Earth in space

• The planets, in order from the sun are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
• Galaxy - A huge collection of gas, dust and billions of stars and their solar systems, all held together by gravity
• A planetary system is a set of gravitationally bound non-stellar objects in orbit around a star or star system
• Asteroids are small rocky objects that orbit the sun like planets
• asteroids are much smaller than planets
• A trojan is a small celestial body mostly asteroids. They share the orbit of a larger body such as planets or large moon
• The first 4 planets are called inner/terrestial planets
• A celestial bodies are formed from dust and gas
• Most asteroids are found in the asteroid belt
• The asteroid belt is a ring around the sun between the orbits of mars and jupiter
• Trojan -asteroid Group
• There can be around 515,000 km between any two asteroids
• asteroids are held in place by gravity
• when an asteroid goes through a change in direction of movement due to changes in force of gravity it can set up another orbit. some of these orbits may cross paths. This can lead to collision
• Craters are made/formed when an asteroid collides with a planet or moon
• there is no atmosphere on our moon
• The side of the moon that we can see is known as the near side
• The side we cant see is known as the far side
• Climate change depends on the amount of heat and sunlight recieved
• mass extinction is when more than 75% of the species on the planet get extinct
• sun emits light because of nuclear fusion
• nuclear fusion is a nucliei of hydrogen that fused under temperature and pressure and forms heavier nucliei of helium
• All stars emit light because of nuclear fusion
• hydrogen is fuel
• we have crossed 50% of the suns life