The Big Bang Theory

Question	Answer
The doppler effect The changing of wavelength and frequency of waves relative to the observer	When the source moves away from the observer, the observed wavelength increases and the frequency decreases
The source moves towards the observer, the observed wavelength decreases and and the frequency increases	Sirens are an example
galaxies are a large collection of stars	Red-shift- Increase in wavelength of electromagnetic waves emitted by a star ot galaxy due to its motion away from us
the faster the speed of the star, the greater the red-shift is	Galaxies further away from us are moving faster than ones which are closer
Bluue-shift- when a galaxy is moving towards us and the rays from the galaxy are moving towards the darker end of the spectrum	Image: redshift (image/jpg)
All the distant galaxies are moving away from each other, so the whole universe is expanding	...
The Big Bang Theory	If it is now expanding, it suggests there was a massive explosion which started at a very small, initial point where the universe was created
The universe has been expanding ever since the big bang, high energy gamma rad. would have been produced -As the universe expanded it would have become lower-energy rad.	Cosmic microwave background radiation (CMBR) is electromagnetic radiation, created just after the Big Bang; can only be explained by the BB

Resource summary

	Created by oliviabaines over 10 years ago