A Guide To The Outer Solar System

A lot of people go about their daily life on a routine; home to work, work to home, home to the market, an occasional trip here and there. They may spend years in a neighbourhood and never really get to know it. As humans we've spent quite a lot of time in the Solar System, and its only relatively recently that we've been able to explore it at all. Since then, however, we have steadily been building a guide to the Outer Solar System.

A Guide To The Outer Solar System

The first order of business is to define what exactly we mean by the 'outer solar system'. Some consider the outer solar system as starting with the asteroid belt, the region of space roughly placed between Mars and Jupiter filled with rocky objects called asteroids. In fact the rocky planets are called 'Inner' and the gas giants 'Outer' but for purposes of this article outer solar system refers to the Trans-Neptunian region. This is the region of space beyond Neptune and ranging out to the end of the Solar System itself. While mostly unexplored we still have a general sense of what is out there, under the influence (however small at the edges) of our sun.

Discovering The Kuiper Belt In The Solar System

The Kuiper Belt is the first region one would encounter when travelling past Neptune. This is a giant ring of debris much like the asteroid belt, comprised primarily of rocky, icy objects ranging in size from dust particles to dwarf planets; including the famous Pluto, once considered the ninth planet of the solar system but downgraded after a 2006 definition of what makes a planet, a planet.

The Kuiper Belt is pronounced like 'viper' and is sometimes called the outer belt, as opposed to the 'main belt' that is the asteroid belt. The entire Kuiper Belt, a region of space that starts about 30 Astronomic Units (AU) from the sun and ends at about 50 AU, has less than a fiftieth of the mass of planet Earth.

The Scattered Disc Of The Solar System

Next up is the Scattered Disc, a region of space that overlaps the Kuiper Belt but goes much further out than 50 AU. It is thought that the majority of short term comets originate in the Scattered Disc region of our solar system, which is filled with Scattered Disk Objects (SDOs). Some astronomers do not recognize the Scattered Disk as a separate region, claiming it to be part of the Kuiper Belt itself.

Where Does the Solar System End?

There are two forces that act on the objects in the solar system; the gravitational pull of the sun, and the solar wind. The Heliosphere is the area affected by the Sun's gravity, the edge of which is called the Heliopause. The exact details of what lies beyond it are a much unknown factor, but it is commonly considered that the Heliopause is the end of the Solar System and the beginning of interstellar space. Beyond the Heliosphere is the Oort cloud, a hypothetical region of space filled with trillions of objects where long period comets come from. Some consider the Oort Cloud to be part of the Solar System, but technically outside and surrounding the solar system.