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Proof

The document discusses evidence that supports the Big Bang theory, including the redshift of galaxies indicating expansion, detection of the cosmic microwave background radiation, composition of early galaxies matching predictions, and observation that older galaxies are very different than newer galaxies.

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32 views1 page

Proof

The document discusses evidence that supports the Big Bang theory, including the redshift of galaxies indicating expansion, detection of the cosmic microwave background radiation, composition of early galaxies matching predictions, and observation that older galaxies are very different than newer galaxies.

Uploaded by

kharlwaramphool1
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Tuesday, November 7, 2023 9:01 PM

Redshift of Galaxies
The light we observe from galaxies has been stretched by the time it reaches us. It looks redder
than it should. This redshift is the result of galaxies moving away from us. Observations show
that pretty much everything in the Universe is moving apart. The redshift of distant galaxies tells
us the Universe is expanding.
If you could wind time backwards, you would see galaxies getting closer together. If you could
go back far enough, everything in the Universe would have been in one place.

Cosmic Microwave Backgroud


2. Microwave Background
A long, long time ago, the whole Universe was very hot. As it grew in the size, the heat left a
"glow" which fills the entire Universe. The Big Bang theory predicts this glow should still exist. It
also predicts that we should be able to detect this glow as microwave light.
Scientist have found this Cosmic Microwave Background. They have accurately measured it
using orbiting detectors. It is very good evidence that the Big Bang theory is correct.
3. Mixture of Elements
Some chemical elements were created soon after the Big Bang. Elements like hydrogen and helium. The Big
Bang theory predicts how much of each element was made in the early universe. When astronomers look at
very old galaxies and stars, the amount of each chemical they see agrees with the Big Bang theory.
You cannot look for this evidence in new stars, like the Sun. This is because newer stars contain chemical
elements made by older stars. So the chemical make-up of new stars is very different from stars which existed
soon after the Big Bang.

4. Looking back in time


There is an alternative to the Big Bang theory. It is called the Steady State theory. In this theory, the Universe
does not change much over time.
Remember - light takes a long time to travel across the Universe. So when we look at galaxies which are very
far away, we are also looking back in time.
This means we can see that very old galaxies are very different from newer galaxies. This shows the Universe
has changed. This evidence fits better with the Big Bang theory than the Steady State theory.

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