Types of Electromagnetic energy

Red light is low energy – coolBlue is high energy - hot

Low energyHigh energy

Long waveShort wave

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RED SHIFTAND

Evidence of an Expanding Universe

• Explain how Red shift explains the movement of the universe.

• Explain the Big Bang Theory.

KEY WORDSRed Shift Doppler Effect

• There is evidence that the universe is expanding:

- Analyzed light given off by stars.

Light waves work exactly like any other wave:• Waves can come far apart - long wavelength• Waves can come close together - short

wavelength

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Effect of motion on waves is the Doppler Effect.

Not moving – all waves move away evenly.

Moving – compressed in front, spread out in back.

High pitch Low pitch

Motion affects light waves too.

• when light waves are compressed close together, the colour of the light appears more purple – “blue shift”

• when light waves are spread out, the colour appears more red – “red shift”

• Every star and galaxy shows a red shift.Things are moving AWAY - expanding universe.

• Far away galaxies show most red shift - faster.

“red shift”

“blue shift”

normal

If the universe is expanding:• Must have started out from one point –

singularityAll the matter in the universe was packed into one, extremely dense hot mass, under unimaginable pressure.• About 10-15 billion years ago.• There is evidence – red shift, radiation…• Scientists cannot yet explain “how” and “why.”• Big Bang is not the only explanation of the origin

of the universe.

But beliefs are not theories – only theories can be scientifically tested and proven.