Solar System

• Astronomical Unit (A.U.) is the average distance between the Earth and the Sun, approximately 150 million kilometres.
• Light Years (ly) is the distance travelled by light in one year, as light moves 300,000 km every second.
• 1 A.U = 1.5 x 10^8 km.
• 1 light year = 9.5 x 10^12 km.
• 1 A.U = 1.5 x 10 8 km and 1 ly = 9.5 x 10 12 km.
• Mercury is the smallest planet in the Solar System with a surface similar to the surface of the moon, featuring asteroid craters and cliffs (tens of km high), plains, mountains and valleys.
• Mercury has no atmosphere, making the sky appear dark in the outer space.
• Venus, known as the 'greenhouse' planet, has a high content of carbon dioxide in its atmosphere. Causing it to have alot of greenhouse effect.
• Venus and Earth have the same size and age.
• Earth is the only place in the universe that is inhabited by living things, with a layer of air known as atmosphere that protects the surface of the Earth from solar wind, harmful ultraviolet rays and radiation from outer space.
• More than 71% of Earth is covered in water and 29% is land.
• Mars, known as the Red Planet, has two moons, Phobos and Demos, a surface area of 25% of the Earth and its mass is 10% of the Earth.
• Jupiter, the largest planet in the Solar System, has a mass of 320 times of the Earth, twice the amount of all the planets in the solar system, and is able to deflect huge objects from hitting Earth with its strong gravity.
• Saturn, the second largest planet in the Solar System, is classified as a 'giant gas' planet and has a ring system which mostly comprises of ice with a small amount of rocky material and dust.
• Uranus, the third biggest planet in the Solar System, its first elements in the interior are ice and rock.
• Neptune, a 'giant gas' planet, takes almost 165 years to orbit the Sun.
• Order of Planets: Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
• Mercury is closest to the sun and orbits it every 87 days.
• Mercury has no atmosphere, thus light cannot be scattered.

  The sky appears dark in the outer space.
• Venus rotates from east to west, different from all the other planets. Thus the sun rises from the west.
• The climate on Venus is very challenging, temperate approximately 460c
• Mars is divided into 2 different areas.

  1. Brighter area: covered in dust and reddish sand
  2. Poles: contain frozen water and carbon dioxide
• Jupiter has the most number of natural satelites (67 moons)
• Saturn has 62 moon

  The biggest moon is the Titan, it is even bigger than Mercury.
• Uranus also has rings but they are thin and dark.
• Uranus has 27 moons
• Uranus’ axis of rotation is tilted, almost parallel to its orbit around the sun.
• It takes Uranus 84 years to orbit the sun.
• Neptune takes 165 years to orbit around the sun.
• The temperature of planets in our solar system can vary depending on their distance from the sun.
• Mercury, the planet closest to the sun, can reach temperatures as high as 427 degrees Celsius on its sun-facing side and as low as -173 degrees Celsius on its dark side.
• Venus, a greenhouse planet, has an atmospheric layer that traps heat, making it the hottest planet in the solar system with a temperature of 462 degrees Celsius.
• Earth, with clouds and an atmosphere, has an average temperature of around 30 degrees Celsius in Malaysia, and the coldest point is negative 89.2 degrees Celsius.
• Mars, with a surface pressure less than one percent of Earth's, has a temperature range from negative 143 to 35 degrees Celsius.
• The Earth's gravity is 9.8, while Mercury's is 3.7, Venus's is 8.87, Mars's is 3.7, Jupiter's is 24.79, Saturn's is 95, Uranus's is 14.3, and Neptune's is 17.1. (m s-2)
• Mercury completes one orbit around the Sun in 88 days, Venus in 224 days, Earth in 365 days, Mars in 687 days, Jupiter in 11.9 years, Saturn in 29.5 years, Uranus in 84 years, and Neptune in 164.8 years.
• All planets rotate from west to east, except Venus and Uranus which rotate in the opposite direction.
• Mercury, Venus, and Mars are closer to the Sun, have lower mass, and therefore have lower gravity.
• Jupiter, Saturn, Uranus, and Neptune are further from the Sun, have higher mass, and therefore have higher gravity.
• The giant planets Jupiter, Saturn, Uranus, and Neptune are all very cold, with temperatures ranging from -228 to -200 degrees Celsius. This is because they receive very little sunlight