How Many Moons Does Each Planet Have?

How Many Moons Does Each Planet Have?

If you have ever wanted to take a break from real life and get some ‘space’, this piece is just the thing for you!

Ever wondered how many moons each planet has and how many our Earth could have other than the one we see every night? Well, we have the answers whether you have the questions or not.

Do The Planets Have More Than One Moon?

Let us restrict our study to the nine planets in our solar system. If we begin questioning how many moons each planet has in the universe, we would have an endless list! One of the many things that make our solar system so unique is the richness of our celestial bodies.

Each of them has its properties and comes in various shapes and sizes. While some are as big as Jupiter, others have rings like Saturn. Hence, it comes as no surprise that each planet has a different number of moons. Almost all our major planets have moons that were born naturally from dust and leftover gas.

While the Earth is known to have one natural satellite, others like Saturn and Jupiter have many moons. To keep things simple, the larger the planet is, the more moons we are likely to find on it. Is it possible for us to travel to these moons and survive in their atmospheres? Keep reading to find out!

Hang On A Second. How Do We Define Moons?

Broadly speaking, a moon is a celestial object in the night sky that revolves around a planet. But even dust particles revolve around planets. Are they moons too? No, let us understand how we can differentiate moons from other objects floating in space.


There are certain aspects to be kept in mind while categorizing an object as a moon or just another object floating in space. To be considered a moon, the following criteria need to be met:

  • Is it following a heliocentric orbit? This means that it must revolve around both the Sun as well as its planet.
  • Is it roughly spherical?
  • Is it smaller than the planet it is revolving around? If it is around the same size as the planet it orbits, then it could just be another planet.
  • Is it big enough to clear a majority of its orbit of debris? It needs to be the dominant celestial body in whatever orbit it is making.

This means that moons need to be bigger than dust particles but smaller than the host planets they belong to. They need to follow orbits around both their host planets and the Sun. They need to have a roughly spherical shape and could have been formed naturally or have been captured by their host planets.

How Many Moons Does Each Planet Have?

To make this palatable, let’s divide the planets into inner planets and outer planets. The inner planets include:

  • Mercury
  • Venus
  • Earth
  • Mars

Namely, the first four planets in the solar system nearest to the Sun. Let us delve deeper into how many moons each planet has.


Mercury is nearest to the Sun which makes it very hot. It is also a very small planet that cannot hold an orbit around itself. If a celestial object tries to revolve around Mercury, it would crash into the planet.

If it manages to get pulled into the Sun’s orbit, it has a chance of crashing into the Sun also. Due to this, Mercury has zero moons.


Venus is the second nearest planet to the Sun. It also has zero moons owing to tidal gravitational forces. This means that any moon existing on its surface would get destroyed.

Since Venus spins counterclockwise, there are some theories that Venus had an escaped moon. Venus then changed its direction to a clockwise rotation and ended up making the moon drift away. Suppose the moon hadn’t drifted away, chances are it crashed into the planet.


We have arrived at our planet and as we know it, we have one moon. Unlike our other planets, the Earth’s moon is simply called the ‘Moon’. This is because it was the first moon to be discovered and at the time, no knowledge of other moons existed.

The story goes that a small planet impacted the Earth. This was about the same size as Mars and made some of the outer material of the Earth launch into space. It resulted in the formation of our Moon.

This also resulted in a distortion of the Earth’s gravitational field. It helped our planet hold on to its moon and prevent it from floating away.


Mars is known to have two moons. Research indicates that they are captured asteroids owing to their irregular shape and carbon-rich composition.

Roman mythology plays a crucial role in the naming of Mars and its moons. Mars had its name derived from the Roman god of war. Its moons are Phobos and Deimos, which mean fear and terror, respectively.

Phobos and Deimos

Phobos revolves around Mars at a rapid eight hours and a distance of 3,700 miles from the planet. This is the closest any moon has orbited around its host planet in the entire solar system.

Considering the strong gravitational force Mars is exerting on Phobos, it might crash into Mars in another fifty years. There are also chances of it crumbling and remaining in orbit.

Deimos revolves around Mars at a little above 30 hours and a distance of about 48 million miles. Contrary to Phobos, it has very low gravity and any ejecta from a meteorite impact might end up escaping into space.

Both of these moons have similar compositions that indicate that they are from the outer asteroid belt. Mars has captured these asteroids and retained them for all these years.

How Many Moons Are Present In The Outer Planets?

This is where the numbers get big! The outer planets include:

  • Jupiter
  • Saturn
  • Uranus
  • Neptune
  • Pluto

They have more natural satellites than the inner planets do due to their presence in the colder section of the solar system. This is the portion where water froze and turned to ice. This gave the planets a rich surrounding disk and the leftover materials became small moons.


They are called the gas giants for a reason. These planets are very large and have strong gravitational pulls that capture passing asteroids. These morph into satellites and irregular moons.

Hang on tight because these numbers are going to shock you!


Jupiter is the largest planet in our solar system and has 79 moons! Out of these, 53 of them have been named and the other 26 are yet to be officially named.

The largest four moons are called the Galilean moons and are named:

  • Europa
  • Io
  • Ganymede
  • Castillo

Did you know that Io is the most colorful and volcanically active moon in our solar system? And that Europa is the one most likely to pose possibilities of life on it? Yes, it has ice on its surface, but there are assumptions of a salty ocean below it. It was kept safe from freezing by the icy layer above and Jupiter’s tides kept it warm.

What about Ganymede? It is the largest moon in our solar system and has a magnetic field of its own. With a diameter of 3,272 miles, it is notably the only moon in the entire solar system that has a magnetic field.

Finally, Castillo has a surface that is filled with craters and is said to be Jupiter’s second largest moon. This massive planet has massive moons, which in a way, is not so unbelievable.


Saturn is known to be a planet with rings. It has 82 moons out of which 53 are named. The other 29 haven’t yet been confirmed and are yet to receive official names.

The smallest moon on Saturn is probably Mima which is about 123 miles and the largest is Titan which is around 1,600 miles. Titan and Enceladus are the most studied ones owing to their uniqueness and depth of research possibilities.

What makes Titan so interesting is that it is the only moon with liquid rivers on its surface. These seas are made of ethane and methane. Water may be buried under its surface which promises hopes of life existing on it.


It is believed that Uranus has 27 moons that have been confirmed and named to date. It is interesting to note how these moons have been named after characters and plays. The moons with some of their names of origin include:

  • Ophelia (a popular character by Shakespeare)
  • Miranda
  • Ariel (Alexander Pope’s poem)
  • Puck (Shakespeare’s infamous character)
  • Cordelia
  • Oberon
  • Belinda (Alexander Pope’s poem)

And much more. At the mention of these names, people immediately think of popular plays, poems, and characters in mythology. This is what makes Uranus and its moons the most interesting objects of study in the solar system.


Neptune has 14 that orbit it. Triton is the coldest moon in our solar system with a retrograde orbit. This means that it orbits Neptune in the opposite direction to the planet’s rotation. It is the most studied moon owing to its reflective surface.

The temperature on Triton is almost -400°F and it was the first Neptunian moon to be discovered back in 1846.


A lot of people don’t consider Pluto to be a part of our solar system. But since we are focusing on how many moons each planet has, we must consider it too.

Pluto has 5 moons that have been discovered and named. Their names include:

  • Charon
  • Kerberos
  • Nix
  • Styx
  • Hydra

The innermost moon is Charon which is also the largest of Pluto’s five moons. This planet lies in the Kuiper belt that is beyond Neptune’s orbit. Despite being a dwarf planet, it is the largest one in the Kuiper belt.

Let’s Make It Simpler

We have learned a lot so far and we might find it hard to remember so many moons that exist near so many planets. To make it simpler for you to consume what has been mentioned so far, take a look at the comprehensive table given below:

Planet Name

Number of Moons



















This gives us a total of 210 moons in our solar system.

Frequently Asked Questions

How Many Moons Are Present In The Entire Universe?

Hypothetically, we have close to one trillion moons. Unfortunately, we lack the technological capacity to quote the exact number of moons in the entire universe. There are a hundred billion stars each in two trillion galaxies. Each star may have a set number of planets that have anywhere between zero to a hundred moons.

Which Moon Is The Smallest In The Solar System?

Mars has two moons out of which Deimos is the smallest moon in our solar system. It is just 7.7 miles in diameter, which is smaller than the majority of moons we have discovered to date.

Does Saturn Have The Maximum Number Of Moons?

Bingo! Saturn has 82 moons which is the largest number of moons any planet has in our universe. All of these moons orbit the rings around the planet.

Summing Up

It is safe to say that our solar system has about 210 moons if we count the total of the nine planets. But if we broaden our horizons to the entire universe, there could be over a trillion moons!


The solar system is incredibly massive and there are planets, stars, moons, and more of varying sizes, properties, and shapes. We cannot begin to fathom the capacity of our solar system with the knowledge we possess.

While some moons are large, others are very small. While some of them were formed naturally from dust and gases, others were asteroids captured by the planet’s gravitational pull. Some pose possibilities of life while others are impossible to survive on even for a minute!

But one thing is for certain. As long as we keep looking and asking the right questions, there is infinite scope to learn in the solar system!

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