Theories about the Universe's development, such as the Big Bang theory, are based on astronomical observations such as red-shift and cosmic microwave background radiation.
According to the Big BangThe scientific theory that describes the early development of the Universe. theory, about 13.8 billion years ago the whole Universe was a very small, extremely hot and dense region. From this tiny point, the whole Universe expanded outwards to what exists today.
Evidence of expansion
Scientists have discovered that red-shiftThe change in wavelength of light from a distant star moving away from Earth. data provides evidence that the Universe, including space itself, is expanding. Astronomers have also discovered a cosmic microwave background radiation (CMBR). This comes from all directions in space and has a temperature of about –270 °C. The CMBR is the remains of the thermal energy from the Big Bang, spread thinly across the whole Universe.
Professor Brian Cox explains how evidence for the Big Bang can be found by analysing the colour of starlight
Prediction from Big Bang theory
Evidence observed
Does evidence support the Big Bang theory?
More distant galaxies should move away faster
More distant galaxies have greater red-shift
Yes
Initial heat from the Big Bang should now be thinly spread across the whole Universe
CMBR is everywhere at a temperature of about -270°C
Yes
Prediction from Big Bang theory
More distant galaxies should move away faster
Evidence observed
More distant galaxies have greater red-shift
Does evidence support the Big Bang theory?
Yes
Prediction from Big Bang theory
Initial heat from the Big Bang should now be thinly spread across the whole Universe
Evidence observed
CMBR is everywhere at a temperature of about -270°C
