Lesson Aim To consider the evidence for the Big Bang theory.
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Transcript of Lesson Aim To consider the evidence for the Big Bang theory.
Evidence for the Big Bang
The evidence for the Big Bang is circumstantial and is inferred from what we can observe today.
Some is based on empirical evidence and some is theoretical.
The Evidence: Expanding Universe
The Doppler Effect – if you’ve heard a fire engine (nee-naw, nee-naw) you notice the pitch of the noise changes.
This is the Doppler Effect of sound waves contracting and stretching.
A similar process happens with light.
Doppler Effect
http://www.youtube.com/watch?v=imoxDcn2Sgo&feature=related
Edwin Hubble
The Hubble telescope observed that the light coming from distant galaxies was all shifted towards the red light of the light spectrum.
This somehow enables scientists to identify the source of the light
Think of it as light carrying a certain signature (Or an mp3 file creating info on when it was
created) This is known as the cosmological red shift
This cosmological red shift implies an expanding universe – as light waves would have come from the same source and is expanding outwards away from the original source
Einstein A few years earlier Einstein
argued that all systems in the Universe had a finite source of energy
Energy in the Universe is not infinite therefore the Universe could not have existed for all eternity
The logical conclusion of this is that the Universe must have had some sort of beginning
Implications
Everything in the Universe appeared to be expanding away from a central point so there must have been a starting off point (a beginning).
Einstein’s theory of relativity supported this view.
Cosmic Background Radiation
Think of a sparkler on Bonfire night. You light it and it gets very hot and also heats up whatever is around it.
The Big Bang obviously created a huge amount of heat and this is still around today
This heat is called cosmic background radiation
Cosmic Background Radiation
Think of a sparkler on Bonfire night. You light it and it gets very hot and also heats up whatever is around it.
The Big Bang obviously created a huge amount of heat and this is still around today
This heat is called cosmic background radiation
Cosmic Background Radiation
Back in 1965 astronomers picked up radio signals from the universe – a sort of background fuzz
They identified this as cosmic background radiation
This provides evidence that the Big Bang actually happened
Cosmic Background Radiation
Back in 1965 astronomers picked up radio signals from the universe – a sort of background fuzz
They identified this as cosmic background radiation
This provides evidence that the Big Bang actually happened
Cooking a Universe
Is it possible to eat a meal (without knowing the ingredients) and then guess what was in it and how it was made??
Cooking a Universe
We can do something similar with the Big Bang There are 117 elements in the periodic table The amount of elements in the Universe points
towards a Big Bang 90% of the elements are Hydrogen atoms – this
is exactly what we would expect if the Universe had started with a Big Bang
Discussion Point
If the Big Bang theory is correct, what might this mean for religious beliefs???
6 minutes
“If the density of the universe one second after the Big Bang had been greater by one part in a thousand billion, the Universe would have recollapsed after 10 years. On the other hand, if the density of the Universe at that time had been less by the same amount, the Universe would have been essentially empty since it was about 10 years old. How was it that the initial density of the Universe was chosen so carefully?”
Professor Steven Hawking