Today we'll take an imaginary space-trip to discover the natural satellites in our Solar System. And what a trip it's going to be, because there are more than 200 natural satellites in our cosmic "neighbourhood".
Which planets have the most natural satellites, and which planets have none? You're about to find out, so get ready for a moon-tastic article.
What are natural satellites?
If you've been following our blog, you already know that there are two types of satellites: natural satellites and artificial satellites. The former are the creation of the Universe; the later are human-made objects that help us "see" into the vastness of space (among many other things).
But back to natural satellites. Natural satellites are cosmic objects that orbit (go around) bigger bodies such as planets and asteroids. Natural satellites can be planets themselves, asteroids, comets, or even moons. That's right, Earth's moon is a natural satellite. And get this: even Earth can be considered a satellite because it orbits the Sun.
The famous astronomer, physicist, and mathematician Galileo Galilei was the one who discovered natural satellites, way back in 1610. While playing with his brand new invention — the telescope — he noticed four objects orbiting around Jupiter. At first, Galileo thought these were stars, but soon realised they were changing their position. "These must be moons!", he thought. And he was right.
Today, we know that there are hundreds of natural satellites In our Solar System, and scientists are discovering more and more. Point your telescope at almost any planet in our System, and you'll see moons of different shapes, various sizes, and umpteen types. Look closer, and you'll discover that natural satellites are worlds in and of themselves, vibrating with the miracles of space.
How many moons does each planet in our Solar System have?
Before we do the count, we must separate between confirmed natural satellites and provisional satellites. Don't worry. It won't be hard; confirmed moons are named after mythical characters, while provisional moons have names that begin with a letter and end with a year.
The difference between the two has to do with how much we know about them. If we have a complete picture, the satellite is "confirmed"; if scientists just stumbled upon it and still need to calculate its orbit, it is "provisional".
Saturn and Jupiter have the most satellites, both confirmed AND provisional. But Saturn takes the lead with a mind-boggling total of 82 satellites (53 confirmed and 29 provisional). In fact, it recently just snatched the lead from Jupiter, which only has 79 satellites (53 confirmed and 26 provisional).
Next on the list is Uranus, with 27 confirmed satellites, and Neptune, with 14 confirmed satellites. Mars prides itself with two natural satellites, while our lovely Earth is thrilled with its one moon.
That leaves Mercury and Jupiter with no satellites. But, hey! These planets have other things going for them (which we'll learn about later).
What about Pluto, you ask? Well, remember that Pluto has been downgraded to the status of "dwarf" planet. However, Pluto does have five satellites, so let's add these to the count.
And let's also add in the natural satellites that belong to Eris and Haumea, the dwarf planets in our Solar System. Eris has 1 moon, and Haumea has 2 moons.
Fun things about natural satellites
If you think that natural satellites are fantastic, you're going to love these fun facts.
The biggest moons in our Solar System are those discovered by Galileo: Io, Europa, Ganymede, and Calisto, all belonging to Jupiter. Oh, and let's not forget Earth's Moon, which is also among the biggest.
With an ocean underneath its icy surface, Jupiter's moon Europa could support life.
On Enceladus, one of Saturn's moons, geysers erupt with water and organic molecules.
Earth's Moon needs 27.3 days to orbit our planet, travelling at an orbital speed of 1km/s.
All natural satellites always face the planets they orbit with the same side. All, except Saturn's moon Hyperion, which is kind of a rebel and spins at random.
Pluto's largest moon is half its size.
Let's wrap it up!
Natural satellites are spectacular, indeed, and we're just beginning to understand them. Stay tuned to learn more.
Oh, and if satellites are your thing, don't forget to check our Nanonaut Programme. We won't dive into the details here, but how does launching your own artificial satellite sound? ;)