Space

• The order of the planets in our solar system is:

  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
  • Pluto (now classified as a dwarf planet)
• To remember the order of the planets, use the mnemonic: "My Very Easy Method Just Speeds Up Naming Planets"
• The life cycle of a star starts as a cloud of dust and gas, which comes together under gravity to form a main sequence star
• Depending on the size of the star, it will either become a red giant and then a white dwarf (or black dwarf for smaller stars), or a red supergiant, undergo supernova, and form a black hole or neutron star
• Our Sun is a second-generation star, containing heavy elements like iron
• Stars undergo nuclear fusion in their cores, releasing energy in the form of light, heat, and sometimes sound
• When a star runs out of fuel, it reaches the end of its life cycle
• Artificial satellites are man-made objects orbiting the Earth, while natural satellites like the moon naturally orbit the Earth
• Speed is the rate of motion, while velocity includes direction and is a vector quantity
• Redshift in light from stars indicates they are moving away from us, while blueshift indicates they are moving towards us
• The solar system consists of the sun at the center, with eight main planets orbiting around it
• Mercury, Venus, Earth, and Mars are relatively small rocky planets
• Jupiter, Saturn, Uranus, and Neptune are much larger gas giants
• Besides planets, the solar system also contains moons, asteroids, and comets
• Moons are natural satellites that orbit planets
• Most planets have at least one moon, while some have a large number of moons
• Stars like the sun form from clouds of dust and gas known as nebulae
• In the first stage, gravity causes the cloud of dust and gas to collapse, forming a protostar
• If the temperature of the protostar gets high enough, hydrogen nuclei join together to form helium through nuclear fusion
• Nuclear fusion releases a huge amount of energy, turning the protostar into a star
• Two opposing forces act within the star: gravity, which tends to make the star collapse, and the force due to fusion energy, which tends to make the star expand
• The balance between these two forces creates an equilibrium within the star
• The furthest galaxy show the biggest red shift meaning that the furthest galaxies are moving fastest so the universe is expanding.
• While the star is in the main sequence stage of its life cycle gravitational forces inwards and forces as a result of fusion reactions outwards are in equilibrium.
• when the universe began, it was extremely hot and dense.
• The force of gravity causes satellite to accelerate. The acceleration causes a change in direction so the velocity changes because direction changes.

  
• Satellites orbit the Earth because they’re moving parallel to the surface of the Earth gravity accelerates them down towards us. This changes the direction of the satellite but not its speed. This means their velocity changing.
• The universe now contains a large variety of different elements describe how this happened [4]

  • Fusion takes place within the star
  • Hydrogen formed into helium
  • Fusion continued informed large elements
  • Elements heavier than iron were formed in the supernova
  • Heavy elements were scattered by the supernova explosion
• The Big Bang theory suggests that the universe began as a single point and has been expanding ever since.