This page is intended to give a detailed overview of the Solar System, including the formation of the Sun and planets, discovery and various facts and figures about the many and varied celestial bodies that are influenced by the gravity of the Sun.
With a few exceptions, it took humanity thousands of years to realise that the solar system existed. It was believed the Earth, categorically different from the objects in the aether that revolved around it. It was not until the revolutionary individual Nocholaus Copernicus developed a mathematically predictive model supporting a heliocentric system that the subject began to be taken seriously.
The concept became more widely accepted with the turn of the 17th century and Copernicus's successors, Galileo Galilei, Johannes Kepler and Isaac Newton developing an understanding of physics, which dictated that the Sun was orbited by the planets, and the planets were all governed by the same physical laws as the Earth.
It is thanks to these early Astronomers using earthbound instruments that we know the moons of Jupiter (Galileo 1610) or the elliptical orbits of the planets (Kepler, 1609-1615), or Uranus (Herschel, 1781), Neptune (Galle and Le Verrier, 1846) an of course the controvertial Pluto (Tombaugh, 1930).
The greates leap in our understanding has happened in the last half century with the advent of the space age and space based telescopes, along with the understaning and observation in the parts of the electromagnetic spectrum not visible to the naked eye or ground based instruments.
Below is a shortened version of the nebular hypothesis originally developed by Pierre-Simon Laplace, Emanuel Swedenborg and Immanuel Kant. This idea has fallen in and out of favour several times as new discoveries are made and the model updated.However, with the imaging of young stars with discs of cool matter around them, the model has became widely accepted. For a more detailed version please click here (no link currently).
Approximately 4.6 billion years ago, a star going nova in proximity to a molecular cloud predominately formed from the remenants of red giant stars caused a density differential in the cloud causing it to begin to collapse under it's own gravity. The majority of the collapsing material gathered towards the centre forming a hot dense protostar whilst the remainder formed a flat, rotating protoplanetary disc approximately 200 AU across.
At around 50 million years after the initial formation event, the density of material in the centre of the protostar reached the point where an initial thermonuclear fusion reaction could occur. The reaction rate, temperature and density all competed against eachother trying to blow the star apart or collapse it into a smaller, denser area until hydrostatic equilibrium was reached, where the thermal energy from the fusion countered the force of gravitational collapse. At the point of attaining equilibrium our Sun became a main sequence star.
Whilst over 99% of the mass of this new solar system was squeezing atoms together, the rest was patiently accreting and forming planetessimals around 5 km across, starting as dust that was hundreds of times less dense than the smoke of a cigarette. These particles collided and formed gradually larger bodies, the composition of which varied with their distance from the young Sun. Rocky silicates, relatively stable under high temperatures remained hear the Sun, forming the 4 inner rocky planets, whilst more volatile molecules such as water, methane and hydrogen were blown out by the solar wind out until the energy from the Sun could no longer prevent them from forming liquid vapour of ices, accreting into planetesimals further out eventually forming the gas and ice giant planets. Not all small bodies were incorporated into these planets, some became gravitationally trapped creating moons, or were herded into the asteroid belt. Others were flung by gravitational intteractions with planets, or even by the migration of Jupiter as it moved inwards to it's current orbit, these bodies either left the effect of the Suns gravity, or became TNOs, KBOs or formed the Oort cloud, whilst others became comets or trojans, small bodies that orbit the Sun on highly eccentric, elliptic orbits compared to the galactic plane, some even orbit in the opposite direction to the rest of the planets.