The Solar System is composed of a single G type star, being orbited by 9 major planets and 11 other dwarf planets. It is on the third planet that complex life began to evolve, and where Humanity as a species was born. The Sol System can only be accessed once the Sol Permit has been granted from the Federal Military.

Sol

Sol or "The Sun" is the star at the center of the Solar System. Its spectral classification is G2 V, meaning it is a hot yellow-white star in the main sequence, currently fusing hydrogen into helium in its core. It is a variable star, its brightness fluctuating by 0.1% over the course of 11 years. Sol isn't as active as other stars in its class, which might have allowed life to arise and flourish on Earth over billions of years.

Mercury

Mercury is the smallest and innermost of the major planets. It completes one orbit in just under 88 days, and is tidally locked into a 3:2 spin-orbit resonance with Sol, rotating 3 times every 2 complete orbits it makes. Its namesake comes from the Roman god Mercurius, messenger of the gods, for this planet moves the faster in Earth's sky than any other planet. Since there is no substantial atmosphere here, Mercury experiences wild temperature shifts between its day and night side, the highest reaching 427°C (800°F), while the lowest can be around -170°C (-274°F).

Venus

Venus is the hottest and second innermost planet in the Solar System. Its surface is obscured from space by a thick layer of sulfuric acid clouds, which are highly reflective, making it the brightest planet seen from Earth. This earning it its name, after "Venus" the Roman goddess of beauty and love. The planet has undergone a runaway greenhouse effect, trapping heat within its carbon dioxide-dominated atmosphere. As a result, temperatures around Venus are about the same, clocking in at a staggering 465°C (870°F), at 93 atm on the surface. Venus rotates backwards compared to other planets, its rotation period being -243 days. This actually makes its rotation period longer than its sidereal orbital period, which is 224 days.

Earth

Earth is the third planet from Sol and the largest of the terrestrial planets. Life began some 4 billion years ago here, evolving from simple self-replicating cells to complex intelligent life. Life on Earth, by photosynthesis, changed the composition of Earth's atmosphere over time, providing substantial amounts of Oxygen, as well as Ozone. This, in tandem with Earth's strong magnetic field, protects its surface from harmful radiation from Sol and other cosmic sources. The first modern humans came about on the continent of Africa some 300,000 years ago, becoming the dominant species on the planet not long after. Humans further developed their societies through farms and towns to major cities and countries, eventually accomplishing space travel where humans first set foot on the surface of another celestial body, the Moon, in 1969.

The Moon

The Moon (or less commonly "Luna") is Earth's sole natural satellite. It formed from a major planetary collision between Earth and a Mars-sized Earth trojan named Theia. This gave Earth its current axial tilt. Over time, the Moon coalesced into a sphere again from the impact and began to cool, its volcanism eventually stopping entirely, the dark lunar mare evidence of where volcanic activity once was. It is tidally locked to Earth, its rotational period being the same as its orbital period. This movement through the sky, causing different phases from Earth's surface, created what are now the months of the year, a month being about the same length as the Moon's orbital period.

The Moon is thought to be a major player in the development of life on Earth, as its gravitational force caused tides on a rapidly-rotating Earth, pulling its liquid oceans back and forth. It also stabilizes Earth's axial tilt, giving the planet consistent seasons. Some life forms evolved to recognize and rely on moonlight at night, such as newly hatched sea turtles, using it to find their way out to the ocean.

Mars

Mars is the fourth planet from Sol, and is the first ever planet to have been successfully terraformed, in 2291. It is the capital of the Federation in the 34th century. In ancient times, this planet was particularly fascinating to humans because of its visually distinct red color in the sky. This gave it the name Mars, the Roman god of war. It has a similar axial tilt to Earth at 25.19°. Humans finally set foot here in the 2070s, and later on in the 2100s uncovered ancient fossils, provinding clear evidence that life once existed there. The iron oxide left over from before terraforming began remains on the surface, still giving the red planet a red hue from space.

Jupiter

Jupiter is the fifth planet from Sol and the largest in the system. It is a Class I Gas Giant and has more mass than all of the other planets combined, doubled. From Earth, it is the third brightest natural object in the night sky after the Moon and Venus. Its namesake is derived from the Roman god Jupiter, king of the gods. Out of all the planets, Jupiter is believed to be the oldest, and is composed of 73.7% Hydrogen and 26.3% Helium (In reality, the composition is ~89% Hydrogen and ~10% Helium, trace elements). It rotates in 9 hours and 55 minutes, and this high speed is what causes the planet's equatorial bulge. The planet's surface cloud layers have an abundance of stripes and storms, but the most notable of which is known as the "Great Red Spot", a massive storm that has persisted since at least the year 1665.

The Galilean Moons

These 4 moons are known as the Galilean Moons after the astronomer who discovered them in either late 1609 or early 1610, Galileo Galilei. These natural satellites were the first objects found to be orbiting a body other than the Earth. Their names come from the Greek lovers of the god Zeus, the equivalent to Jupiter. These moons are special in their own right—the third moon from Jupiter, Ganymede, is the largest moon in the Solar System, its diameter greater than that of Mercury, but not nearly as massive. Europa has a subsurface ocean caused by tidal heating between it and Jupiter. Io, Europa and Ganymede are locked in a 4:2:1 orbital resonance.

Galileo's discovery did not agree with the belief at the time that everything in the sky revolved around the Earth as opposed to the Sun. He also developed a method to determine a person's longitude on Earth based on the predicted timings of eclipses from the moons onto Jupiter. This was actually the precursor to finding that the speed of light is not actually infinite, but does in fact take time. Earth's distance to Jupiter greatly changes over the course of its year, and as a result the time it takes for light to travel from Jupiter to Earth is longer when they are on opposite sides of the Sun than when they are closer.

Saturn

Saturn is the sixth planet from Sol and is the second largest planet in the Sol system. The Class I Gas Giant is famous for its distinctive ring system that has been discernible through telescopes in ancient times. Its name comes from the Roman god of wealth and agriculture. The progenitor for these rings is unknown but it is thought that these rings are the result of a moon that was torn apart by tidal forces.

Moons of Saturn

The Moons of Saturn are fascinating in appearance, as well as how they interact with one another along their orbits. Of its many moons, only six are simulated in the game. The most popular of which being Enceladus and Titan. Titan was the first to be discovered by Christian Huygens in 1655, while Tethys, Rhea, Iapetus and Dione were discovered by Giovanni Domenico Cassini. Enceladus was discovered in 1789 by William Herschel.

Enceladus was the target of many scientific missions since the spacecraft Cassini studied it in close detail beginning in the 2000s. It is covered in fresh ice, as well as cratered regions, which distinctly separate younger and older regions. Major water vapor ejecta are shot from the moon's south pole regions and escape its surface gravity. Eventually these gases begin orbiting Saturn itself, creating Saturn's gaseous E ring.

Titan is significant amongst all the moons in the Sol System, as it is the only one discovered to have a thick atmosphere that is not just tenuous gases. It is mostly composed of Nitrogen with a small percentage of Methane. It is also the second largest natural satellite in the Sol System after Ganymede, and it too has a diameter greater than that of Mercury, but only 40% as massive. It is also the second body ever discovered after the Earth to have stable surface liquids, which are made up of liquid methane.

Iapetus has a visually striking surface, one hemisphere being much brighter than the other. These two hemispheres make the appearance from Earth change in apparent magnitude depending on what side is facing Earth as the moon orbits Saturn. As it is tidally locked, the two hemispheres consistently show up in the same places. This led to them being labeled as the bright hemisphere when the moon was to the west, and the dark hemisphere when the moon was to the east of Saturn. The discoverer, Cassini, correctly identified this being the case in the 1700s.

Uranus

Uranus is the seventh planet from Sol and the largest and least massive of the Ice Giants. Although actually visible with the naked eye in dark skies, ancient astronomers didn't recognize it as a planet, but instead a star because of its slow orbit velocity, not making a noticeable change in position in the sky as much as the classical planets did. The English namesake for this planet and its moons are different than the other planets, as the planet's name Uranus is the Greek god of the sky, whereas the others are named after Roman gods. Uranus was discovered by William Herschel on the 13th of March, 1781. The planet has a significant obliquity, its tilt being 97.7° to its orbit. That means the planet, as well as the rest of the Uranian moon system, orbit near perpendicularly to its orbital plane. The planet also has a ring system, discovered on accident when the rings began to occult the star HD 128598, making the star disappear a few times before Uranus did.

The moons of Uranus are named after the characters in the works of William Shakespeare and Alexander Pope. Only 4 of the 5 major moons are simulated in the game, Miranda being left out. Herschel discovered Titania and Oberon six years after the discovery of Uranus, and in 1851 Ariel and Umbriel were discovered by William Lassell. Miranda was found in 1948 by Gerard Kuiper, and the other moons were discovered either by the flyby of Voyager 2 or other advanced Earth-based telescopes.

Neptune

Neptune is the eighth planet from Sol and the smallest and most massive of the Ice Giants. The planet's namesake comes from Neptune, the Roman god of the sea. Unlike the planets inferior to it, Neptune is not visible to the naked eye and requires a telescope to see it. It is the first of two planets, besides Persephone, to be found using mathematical prediction instead of direct observation. It was found that the observed orbit of Uranus was not following the mathematically calculated orbit, leading Alexis Bouvard to hypothesize that there must be another planet beyond Uranus perturbing it. Urbain Le Verrier calculated where this hypothetical planet might be, and was eventually found within a degree of where Le Verrier predicted it was by Johann Galle. The planet has a very faint ring system, the first of which was discovered in 1968 by Edward Guinan.

Triton

The only simulated moon of Neptune in the game, Triton is a peculiar moon in the Sol System, as it orbits Neptune in retrograde, and is inclined 129° to the ecliptic. And yet, its eccentricity is 0.000016. It is thought to be a captured dwarf planet from the nearby Kuiper Belt. It is the seventh largest moon in the Sol System. For some reason, the body is permit locked and no ships are currently permitted to land there.

Dwarf Planets

In Elite: Dangerous, there are 11 known dwarf planets in the game, but in reality there are plenty more, some not yet discovered.

Pluto and Charon make up a double dwarf planet system in the Kuiper Belt. It was discovered by Clyde W. Tombaugh on February 18, 1930. At the time, astronomers insisted that Uranus' perturbed orbit could not be explained just by Neptune, so they kept searching for the so-called "Planet X". Tombaugh was using a blink comparator to search for small movements in certain night sky pictures when he found it.

In 2006, the International Astronomical Union declared an official definition for a planet, that the object must orbit the Sun, rounded itself into hydrostatic equilibrium, and cleared the neighborhood around its orbit. The last of the three it did not do, and was therefore demoted to dwarf planet. The celestial body would not be visited until July of 2015, when the New Horizons spacecraft did a flyby, taking high-resolution pictures of Pluto and Charon.

The Pluto-Charon barycentre is in a 2:3 orbital resonance with Neptune. In fact, when viewing the entire solar system from above, Pluto's orbit appears to overtake Neptune's, being closer to the Sun than it. However, Pluto's orbit is inclined as such that the orbital path takes it 8 AU above Neptune's.

Persephone

Persephone is a dark and icy body nearly 10 times the mass of the Earth on a very long orbit around the Sun, taking 20,000 years to complete one orbit. It was first hypothesized to exist from apparent perturbations in the eccentric orbits of very distant Kuiper Belt objects. Throughout its search it was tagged as "Planet Nine". Astronomers correctly predicted that something was shepherding these bodies into peculiar orbits, for example the large perihelion of Sedna. It also explained why objects in near-perpendicular orbits have big semi-major axes. This is the second planet wherein its existence was discovered by orbital perturbation.

(Disclaimer: As of right now, no such planet has been found in the outer solar system yet. It continues to be an active area of research, and there is no confirmation that the orbits of extreme parabolic orbiting bodies are being shepherded by a massive force.)