The cosmos is filled with many mysteries and astronomical phenomena. When we look to the stars it’s easy to wonder what lies beyond our present knowledge and for kids, it’s exactly the same. But the great thing is, thanks to newly developed and highly advanced telescopes, we have learned a ton of interesting facts and information about the planets in our solar system.

This article of fun facts of the planets presents some little-known, yet fascinating tidbits about the planets which comprise our solar system. Use this as a complementary guide to whatever materials on the planets you already have. If you’re looking for Montessori cards for this activity, click here. By the end of the lesson, your little ones will be so full of scientific facts that you may have a future astronaut on your hands.



Imagine you were standing on Mercury, the smallest planet in our solar system, and looking at the sun. It would appear three times bigger and be seven times brighter than if you were standing on Earth. Though Mercury is the closest planet to the sun, it is not the hottest. That honor goes to Venus. Its orbit around the sun is much more elliptical than Earth’s with the distance to the sun ranging between 47 and 70 million kilometers (29 and 43m miles).  

This little planet could easily be confused with our moon. It’s just a little bigger and has a similar cratered grey surface. And being so close to the sun the years go by much faster. It takes just 88 Earth days to complete one orbit, yet has a very slow rotation. One day on Mercury is like 59 Earth days!


The second closest planet to our sun is actually the hottest in our solar system thanks to its very dense atmosphere. It’s so hot on this planet that it can melt lead! Venus is also our closest neighbor and has had many probes sent to test the possibility of colonizing it one day. The atmosphere above the clouds would be an ideal settlement for a floating city. In fact, it is all those clouds that make it look so white when observed by a telescope.

One strange feature of this planet, which is just a bit smaller than the Earth, is its revolution. It is very slow and spins the opposite direction than most other planets in our solar system, with the exception of Uranus.


Home sweet home! Our planet is not only the most beautiful one in the solar system it is also the only one with life on it, that we know of anyway! Who knows what they will discover in the future. We have the 5th largest planet but the largest of the rock and metal based planets, also known as terrestrial. Life here is possible due to multiple factors: the distance to the sun which provides perfect temperatures, the large moon which orbits us, the protection of Jupiter which shields us from countless asteroid strikes, and thanks to the oceans, which allowed algae and plants to grow, we have an atmosphere which contains oxygen, the most important life-permitting element on the planet. Without algae and plants, there would be no photosynthesis and no oxygen and no animals.   


Also known as the red planet, Mars is the 4th planet from the sun and our immediate neighbor in the outer orbits. It’s a cold, desolate planet with extinct volcanos, ice caps, and a very thin atmosphere. Not very life-supporting, but its proximity has sparked the imagination of many story-tellers throughout history with tales of Martians and UFO’s visiting Earth.

Being so close has also meant that it is the most explored planet in the solar system. We have sent many rovers which have investigated the geology, erosion and the possible existence of life. It’s just a bit smaller than Earth and revolves around the sun at an average distance of 228 million kilometers (142m miles). If all goes according to plan, Space X, a private aeronautical company, plans on sending the first manned mission to Mars by 2025. Fingers crossed!   


The 5th farthest planet from the sun, Jupiter, is also the largest in our solar system. It is so massive that if it were a soccer ball then the earth would only be a cherry! Due to its fast revolution, one day takes only about 10 hours, but 1 year lasts 4,333 Earth days. It is the first in a row of four giant gas planets. Like, the sun it’s mostly hydrogen and helium, but those famous stripes around its surface are clouds of water and ammonia. The ‘Eye of Jupiter’ or giant red spot, is actually a tremendous storm which has raged for centuries.

79 known moons orbit Jupiter and it was Galileo who discovered the four largest in the 17th century. Though it is still unknown whether it has a solid core, the inner body of the planet is so dense that electrons are stripped from the hydrogen molecules creating, together with its fast revolution, an extremely powerful magnetic field. This is why it protects the Earth so well from passing meteors, comets and asteroids.


The second largest planet in the solar system and 6th farthest from the sun is Saturn. Without a doubt the most amazing of all our neighboring planets, it is nearly as big as Jupiter. Its radius is about nine times larger than Earth’s compared to eleven times for Jupiter. Like its neighbors, it is a gas giant made of hydrogen and helium and is adorned with gigantic rings of ice and dust.

Equally as spectacular as the planet are its collection of more than 60 moons. They possess some of the most amazing landscapes in the solar system, like the geysers on Enceladus or the methane lakes on Titus. These moons also hold some of the greatest potentials for discovering life as they contain internal oceans flowing beneath crusts of ice.   


Uranus was the first planet discovered using a telescope and appears blue due to methane gas which combined with ice, hydrogen, and helium make up the atmosphere of this gas giant planet. Also known as the ice planet, it is the 3rd largest and 7th farthest from the sun. A quirky characteristic of this planet is that it spins at a nearly 90-degree angle on its axis. This strange revolution makes it look like a wobbly ball when observed with time-lapse video.

Unlike the giant rings of Saturn, Uranus possesses 13 faint rings. The inner ones are darker and bearly visible with the most powerful telescopes, while the outer ones are brighter and easier to spot. It also has many moons, 27 in total. Like Venus, it rotates in the opposite direction as the rest of the planets in our solar system.


The farthest planet from our sun is the windy ice giant Neptune. It is so far from the sun, with a 4.5 billion kilometer average distance (2.8b miles), that during the brightest time of day it would look like twilight here on Earth. The sun looks about 900 times brighter here than on Neptune. It also takes about 165 Earth years to complete one Neptune year, a single orbit around the sun.

Neptune also has 5 rings and 13 known moons making it a very topographically diverse system. The surface is very cold yet scientists believe that an extremely hot ocean flows beneath the freezing clouds. The famous winds can be up to nine times stronger than those on Earth.

Dwarf planets

You may have already heard of Pluto, which was once considered a planet. But it was re-classified as a dwarf planet as it no longer fulfilled the necessary requirements of a real planet. A dwarf planet is simply a large asteroid orbiting our sun in one of the two asteroid belts.

What you might not be familiar with is there are quite a few dwarf planets that accompany Pluto in the Kuiper asteroid belt just beyond Neptune’s orbit. Those dwarf planets include Eris, Makemake, and Haumea. Another asteroid in the main belt between Mars and Jupiter, Ceres, was recently classified as a dwarf planet too. It is the only dwarf planet found within the inner solar system.

Source: NASA



So those are all our wonderful neighbors in the solar system we call home. I think you’ll agree that they are fascinating and deserve more research and exploration. Hopefully, by exciting your kids about space and the wonderful things we can find out there we can inspire them to become future scientists and cosmological explorers.

If you are looking for some ideas for astronomy activities for your kids, have a look at this article. There you will find a treasure trove of books, games, crafts, and videos to satisfy your space fanatic.

12 thoughts on “Fun facts of the planets

  1. Onyx Bearimy Losoya says:

    Definitely bookmarking this page to come back to. Very informative- even if it is just called “fun facts!”

  2. Elisabet Diaz says:

    ¡Gracias por el artículo!
    Creo que están muy bien resumidas las características más importantes de cada planeta

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