Origins of the Solar System

Big bangs, little grains of space dust, a guiding hand or incredible random coincidence; no matter the details or beliefs, the origin of the Solar System is a complex and fascinating topic. The very fact that there are theories at all attest to how far humankind has come in their grasp of their environment, and the questions yet to be answered on how far yet there is to go.

A Look at the Origin of the Solar System

There have been many, many theories about the origin of the Solar System, but it wasn’t until the Eighteenth century that those theories began, in a manner not unlike the topic they cover, to coalesce into a recognisable field of study. With the advent of the Space Age and the ability for scientists to observe and collect data from beyond the reach of our planet’s atmosphere, the various theories concerning the origin of the Solar System were examined and modified, and will be re-examined constantly.

The most commonly held theory regarding the formation for the Solar System was actually first proposed in 1734 by Emanuel Swedenborg, and is called the “nebular hypothesis.” This theory has been expanded and developed quite a bit since then and is often the basis by which other theories are compared. In the nebular hypothesis the age of the Solar System is set at 4.6 billion years, and the catalyst was the collapse of a giant molecular cloud. Recent advances of the theory suggest that multiple supernovas, or exploding stars, created areas of over density that then collapsed together to form the Sun. It is thought that this giant molecular cloud is also responsible for the birth of more stars than our own Sun.

The region of the gas cloud that was to become our Sun was thought to be as large as 20,000 AU (Astronomical Units, or the distance from the Earth to the Sun) but with roughly the same density. As this pre solar nebula collapsed it flattened and became a protoplanetary disk, which is the area of dense gas that surrounds a newly formed star, of about 200 AU. Over about 100 million years the hot protostar in the centre of the protoplanetary achieved hydrostatic equilibrium, when the various pressures on the gas allowed the body to become a star.

From here, a process called accretion took place, where dust particles began to collide and stick together, growing larger and larger, becoming what is called planetesimals, and eventual (over a few million years) becoming planets.

Various other theories are variations on the same theme, and focus on different parts of the origin, such as the formation of the planets as opposed to the entire Solar System. The Capture Theory, for example, examines the possibility that a large body, possibly another star, passed close enough to the Sun to draw off enough matter to create the planets.

The Origin of the Solar System and the Future

Like the origin of the Solar System, the end of the Solar System is a lot of conjecture, but conjecture based on what scientists have been able to learn about the behaviour of the universe. The Solar System as it exists today has an estimate lifespan of one billion years, at which point changes in the Sun and the orbits of various moons will create a new landscape of sorts.

Final Thoughts

One billion years is a long time before the beginning of the end of the Solar System as we know it. During that time humanity’s grasp of science will continue to tighten, and the bits and pieces of Solar System origin theory will be discarded or confirmed along the way.