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Formation of the Universe

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What is the Big Bang theory?The Big Bang Theory states that the Universe began 13.6 billion

yrs ago as a singularity and has been expanding ever since.But it wasn’t big, and there was no bang!

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Prediction: The universe is expanding

Observation: Galaxies are moving apart from each other

Testing the Big Bang model

Big Bang Proof

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Is the Universe expanding?

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Scientists examining the light emitted by stars observe dark lines in the spectrum caused by different elements, such helium, in the stars being studied.

What is Red Shift?

This red shift suggests that distant galaxies are moving away from Earth and supports the idea of an expanding Universe.

Edwin Hubble observed that the pattern of dark lines produced by the light coming from distant galaxies is shifted towards the red end of the spectrum.

Red shift occurs because of the Doppler effect, which can be observed in sound waves and electromagnetic waves.

The observation of red shift is a key piece of evidence for the Big Bang theory about the origin of the Universe.

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What is Red Shift?

Red shift occurs because of the Doppler effect, which can be observed in sound waves and electromagnetic waves.

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What is the Doppler effect?

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What is the Doppler effect?

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The Doppler effect means that sound moving away from an observer appears to be lower in frequency.

It has also been observed that the further away a galaxy is, the greater the amount of red shift.

How does the Doppler effect work in space?

This means the distant galaxies must be moving away from the Earth.

The same thing happens with light from distant galaxies, which appears to be shifted towards the low frequency, red end of the spectrum.

This means that very distant galaxies are moving fasterall of which is evidence for the Big Bang theory.

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Prediction: If the universe was denser and hotter in the past, we should see evidence of left-over heat from early universe.

Observation: Left-over heat from the early universe. (Penzias and Wilson, 1965)

Testing the Big Bang model

Big Bang Proof

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Evidence of the Big Bang – CMB

The other key piece of evidence for the Big Bang theory is cosmic microwave background radiation (CMB).

CMB is microwave radiation coming from every direction in space

CMB was discovered accidentally right in New Jersey. Searching for radio waves in the Milky Way, they heard a humming sound in their antenna that they couldn’t explain.

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Space Sounds

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The Universe from beginning to end

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The Future of the Universe

Dark Energy

74%

Dark Matter22%

Normal Matter4%

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The Future of the Universe

Dark Matter, discovered by Vera Rubin, is a new and unknown form of matter that exists. But its gravity works the same way as matter.

In order for a new particle to behave as dark matter, it must be heavy (probably heavier than a neutron) and weakly interacting with normal matter so that it does not emit light.

Dark matter must be the basic building block of the largest structures in the universe: galaxies and clusters.

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The Future of the Universe

We know the universe is expanding faster than we thought. The answer may be dark energy.

We don’t know what dark energy is, but it is everywhere and it’s force increases as space expands.

Therefore, as the Universe expands, gravity weakens and dark energy strengthens.

This supports an open Universe theory.

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The big-bang theory states that the Universe is expanding due to a large ‘explosion’ (big bang) billions of years ago.

Evidence to support this theory includes:

1. The Cosmic Microwave Background Radiation (CMB), which is thought to be an ‘echo’ of the initial explosion.

2. Hubble’s observations about red shift.;This theory gives rise to different fates for the Universe:

1.If the mass of the Universe is smaller, it will eventually start to contract due to gravity – closed Universe.

2.If the mass of the Universe is large enough, it will expand forever as there is not enough gravity to halt its expansion – open Universe. Dark matter and dark energy may prove this!

Summary

Cosmic Microwave Background Radiation

big bang theory

red shift

Closed Universe

open Universe matter energy