The Origins of the universe

The Origins of the universe

1. The ever-expanding universe

   • We can find out lots of things about stars and galaxies by studying the light from them. We can use a prism to split the light into a spectrum. The wavelength of light increases across the spectrum from blue to red. We can tell from the spectrum if a star or galaxy is moving towards or away from us. This is because:
     • - the light waves are stretched out if the star or galaxy is moving away from us. We call this red shift because the spectrum of light is shifted towards the red part of the spectrum
       • - the light waves are squashed together if the star or galaxy is moving towards us. We call this blue shift because the spectrum of light is shifted towards the blue part of the spectrum
   • The faster a star or galaxy is moving towards or away from us, the bigger the shift is
     • Red shifts and blue shifts follow the Doppler effect
     • Red shift and blue shift show that all galaxies are moving away from each other, proving that the whole universe is expanding

2. The big band theory

   • The Big Bang Theory tries to explain the expanding Universe. It states:
     • - the Universe is expanding after exploding suddenly in a Big Bang from a very small initial point
       • - space, time and matter were created in the Big Bang
     • In 1965, it was discovered that microwaves were coming from every direction in space. The existence of this background microwave radiation can only be explained by the Big Bang Theory