The Planets & Space Science

The planets in our solar system can be a very interesting thing to study. Space study engages our minds because we can imagine being an astronaut and heading off in a space ship to explore new worlds. Even if we never get to leave Earth and go to the other planets there is still a lot of things that we can discover. Rocky planets versus gas giants, whether or not there is water on a planet and could we ever live there are just a few of the questions that we might want the answers to. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto are the names of our planets. What exciting information can we find?


Mercury is the planet that is the closest to the sun. It is a rocky planet just like Earth but it is not as big. Mercury is different from some of the other planets because it has no moons. If you look in the sky you can sometimes see Mercury without a telescope. Mercury has many craters and looks similar to our moon. One day on Mercury equals 58 ½ Earth days because Mercury rotates or spins very slowly due to how close it is to the Sun. 


Venus is the second planet to the Sun. It is quite similar to Earth in many ways. Venus is sometimes called Earth’s “Sister Planet” because they are so alike. One way the two planets are different is their temperature. The average temperature on Venus is about 400 degrees Celsius every day. The high temperature is because of the large amount of carbon dioxide in the atmosphere. CO2 is heavy and forms a layer over the planet that holds the heat in.


Earth, the planet that we live on is the third from the Sun. At this time it is the only planet that scientists are certain can support life. Earth is a small rocky planet, sometimes called a terrestrial planet. The Earth is considered to be a young planet and is still changing. Erosion and earthquakes are continually changing how the surface of the Earth looks. Earth is the only planet that has a combination of water, weather, seasons and an atmosphere. It is this mixture that makes Earth able to sustain life.


Mars, the Red Planet, is the fourth planet from the Sun. Mars is a cold planet and has ice caps at both ends that never melt. The ice caps are frozen carbon dioxide. You may know this substance as dry ice. The surface of Mars is very much like Earth with volcanoes, mountains and canyons but liquid water does not seem to exist on this planet. Scientists study Mars closely because it has so many similarities to Earth. The weather on Mars is best known for long lasting dust storms and very high winds.

  • Journey to Mars
  • Kids: Mission to Mars
  • MarsQuest


Jupiter is a planet known as a gas giant. It is the fifth planet from the Sun and if you added all of the other planets together Jupiter would be more than twice the size. If Jupiter were hollow it would take 1000 Earths to fill it up. There is a storm on Jupiter that is called the Big Red Spot and it has been going on for hundreds of years. It can be easy to see Jupiter in the sky although people often think it is just a bright star. With a telescope you can even see some of Jupiter’s moons and maybe even its dark rings.

  • Jupiter
  • Exploring the Planets Jupiter
  • Jupiters Relative Size


Saturn is the sixth planet from the Sun and the only planet that is bigger than Saturn is Jupiter. Saturn is best known for the rings that surround this planet. Unlike Jupiter’s dark rings, Saturn has bright rings. They may look like a solid ring but a close inspection would show that the rings are made of many particles held together by gravity. Saturn is another gas giant and is composed of hydrogen and helium. This bright, ringed planet has eighteen moons that have been discovered. No other planet has that many and there may be even more that scientists haven’t even found yet.


Uranus is planet number seven from the sun. When viewed through a telescope Uranus looks blue. This planet is also a gas giant and the gas that it is made of is called methane. While many of the planets in our solar system have been visited by space craft only one of these, Voyager 2, has ever gone to Uranus. Uranus and Neptune are very close in size but Uranus is much lighter in weight.


Neptune is the last of the gas giants and is the eighth planet from the Sun. It is blue, like Uranus, because of the methane on the planet. Neptune has extremely high winds. They can blow as fast as 2000 km/hour. It takes 165 years (Earth time) for Neptune to orbit the Sun. Like Uranus, only Voyager 2 has ever visited Neptune. The information from that visit combined with photos from the Hubble Telescope are helping us to understand this planet.


Pluto, known as the smallest planet in our solar system, is not even considered a planet anymore. Its new classification is that of dwarf planet. Pluto is so small that some of our solar systems moons are bigger than it is. Pluto is a rocky planet that has never been explored by a space craft from Earth. Pluto is the only planet that can change its place in the lineup. Because the orbit of Pluto does not keep a perfect shape the planet will sometimes move in front of Neptune and become the eighth planet instead of number nine.

Additional resources:

  • Dialogue 4 Kids: Astronomy: a glossary of space, astronomy and planetary terms and their definitions.
  • Amazing Space: a collection of amazing images from the Hubble telescope.
  • Astronomy, Our Place In Space: games, stories and activities to help kids learn about astronomy and the planets in a fun and interactive way.
  • 365 Days of Astronomy: a collection of information to assist parents in getting their children excited about astronomy.
  • The Size and Distance of the Planets: a fun activity guide to help kids understand the concept of relative size regarding the planets in our solar system.

Astronomy for kids:

  • Cool Cosmos: a place where children are encouraged to ask questions and seek answers in a language that they can understand.
  • Eyes On The Sky; Feet On The Ground: A collection of hands on fun and interesting astronomy activities for kids.
  • Astronomy: a well-developed list of sub topics and links to all sorts of astronomy topics.
  • Windows to the Universe: A comprehensive guide to all things that make up our universe including: planets, solar systems, comets, asteroids and stars.
  • Space The Final Frontier: a page full of experiments that relate to space. These experiments are designed for elementary age children.
  • Messenger: a site devoted to Mercury with many online, interactive activities for students
  • How the Human Body Changes in Space: what happens to an astronauts body as they spend time in space? Is it difficult? Does their body change to make it easier.
  • The Universe: Your Cosmic Address: a fun way for kids to learn just how big the universe is and how small a part of it Earth makes up.
  • Massive Things: Galaxies, Dark Matter, Stars and Black Holes: An in depth look at some of the largest things that make up out universe as well as some theories on how they came to be.