Space

• A celestial body is a nartural object found in spaces.
• Examples of celestial bodies (smallest to largest) -

  • Moons - Lumps of matter that orbit planets.
  • Planets - Large balls of matter that orbit a star but do not emit light.
  • Stars - Massive balls of matter emitting light and heat.
  • Solar Systems - Consists of a central star orbited by planets.
  • Galaxies - Large collections of stars.
  • Universes - Consist of many galaxies separated by lots of empty space.
• There are 8 planets orbiting the Sun (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune).
• Together, with other objects like comets, asteroids, meteors and meteorites, they make up The Solar System.
• Asteroids are lumps of rocks that are smaller than planets.

  Comets are made of ice and rock.

  Meteors are bits of rock or dust that have broken off asteroids of comets.Meteors that do not fully disintegrate before reaching the surface of the Earth are called meteorites.
• Stars -

  • A star is a huge sphere of hot gas that emits heat and light.
  • Stars are sometimes orbited by planets.Our star is called the Sun.
  • The Sun is almost entirely made from hydrogen (91%) and Helium (8%). The sun emits energy by turning hydrogen into helium.
  • All stars begin life in the same way. Stars are born in clouds of dust and gas scattered throughout galaxies called nebula or nebulae (plural).
• Galaxies -

  • Galaxies are groups of stars.
  • Our Galaxy is called the Milky Way.
• Galaxies: 2 -

  • On average, each galaxy contains 100 million stars and NASA estimates there are 200 billion galaxies in the Universe.
  • Black Holes are often found at the centre of galaxies. At the centre of our galaxy there is a supermassive black hole.
• Exoplanets _

  • Exoplanets are planets that are out with our Solar System.
  • Humans require 5 basic needs to survive: Water, Oxygen, Food, Shelter, Warmth. To make an Exoplanets habitable, it must have all of these things.