Emilia Hawkins
Unit 16: Astronomy and Space Science
A: Understand the fundamental aspects of the Solar System.
Section 1 – Components of the Inner and Outer Solar System
Known planets and their composition (rocky, gaseous and dwarf planets)
The planets in the solar system can be separated into two groups based on the composition and
distance from the sun. All the inner planets are small, have rocky, solid surfaces and either don’t
have a moon or have a small number of them. They are made up of a core, mantle and crust and
have a hard rocky surface. The outer planets are large and don’t have solid surfaces., They are
mostly made up of gas and all four have rings that spin around them. In comparison to the inner
planets, those found in the outer reaches of the solar system have considerably more moons
orbiting them. All the planets orbit the sun in and elliptical manner.
Mercury is the closest planet to the sun and has temperatures ranging from 400 oC to -180oC. It’s one
of the smallest planets in the solar system as it only has a diameter of 4,878km. It takes 88 days to
orbit the sun and 59 days to turn on its axis which is tilted at a 0.1 o. Mercury is 57,900,000km from
the sun with a mass of 3.30x1023 kg. It’s covered in craters, similar to the moon, due to meteorites
crashing into its surface. Its atmosphere is made of sodium and helium and it doesn’t have a moon.
Venus is the second closest planet to the sun and is the only planet in the solar system to rotate
clockwise. It is 108,160,000km from the sun, has a diameter of 12,104km and has a mass of
4.87x1024 kg. It takes 225 days to orbit the sun and 243 days to turn on its axis which is at an angle of
177o. Venus’s surface is covered in poisonous clouds containing sulfuric acid and its atmosphere
contains carbon dioxide and nitrogen. The atmosphere is so thick heat cannot escape in to space
meaning temperatures can reach up to 480 oC. Between 200 and 600 million years ago thousands of
volcanic eruptions covered its surface in lava meaning that difficult to find about its history as the
surface is relatively new in planetary terms.
Earth is the third planet from the sun and is the only planet in the solar system able to sustain life. It
is 149,600,000km from the sun, has a diameter of 12,756km and a mass of 5.97x10 24 kg. It takes 365
days to orbit the sun and takes 23 hours and 56 minutes to turn on its axis which is at a 23 o angle,
The atmosphere is mostly made up of Nitrogen, Oxygen and ozone molecules that absorb ultraviolet
light from the sun to prevent it from reaching earth. Earth only has one moon which that orbits the
earth every 27 days.
Mars is the fourth planet from the sun and is the last of the inner planets. It is 227,936,640km from
the sun, has a diameter of 6,794km and a mass of 6.42x10 23 kg. It takes 24 hours and 37 minutes to
spin on its axis which is at 25o and 687 days to orbit the sun. Mars has two moons, called Phobos and
Deimos, that are both irregularly shaped and take 8 and 30 hours to complete an orbit of the planet.
It’s atmosphere is made mostly of carbon dioxide and argon and has an average temperature of -
63oC. The surface of mars is covered in a layer of iron oxide and craters formed by ancient
meteorites. Mars was also once volcanically active and has the solar system’s largest volcano, which
is 27 kilometres high.
Jupiter is the first of the outer planets and the largest planet in our solar system. It is 778,369,000km
from the sun, with a diameter of 142,984km and a mass of 1.898x10 27 kg. Jupiter takes 9 hours and
55 minutes to spin on its axis which is at 3o and it takes 11 years to orbit the sun. It is made mostly of
, Emilia Hawkins
hydrogen and helium with a very small solid or liquid centre, where hydrogen atoms break down to
form a metallic liquid due to the high amounts of pressure. Jupiter has 79 moons, some of which are
larger than other planets in the solar system.
Saturn is the second of the outer planets. It is also made mostly of hydrogen and helium with a liquid
core but has huge rings surrounding it that can be seen using telescopes. Saturn takes 29 years to
orbit the sun but only 10 hours and 33 minutes to rotate on its axis which is at 27 o. It has a mass of
5.68x1026 kg, is 1,427,034,000 km away from the sun and has 82 moons. The rings of Saturn have a
width of over 270,000 kilometres and are made up of rocks and ice. It is believed that the rings were
formed when something collided with the moons orbiting Saturn, and the rock and ice spread out to
orbit Saturn.
Uranus is the third of the outer planets. It is made up of methane, hydrogen and helium with a small
rocky core that could be surrounded by water. It is 2,870,658,186km from the sun, has a diameter of
51,118km and a mass of 8.68x1025kg. It takes 84 years for Uranus to orbit the sun and 17 hours to
rotate on its axis which is at 98o. The planet was first discovered in 1781 and has 27 moons. Uranus is
the only planet to be tilted on its side, where the equator is nearly at a right angle to its orbit.
Neptune is the fourth and final outer planet. It is also made of hydrogen and helium along with
methane, which gives it its blue colour. It is 4,496,976,000 km from the sun, has a diameter of
49,532 km and a mass of 1.02x1026kg. Neptune has the strongest winds in the solar system as the
average speed is over 1,100 kilometres per hour, but can reach speeds of up to 2,000 kilometres per
hour. It takes Neptune 165 years to orbit the sun and 16 hours to rotate on its axis which is at 30 o. It
has 14 moons. Because it is the furthest planet from the sun, it takes the longest to orbit as it has
the furthest distance to travel and is moving at the slowest speed due to the sun’s weaker pull of
gravity.
There are 5 main dwarf planets in our solar system, four of which are located in the beyond Neptune
and one in the asteroid belt between Mars and Jupiter. Dwarf planets don’t have clear orbits and the
path they take is populated by other objects. The atmosphere and composition of these dwarf
planets is unknown, but is thought to contain nitrogen. Dwarf planets are also much smaller than
regular planets and take much longer to complete their orbit due to how slow they are moving.
Pluto recently became a dwarf planet due to is small size and the fact that its path is elliptical and
obstructed when it passes through the Kuiper belt. It is between 4,436,820,000 km and
7,375,930,000 km from the sun, has a diameter of 2,370 km and a mass of 1.3x10 22kg. Pluto takes
248 years to orbit the sun and 6 days and 9 hours to rotate on its axis. It was first discovered in 1930
and has 5 moons.
https://www.bobthealien.co.uk/solarsystem/innerplanets.htm
https://www.bobthealien.co.uk/solarsystem/outerplanets.htm
https://www.bobthealien.co.uk/dwarf/index.htm
https://www.bobthealien.co.uk/solarsystem/table.htm
Prominent moons in our solar system
Titan is the second largest moon in the solar system, it orbits Saturn and is the only moon in the
solar system to have a thick atmosphere. It has a diameter of 5,150 km which makes it larger than
Unit 16: Astronomy and Space Science
A: Understand the fundamental aspects of the Solar System.
Section 1 – Components of the Inner and Outer Solar System
Known planets and their composition (rocky, gaseous and dwarf planets)
The planets in the solar system can be separated into two groups based on the composition and
distance from the sun. All the inner planets are small, have rocky, solid surfaces and either don’t
have a moon or have a small number of them. They are made up of a core, mantle and crust and
have a hard rocky surface. The outer planets are large and don’t have solid surfaces., They are
mostly made up of gas and all four have rings that spin around them. In comparison to the inner
planets, those found in the outer reaches of the solar system have considerably more moons
orbiting them. All the planets orbit the sun in and elliptical manner.
Mercury is the closest planet to the sun and has temperatures ranging from 400 oC to -180oC. It’s one
of the smallest planets in the solar system as it only has a diameter of 4,878km. It takes 88 days to
orbit the sun and 59 days to turn on its axis which is tilted at a 0.1 o. Mercury is 57,900,000km from
the sun with a mass of 3.30x1023 kg. It’s covered in craters, similar to the moon, due to meteorites
crashing into its surface. Its atmosphere is made of sodium and helium and it doesn’t have a moon.
Venus is the second closest planet to the sun and is the only planet in the solar system to rotate
clockwise. It is 108,160,000km from the sun, has a diameter of 12,104km and has a mass of
4.87x1024 kg. It takes 225 days to orbit the sun and 243 days to turn on its axis which is at an angle of
177o. Venus’s surface is covered in poisonous clouds containing sulfuric acid and its atmosphere
contains carbon dioxide and nitrogen. The atmosphere is so thick heat cannot escape in to space
meaning temperatures can reach up to 480 oC. Between 200 and 600 million years ago thousands of
volcanic eruptions covered its surface in lava meaning that difficult to find about its history as the
surface is relatively new in planetary terms.
Earth is the third planet from the sun and is the only planet in the solar system able to sustain life. It
is 149,600,000km from the sun, has a diameter of 12,756km and a mass of 5.97x10 24 kg. It takes 365
days to orbit the sun and takes 23 hours and 56 minutes to turn on its axis which is at a 23 o angle,
The atmosphere is mostly made up of Nitrogen, Oxygen and ozone molecules that absorb ultraviolet
light from the sun to prevent it from reaching earth. Earth only has one moon which that orbits the
earth every 27 days.
Mars is the fourth planet from the sun and is the last of the inner planets. It is 227,936,640km from
the sun, has a diameter of 6,794km and a mass of 6.42x10 23 kg. It takes 24 hours and 37 minutes to
spin on its axis which is at 25o and 687 days to orbit the sun. Mars has two moons, called Phobos and
Deimos, that are both irregularly shaped and take 8 and 30 hours to complete an orbit of the planet.
It’s atmosphere is made mostly of carbon dioxide and argon and has an average temperature of -
63oC. The surface of mars is covered in a layer of iron oxide and craters formed by ancient
meteorites. Mars was also once volcanically active and has the solar system’s largest volcano, which
is 27 kilometres high.
Jupiter is the first of the outer planets and the largest planet in our solar system. It is 778,369,000km
from the sun, with a diameter of 142,984km and a mass of 1.898x10 27 kg. Jupiter takes 9 hours and
55 minutes to spin on its axis which is at 3o and it takes 11 years to orbit the sun. It is made mostly of
, Emilia Hawkins
hydrogen and helium with a very small solid or liquid centre, where hydrogen atoms break down to
form a metallic liquid due to the high amounts of pressure. Jupiter has 79 moons, some of which are
larger than other planets in the solar system.
Saturn is the second of the outer planets. It is also made mostly of hydrogen and helium with a liquid
core but has huge rings surrounding it that can be seen using telescopes. Saturn takes 29 years to
orbit the sun but only 10 hours and 33 minutes to rotate on its axis which is at 27 o. It has a mass of
5.68x1026 kg, is 1,427,034,000 km away from the sun and has 82 moons. The rings of Saturn have a
width of over 270,000 kilometres and are made up of rocks and ice. It is believed that the rings were
formed when something collided with the moons orbiting Saturn, and the rock and ice spread out to
orbit Saturn.
Uranus is the third of the outer planets. It is made up of methane, hydrogen and helium with a small
rocky core that could be surrounded by water. It is 2,870,658,186km from the sun, has a diameter of
51,118km and a mass of 8.68x1025kg. It takes 84 years for Uranus to orbit the sun and 17 hours to
rotate on its axis which is at 98o. The planet was first discovered in 1781 and has 27 moons. Uranus is
the only planet to be tilted on its side, where the equator is nearly at a right angle to its orbit.
Neptune is the fourth and final outer planet. It is also made of hydrogen and helium along with
methane, which gives it its blue colour. It is 4,496,976,000 km from the sun, has a diameter of
49,532 km and a mass of 1.02x1026kg. Neptune has the strongest winds in the solar system as the
average speed is over 1,100 kilometres per hour, but can reach speeds of up to 2,000 kilometres per
hour. It takes Neptune 165 years to orbit the sun and 16 hours to rotate on its axis which is at 30 o. It
has 14 moons. Because it is the furthest planet from the sun, it takes the longest to orbit as it has
the furthest distance to travel and is moving at the slowest speed due to the sun’s weaker pull of
gravity.
There are 5 main dwarf planets in our solar system, four of which are located in the beyond Neptune
and one in the asteroid belt between Mars and Jupiter. Dwarf planets don’t have clear orbits and the
path they take is populated by other objects. The atmosphere and composition of these dwarf
planets is unknown, but is thought to contain nitrogen. Dwarf planets are also much smaller than
regular planets and take much longer to complete their orbit due to how slow they are moving.
Pluto recently became a dwarf planet due to is small size and the fact that its path is elliptical and
obstructed when it passes through the Kuiper belt. It is between 4,436,820,000 km and
7,375,930,000 km from the sun, has a diameter of 2,370 km and a mass of 1.3x10 22kg. Pluto takes
248 years to orbit the sun and 6 days and 9 hours to rotate on its axis. It was first discovered in 1930
and has 5 moons.
https://www.bobthealien.co.uk/solarsystem/innerplanets.htm
https://www.bobthealien.co.uk/solarsystem/outerplanets.htm
https://www.bobthealien.co.uk/dwarf/index.htm
https://www.bobthealien.co.uk/solarsystem/table.htm
Prominent moons in our solar system
Titan is the second largest moon in the solar system, it orbits Saturn and is the only moon in the
solar system to have a thick atmosphere. It has a diameter of 5,150 km which makes it larger than
