Did you know? Solar System Edition
- 14th Sep 2016
- Author: Rebecca Howe
Our Solar System is a fascinating place. From the far outer reaches of the Oort Cloud to the Sun itself we’re constantly making new discoveries and exploring uncharted territory. Space missions such as Juno at Jupiter and New Horizons at Pluto and the Kuiper Belt are collecting valuable information to help us answer age old questions such as: ‘Where did we come from?’ and ‘How did our world form?’.
With so much going on, it’s easy to miss some of the more curious facts about our Solar System:
1. The Sun makes up over 99% of the mass of our Solar System
It’s hard to imagine the size of our Sun because it is 93 million miles away, but it actually holds almost all of the size and mass of the Solar System. Jupiter is the next largest, making up around 0.14% of the total mass, while the remaining planets and asteroids make up the rest.
If the Sun was a football, the Earth would be about the size of a small peppercorn and the moon would be smaller than the full stop on a computer keyboard.
2. All of the outer giant planets have rings, not just Saturn
Saturn is known for the beautiful ring system that surrounds it, but did you know that the other three giant planets (Jupiter, Uranus and Neptune) also have rings? These rings are a lot fainter than Saturn’s and can’t be seen with the naked eye but we know they exist because we have sent spacecraft like Voyager 1 and 2 to examine them.
We currently have spacecraft such as Juno and Cassini orbiting around Jupiter and Saturn respectively, collecting data and high resolution images that will help us understand how these giant planets formed and what they’re made of.
3. You only ever see one side of the Moon from Earth
The Moon rotates on its own axis just like the Earth, but unlike the Earth it rotates over the same amount of time that it takes to complete an orbit around the Earth- around 28 days. This means that the same side of the Moon is always facing us, and the other half is always facing away.
This is where the phrase ‘dark side of the Moon’ comes from, but it’s not really true – every part of the Moon receives the same amount of sunlight overall – we just can’t see it (see this in animated form here).
4. Saturn would float in water!
If you had a bath big enough to give Saturn a wash, you would find that the giant planet would actually float instead of sink.
This is because Saturn is less dense than water, meaning that it is actually lighter than the equivalent volume of water and so would float on the surface. That is of course assuming you could find someone willing to make a bath big enough for Saturn!
5. Our Solar System is home to five dwarf planets
Most people know that Pluto is now a dwarf planet, but did you know that there are four other dwarf planets in our Solar System? As the name suggests, dwarf planets are quite simply smaller versions of planets. They are defined by the fact that they haven’t cleared their path around the Sun- their orbits are often blocked by asteroids and other space debris.
Four of these dwarf planets are found at the very edge of our Solar System, and are known as Pluto, Haumea, Eris and Makemake. The fifth dwarf planet is found in the asteroid belt between Earth and Mars and is called Ceres. These five dwarf planets are the only ones to have been classified in this way, but it is possible that there are hundreds more dwarf planets not yet discovered in the Solar System.
The Solar System is our cosmic backyard, but there are still many mysteries to explore. Current and upcoming space missions will continue to help us unravel how the Solar System, the planets and life on Earth first began.
About the Author: Rebecca Howe is a current physics student at the University of Leicester and works as a Science Interpreter at the National Space Centre.
