THE SOLAR SYSTEM
AND EXPLORING SPACE
Our Solar system includes everything affected by the Sun's gravitational pull. It includes the Sun at its centre, as well as everything orbiting around it: eight planets and numerous other objects, such as moons, asteroids, meteors and comets.
Our solar system was formed 4.6 billion years ago. It was believed that 4.7 billion years ago, gravity pulled a cloud of dust and gas together to form our solar system. The massive concentration of dust and gas created a molecular cloud that would eventually form the Sun. With the birth of a Sun, planets began to form 100 million years later around it.
Our solar system was formed 4.6 billion years ago. It was believed that 4.7 billion years ago, gravity pulled a cloud of dust and gas together to form our solar system. The massive concentration of dust and gas created a molecular cloud that would eventually form the Sun. With the birth of a Sun, planets began to form 100 million years later around it.
Size and Structure of the Solar System
The image below shows the size and structure of our Solar Syatem, for comparison purposes. See how small Earth is compared to Jupiter, Saturn and the Sun.
The furthest object that we can see in our solar system is Sedna, which is 143.73 billion Km away from the Sun. This means that the diametre of the Solar system is 287.46 billion Km.
There are eight planets in our solar system and one sun that each planet orbits around. An orbit is a regular, repeating path that one object takes around another. Therefore, all planets orbit the Sun, but their position varies thanks to their different mass. The Earth takes a year to go around the Sun, but some planets take much longer due to being so far away. Neptune, for instance, takes 165 years to orbit the Sun.
There are eight planets in our solar system and one sun that each planet orbits around. An orbit is a regular, repeating path that one object takes around another. Therefore, all planets orbit the Sun, but their position varies thanks to their different mass. The Earth takes a year to go around the Sun, but some planets take much longer due to being so far away. Neptune, for instance, takes 165 years to orbit the Sun.
Orbit durations
see how they increase depending on how far the planet is!
Mercury - 88 days to go around the Sun
Venus - 224.7 days
Earth - 365 days
Mars - 687 days
Jupiter - 12 years
Saturn - 29.5 years
Uranus - 84 years
Neptune - 164.8 years
see how they increase depending on how far the planet is!
Mercury - 88 days to go around the Sun
Venus - 224.7 days
Earth - 365 days
Mars - 687 days
Jupiter - 12 years
Saturn - 29.5 years
Uranus - 84 years
Neptune - 164.8 years
Scientists found evidence that there may be a very large, ninth planet beyond Neptune, by tracking its gravitational pull -- but no one has spotted it yet!
Before we start checking out our Solar System's planets and seeing their different and unique stats, it's a good idea to talk about some of the terms we might hear.
You know what is temperature, pressure, axis; but do you know what is equinox, aphelion and periphelion? Watch the video below to find out.
You know what is temperature, pressure, axis; but do you know what is equinox, aphelion and periphelion? Watch the video below to find out.
So, Aphelion is the point when a planet is the furthest from the Sun, while Periphelion is the point when a planet is closest from the Sun.
The Planet that Was
Before we hit the eight planets that are, let's take a brief moment to acknowledge the little planet that was - Pluto!
Since 2006, Pluto has lost its planet status. It's been a long time now -- longer than all of you have been alive -- but it's still pretty sad for us older people. It does show, however, that science is always evolving and changing, and as you know more, you can always update the science!
Since 2006, Pluto has lost its planet status. It's been a long time now -- longer than all of you have been alive -- but it's still pretty sad for us older people. It does show, however, that science is always evolving and changing, and as you know more, you can always update the science!
Let's review!
What are the three conditions for a celestial body to be called a planet?
After the discovery of the Kuiper belt, and after noticing that Pluto's gravitational pull was not able to clear an area around it from the small glass objects, it made more sense to consider Pluto not as a planet, but the biggest Kuiper Belt object.
What are the three conditions for a celestial body to be called a planet?
- It must orbit a star (in our cosmic neighborhood, the Sun).
- It must be big enough to have enough gravity to force it into a spherical shape.
- It must be big enough that its gravity has cleared away any other objects of a similar size near its orbit around the Sun.
After the discovery of the Kuiper belt, and after noticing that Pluto's gravitational pull was not able to clear an area around it from the small glass objects, it made more sense to consider Pluto not as a planet, but the biggest Kuiper Belt object.
Birth of the Solar System
How did the Solar System appear? Let's find out! Watch birth of the solar system here!
THE OUTER PLANETS
The OUTER PLANETS of the Solar system are the planets that are farthest from the Sun. The outer planets are all called GAS GIANTS, because although they have rocky or metallic cores, they are mostly made of gassy sludge. Gas giants don't have defined outlines and are much larger than the terrestrial or inner planets.
The gas giant planets are Jupiter, Saturn, Neptune and Uranus.
The gas giant planets are Jupiter, Saturn, Neptune and Uranus.
General Characteristics of Gas Giants
Composition: Primarily composed of Hydrogen and Helium, with small amounts of other gases such as methane, ammonia, and water vapor.
Size: They are much larger than terrestrial planets and have a massive size. Jupiter is the largest planet in our Solar system.
No solid surface: Gas giants do not have a solid surface that one could stand on. They have thick atmospheres that become progressively denser as you move deeper into the planet. We say they have a mettalic core because the pressure is so high in the middle, that Hydrogen behaves like a metal, squished by the pressure.
Weather patterns: These planets have internal heat sources that create intense weather patterns, such as powerful storms and winds that can reach up to several thousand miles per hour.
Strong magnetic fields: Gas giants have strong magnetic fields that are much larger than Earth's.
Rings and moons: Gas giant planets, such as Saturn and Jupiter, often have numerous moons and ring systems that orbit around them.
High density: Despite their large size, gas giants have a relatively high average density, indicating they have a relatively small rock core, and large Hydrogen and Helium atmosphere.
Different colours and patterns: Gas giant planets have different colours and patterns depending on the composition of their atmospheres and the weather patterns tha occur in them.
Life on a gas giant: It is unlikely that life as we know it could exist on a gas giant planet. With nothing to stand on and an atmosphere with intense pressure and temperatures, the species we have on Earth would not survive.
Let's take a closer look at each Gas Giant:
Size: They are much larger than terrestrial planets and have a massive size. Jupiter is the largest planet in our Solar system.
No solid surface: Gas giants do not have a solid surface that one could stand on. They have thick atmospheres that become progressively denser as you move deeper into the planet. We say they have a mettalic core because the pressure is so high in the middle, that Hydrogen behaves like a metal, squished by the pressure.
Weather patterns: These planets have internal heat sources that create intense weather patterns, such as powerful storms and winds that can reach up to several thousand miles per hour.
Strong magnetic fields: Gas giants have strong magnetic fields that are much larger than Earth's.
Rings and moons: Gas giant planets, such as Saturn and Jupiter, often have numerous moons and ring systems that orbit around them.
High density: Despite their large size, gas giants have a relatively high average density, indicating they have a relatively small rock core, and large Hydrogen and Helium atmosphere.
Different colours and patterns: Gas giant planets have different colours and patterns depending on the composition of their atmospheres and the weather patterns tha occur in them.
Life on a gas giant: It is unlikely that life as we know it could exist on a gas giant planet. With nothing to stand on and an atmosphere with intense pressure and temperatures, the species we have on Earth would not survive.
Let's take a closer look at each Gas Giant:
Neptune
- Farthest planet from the Sun
- Bluish-green in colour
- Atmosphere can change rapidly, with powerful wind storms that break the sound barrier
- Has at least 13 moons and many space dust rings
- Neptune is the only planet in our Solar system that we can't see with the naked eye.
- A day in Neptune is pretty short, only 16 hours -- but each year takes 165 Earth years to complete!
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Uranus
- Bluish-green in colour, caused by methane in its atmosphere
- Atmosphere is hydrogen, helium and methane
- Has at least 27 moons
- Probably mostly ice and rock
- It spins in the opposite direction as the Earth
- Uranus is flipped on its side, as if standing on its rings. This position is very, very unusual, and would not have happened normally!
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Saturn
- Second largest planet, with the lowest density
- Mostly hydrogen and helium
- has a complex system of rings, which are made of ice, rock particles and space dust
- Has at least 60 moons (and one of the moons has active volcanoes!)
For a long time, scientists thought Saturn was the only planet with rings. Since the 70s, with better telescopes and tools, it became known that many planets have rings, not just Saturn. In fact, every single one of the giant gas planets -- Jupiter, Saturn, Uranus and Neptune -- have rings. The thing that makes Saturn's rings different is the way in which they were formed... as well as how visible they are. Let's find out more!
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Watch Saturn - The Moon King
Jupiter
- Largest planet in the Solar system
- Made mostly of hydrogen, helium, ammonia, methane, and water vapor
- Has at least 66 moons, including the largest moon in our solar system
- has white, red and brown stripes, which are gas storms. The Great Red Spot (a giant red spot permanently on the surface) is a huge storm.
- Mass: 318 Earths
- Orbital speed: 13.06 km/s
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THE INNER PLANETS
The four planets closest to the Sun are called the INNER PLANETS. All of the Inner planets are TERRESTRIAL PLANETS, which means "earthlike". The terrestrial planets are made of rocks and have iron cores, just like Earth. Many of the inner planets have craters, or holes on their surfaces, caused by rocks smashing into them.
The terrestrial planets in our solar system are Mercury, Venus, Earth and Mars.
The terrestrial planets in our solar system are Mercury, Venus, Earth and Mars.
General Characteristics of Terrestrial Planets
Composition: They are primarily composed of rock and metal and have a solid surface.
Size: They are typically smaller than gas giant plants and have a higher density.
Geology: They have a varied Geology, and can have mountains, valleys, canyons and other landforms.
Different atmospheres: Terrestrial planets have different atmospheres depending on the specific planet, for example Earth has a diverse climate and weather patterns, while Venus has a thick atmosphere that causes a greenhouse effect.
Strong magnetic fields: Some terrestrial planets like Earth have strong magnetic fields that protect the planet from harmful solar radiation.
Different colours and patterns: Terrestrial planets have different colours and patterns depending on the composition of their surfaces and atmospheres.
Closer to the Sun: Terrestrial planets are located in the inner part of the solar system, closer to the sun.
Life on Terrestrial Planets: Life on other terrestrial planets hasn't been discovered. Mars has a dry and cold environment that we are currently searching for life on. Scientists are constantly searching for signs of life on other planets as well, although we have not landed on them. We are looking at life on Venus, as well as other planets and moons in our solar system and beyond.
Let's take a closer look at each Terrestrial Planet:
Size: They are typically smaller than gas giant plants and have a higher density.
Geology: They have a varied Geology, and can have mountains, valleys, canyons and other landforms.
Different atmospheres: Terrestrial planets have different atmospheres depending on the specific planet, for example Earth has a diverse climate and weather patterns, while Venus has a thick atmosphere that causes a greenhouse effect.
Strong magnetic fields: Some terrestrial planets like Earth have strong magnetic fields that protect the planet from harmful solar radiation.
Different colours and patterns: Terrestrial planets have different colours and patterns depending on the composition of their surfaces and atmospheres.
Closer to the Sun: Terrestrial planets are located in the inner part of the solar system, closer to the sun.
Life on Terrestrial Planets: Life on other terrestrial planets hasn't been discovered. Mars has a dry and cold environment that we are currently searching for life on. Scientists are constantly searching for signs of life on other planets as well, although we have not landed on them. We are looking at life on Venus, as well as other planets and moons in our solar system and beyond.
Let's take a closer look at each Terrestrial Planet:
Mars
- Looks red because it contains iron oxide (rust)
- Has ice caps and rift valleys and the largest volcano in the Solar system, Olympus Mons
- Has a thin atmosphere that is mostly Carbon dioxide
- Has huge dust storms and seasons
- Has two small moons, Phobos and Deimos
- Mass: 0.107 Earths
- Orbital speed: 24.07 km/s
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Wow! Water on Mars!!!
But wait... to actually reach it, humans would have to dig 15 to 20 kilometers deep in order to reach it.
How could we go about getting to the water? Talk on your table about this!
But wait... to actually reach it, humans would have to dig 15 to 20 kilometers deep in order to reach it.
How could we go about getting to the water? Talk on your table about this!
Earth
- This old dirt ball that we take for granted
- Only planet known to support life, helped by its unique properties such as liquid water, atmosphere, our magnetic field and an ozone layer
- Has one large moon
- Mass: 1 Earth (ha ha), or 5.972X10^24 kg
- Orbital speed: 29.78 km/s
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So, our amazing Earth has five different layers, with different characteristics as you can see below:
- Troposphere: Where we live! Weather, rain, winds, all of these phenomenon are in this layer. It contains almost all the water molecules and 75% of all of the "air" molecules. The higher you go, the colder it gets.
- Stratosphere: This is the layer right above the Troposphere. It contains most of the Ozone in the atmosphere. This layer gets hotter the highest you go, because of the absorption of UV radiation from the Sun.
- Mesosphere: In this layer, the higher you go, the coldest it gets. Because it is so hot at its lowers area, most of the meteors that enter our atmosphere burn in this layer (and the rest burn off in the Stratosphere!)
- Thermosphere: This layer gets super hot the higer you go, due to the absorption of xrays and UV radiation from the Sun.
- Exosphere: This is the highest you can go and still be on "Earth". This is where the Moon resides.
Earth's Moon
After the Sun, the Moon is the most important celestial body for the Earth. It affects our tides, the light at night, and many have considered that it may even affect human and animal behaviour, perhaps due to melatonin fluctuations. What do we know about the Moon? Let's see a few facts!
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Venus
- Close in size and mass to planet Earth
- Has a dense atmosphere of mostly Carbon Dioxide that collects heat, keeping the planet around 464C
- Mass: 0.815 Earths
- Orbital speed: 35.02 km/s
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Mercury
- Has extreme temperatures (-180C to 430C) because it has no atmosphere
- Looks like Earth's moon, with many cliffs and craters
- Has no moons
- Mass: 0.055 Earths
- Orbital speed: 47 km/s
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The Sun
The Sun was born most likely with a twin. Did you know that stars are born in pairs or litters? I didn't! I find this so interesting. Here is a video about suns, as well as our sun's evil twin, Nemesis!
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Watch Voyage into the Sun
Other objects in the Solar System
Besides planets and moons, there are other objects in our solar system:
Asteroids: Huge chunks of irregularly shaped rocks. They can be found mostly in separate areas of our Solar system (thank goodness!)
We have a disk-like ASTEROID BELT between Mars and Jupiter, as well as two donut-shaped structures called Kuiper Belts. These giant donuts are mostly formed by asteroids. More on Kuiper belts later!
Comets: dirty snowballs made of dust, rock particles, frozen gases, and ice that are orbiting the Sun, usually with enormous orbits. They can take years and years to return. They are sometimes visible to the naked eye when they pass through the inner Solar system because of their long tails -- caused when they are partly vaporized by the Sun (the tail does not follow behind the comet, it always points toward the Sun!)
Oort cloud: A cloud of billions of comets beyond Pluto, named after astronomer Jan Oort, who first proposed the model. More about Oort clouds later!
Meteoroids, Meteors, Meteorites: Meteoroids are small pieces of rock and dust. They become meteors (shooting stars!) when they enter the Earth's atmosphere and burn from all of the atmosphere friction into a bright and hot streak. Most meteors burn out and never reach the Earth; the ones that makes it to Earth without turning into dust are called meteorites, and some people like to collect these.
Here is a recent video of the first time a meteorite's sound was captured!!!
Asteroids: Huge chunks of irregularly shaped rocks. They can be found mostly in separate areas of our Solar system (thank goodness!)
We have a disk-like ASTEROID BELT between Mars and Jupiter, as well as two donut-shaped structures called Kuiper Belts. These giant donuts are mostly formed by asteroids. More on Kuiper belts later!
Comets: dirty snowballs made of dust, rock particles, frozen gases, and ice that are orbiting the Sun, usually with enormous orbits. They can take years and years to return. They are sometimes visible to the naked eye when they pass through the inner Solar system because of their long tails -- caused when they are partly vaporized by the Sun (the tail does not follow behind the comet, it always points toward the Sun!)
Oort cloud: A cloud of billions of comets beyond Pluto, named after astronomer Jan Oort, who first proposed the model. More about Oort clouds later!
Meteoroids, Meteors, Meteorites: Meteoroids are small pieces of rock and dust. They become meteors (shooting stars!) when they enter the Earth's atmosphere and burn from all of the atmosphere friction into a bright and hot streak. Most meteors burn out and never reach the Earth; the ones that makes it to Earth without turning into dust are called meteorites, and some people like to collect these.
Here is a recent video of the first time a meteorite's sound was captured!!!
Your Solar System Project
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For this project, your group will create a model of the solar system, and select one of the planets to highlight.
You must research everything about the planet, and present your model to the class, as well as all you have discovered about your planet. |
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Above, you can see a SCALE MODEL of the Solar system. A scale model is a representation of an object that is usually smaller than the original.
You can see that the sizes are to scale, however the distance between the planets is not; it would be impossible to make a model that would be to scale both in size and distance, due to the size of the Solar system.
You can see that the sizes are to scale, however the distance between the planets is not; it would be impossible to make a model that would be to scale both in size and distance, due to the size of the Solar system.
Your project can be made out of any material you may think of!
Examples of projects include:
Examples of projects include:
- A fruit inspired solar system on a paper base
- A brownie inspired system
- Play dough solar system
- Styrofoam solar system
- Button solar system
- Yarn wrapped solar system
- Knitted solar system
- Plastic lid solar system
- Shoebox solar system with dangling planets
- A mobile
- Coat hanger solar system
You will be presenting this to your class. Make sure you have some facts on each planet to share.
Have fun!
Have fun!
