An Expanding Universe

Redshift, Blueshift and the Doppler Effect

EMS Review

• The shorter the wavelength, the higher the frequency

• The longer the wavelength, the lower the frequency

• Red wavelengths of light are longer than blue wavelengths of light

• Star composition can be determined by the spectrum of the gases present

Doppler Waves• As an object moves away from you, the waves

spread out. Wavelength gets longer and frequency decreases.

• As an object moves towards you, the waves bunch up. Wavelength gets shorter and frequency increases

Doppler Waves

• When dealing with light waves, we say that the object has red-shifted because the waves move towards the red end of the spectrum

• As an object moves away from you, the waves spread out. Wavelength gets longer and frequency decreases.

Red shift, moving away.

Doppler Waves

• We say that the object has blue-shifted because the waves move towards the blue end of the spectrum.

• As an object moves towards you, the waves bunch up. Wavelength gets shorter and frequency increases

Blue shift, moving towards.

How can we tell that the universe is expanding?

As an object moves away from you, the object’s spectrum of gases shifts to the red side of the spectrum

https://www.youtube.com/watch?v=FhfnqboacV0How can we tell that the universe is expanding?

Shifting Spectrums

Which galaxy or planet is moving at the same speed as the nearby star?

• VENUS

Red shift/Blue shift Practice

Red Blue

Nearby Star

Andromeda Galaxy

Bernard’s Galaxy

Bear Galaxy

Venus

SR - 5

What galaxies or planets are moving toward the nearby star?

• Andromeda

Red shift/Blue shift Practice

Red Blue

Nearby Star

Andromeda Galaxy

Bernard’s Galaxy

Bear Galaxy

Venus

SR - 5

What galaxies or planets are moving awaythe nearby star?

Red shift/Blue shift Practice

Red Blue

Nearby Star

Andromeda Galaxy

Bernard’s Galaxy

Bear Galaxy

Venus

SR - 5

Bernard’s, Bear,SR-5.

Is the Andromeda galaxy red or blue shifted?

Red shift/Blue shift Practice

Red Blue

Nearby Star

Andromeda Galaxy

Bernard’s Galaxy

Bear Galaxy

Venus

SR - 5

Blue Shifted

Which galaxy or planet is moving fastest awayfrom the nearby star?

Red shift/Blue shift Practice

Red Blue

Nearby Star

Andromeda Galaxy

Bernard’s Galaxy

Bear Galaxy

Venus

SR - 5

Benard’s itis the mostred shifted

Which galaxy or planet is moving the slowest away from the nearby star?

Red shift/Blue shift Practice

Red Blue

Nearby Star

Andromeda Galaxy

Bernard’s Galaxy

Bear Galaxy

Venus

SR - 5

SR- 5