The Universe – WJECCosmic microwave background radiation
The study of atomic absorption spectra allows us to determine the chemical make-up of stars. It shows that galaxies are moving away from us in an expanding Universe.
In 1927 Georges Lemaître proposed that the Universe began with an explosion called the Big Bang. Hubble’s research into the red shift of galaxy light showed that the Universe was expanding, and that the galaxies had originated from a single point. If the expansion of the Universe was reversed, then everything would revert back to a single point.
This evidence supported Lemaître’s Big BangThe scientific theory that describes the early development of the Universe. It says that the whole Universe expanded out from a small, hot, dense region..
In 1948, it was suggested that if the Universe started with an explosion, there should be microwave background radiation in space left over from the explosion. This radiation was discovered in 1964. It is called cosmic microwave background radiationRadiation that started life as gamma waves but was stretched into longer wavelength microwaves by the Universe expanding. or CMBR.
CMBR is a second piece of evidence to show the expansion of space, and this supports the Big Bang model of the origin of the Universe. The short wavelengths of the gamma radiation emitted in the initial explosion are believed to have become stretched due to the expansion of space into longer wavelength microwaves.
