The Solar System

The Solar System consists of the Sun and the planets and comets bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago.

The Sun makes up 99.86% of the total mass of the solar system.

The distances within the solar system are extremely large, so that it is very difficult to show a realistic diagram of the solar system.

One way of picturing it would be to build an imaginary model of the solar system as follows:[ the reason why it has to be imaginary will become clear quite soon!]
OK let's start: Imagine we are at the MCG (Melbourne Cricket Ground) and a small model of the sun is placed at the centre. Let's make the model of the sun 1cm in diameter (a bit smaller than the size of a 5 cent piece).

The Earth would then be about 1 meter away from the Sun and be very small, and the size of our model of our planet Earth would be smaller than the full stop at the end of this sentence.

Between the Earth and the Sun, would be Mercury about 40 cm from the Sun ( and virtually too small to see) and Venus would be about 60cm from the Sun (and about as small as the Earth).

Mars would be 1.6 meters out from the Sun.

Then there would be the asteroid belt, a sprinkling of dust forming a circle at about 3 meters from the Sun at the center.

Jupiter would be 6 meters away from the Sun and compared to the 1 cm diameter sun, Jupiter would be about 1mm in diameter (about the size of the head of a pin).

Saturn would be 10 meters from the Sun, and Uranus would be about 30 meters away from the Sun.

Neptune would be 45 meters from the Sun and Pluto would be 50 meters from the Sun.

So the limits of the edge of the solar system would be the boundary line. Given the smallness of the Sun and the planets in this model, most of the solar system is nearly empty space.

Now still using this model, how far out from the center of the MCG would the next nearest star be?

Using our imaginary model, the nearest star, Proxima Centauri (4.2 light years away) would have to be 265 km away from the center of the MCG. If we took it as being in a northery direction, it would be in NSW!

Alpha Centuri, would be 275 km from the Sun.

If we were to imagine using this model to also include where the centre of the milky way galaxy is. Then it would be 1.64 million km away from the center of the MCG!