Planets in the Solar System

by Mark Tanko


Our sun is made up of mainly two gasses, Hydrogen and Helium. Our  Sun is very large to us but compared to the red giants it is tiny.

Our sun contains about 99.86% of the total mass of our solar system! Over one million earths are known to fit in the sun. The sun is 4.5 billion years old.

The sun is equivalent to 330,060 earths in mass! The sun travels 220 kilometers a second.


A year in Mercury is 88 days, but 1 day is 176 earth days! Mercury was named after the messenger of Roman gods.

Mercury has only 38% of gravity compared to earth, this is also the reason why Mercury has no moons or anything else orbiting it, it has too little gravity to hold anything.

Mercury is the second densest planet, it is made up of heavy metals and rock, which are the main characteristics for terrestrial planets.


Venus is sometimes called earth’s sister planet, because Venus and earth are both almost the same length, earth and venus only have a 638 kilometre difference.

Billions of years ago venus would have possibly had water and a similar climate like earth. Venus is the hottest planet in the solar system, at 462°C. 


This is the only planet we know that can support life.

It is also our home planet. Earth is also the only planet not named after a god, all the other planets are named after a god ( the sun is not a planet ).

Earth is believed to have been once in the middle of the universe.


Mars is known to have the tallest mountain/volcano in the entire solar system!

The volcano is 21,000 kilometres tall and over 600 kilometres wide. Though evidence from volcanic lava flows are so recent it is possible that the volcano is still active.

Mars gets its name from the roman god of war. Though we have had 40 missions to mars, only 18 of them were successful.


Jupiter is well known for its Great Red Spot. The Great Red Spot can fit in 3 earths in it!

Though Jupiter has the shortest day of all planets in the solar system it takes Jupiter 11.8 earth years to make a full orbit around the sun.

Jupiter’s largest moon, Gaymende is also the largest moon in the solar system and it’s bigger than mercury.


 Saturn is the least dense planet in our solar system. One of the first astronomers thought that saturns rings were moons!

Saturn has only been visited 4 times, 3 of does times were flybyes.

Though saturns rings aren’t moons, saturn does have some aditional moons, and 62 of them.

Saturn has the second largest moon in our solar system, Titan.


Uranus is the coldest planet in our solar system. Uranus has 27 moons and 13 rings.

Uranus’s surface is averagely tempature is 197- °C. Only one space craft has been known to flown by Uranus, that space craft was voyager 2.

Uranus makes one trip around the sun every 84 days.


Neptune… one of the smallest ice giants. Neptune is mainly made of Hydrogen and helium and a bit of methane.

Neptune is around 50 000 kilometres. Neptune is also has a very active climate, including storms and others.

The largest storm ever recorded on  neptune was the Great Dark Spot, it was recorded in 1989 and lasted about 5 years.

Neptune is named after the Roman God of the sea.


Pluto… its not even a planet, infact it’s a dwarf planet. The reason it’s a dwarf planet was because pluto is too small to be a planet and pluto also isn’t a moon, making it a dwarf planet, also pluto has 5 moons, and charon is among them.

Pluto is around 2 000 kilometres and its largest moon is charon, which is around 1 000 kilometres. Pluto is also barely larger than the moon. One third of pluto is water!

Pluto has only been visited by 1 space craft, The New Horizons spacecraft, the spacecraft is now on its way to the kuiper belt to take pictures of more distant objects.