Scale of the Solar System

The solar system is made up of the Sun, eight planets, dwarf planets, moons, asteroids, and comets.
It’s important to understand the scale of the solar system due to the vast distances involved.
The Sun, at the centre of the solar system, accounts for more than 99% of the system’s mass.
Planets move around the Sun in paths called orbits.
The size of each planet’s orbit (its distance from the Sun) increases with the planet’s relative position in the solar system.

Distance in the Solar System

The measurement unit often used when talking about the solar system is the Astronomical Unit (AU).
One AU is the average distance between the Earth and the Sun, approximately 150 million kilometres.
The measurement is used to give an idea of the relative distances in the vastness of space.
For example, Mars is about 1.5 AU from the Sun, indicating it is approximately 1.5 times further from the Sun than Earth.

Not only are the distances in the solar system immense, the planetary bodies themselves are also of significant size.
The gas giants, Jupiter and Saturn, are more than 10 times the diameter of Earth.
Earth’s diameter is in turn about four times that of the Moon.
This reveals the considerable diversity in sizes of the celestial bodies in our solar system.

Understanding the scale of the solar system has been crucial for the planning and execution of space missions by various space agencies.
For instance, the time it takes for a spacecraft to reach another planet depends on the distance and the spacecraft’s speed.
Voyager 2 took about 12 years to reach Neptune, conveying the colossal distances involved in space travel.