans 
400 million
Europans 
~2.43 billion (estimated)

Saturn

Saturn
Pictured in natural color approaching equinox, photographed by Cassini in July 2008; the dot in the bottom left corner is Titan
98
Geophysical Data
Infrastructure
Nations (2185)
  • 1 nation
  • 1 colon
Demographics (2185)
Humans 
100 million