Doppler and Redshift Review

What best describes the doppler effect?

• An apparent change in frequency of a wave due to the relative motion between a wave source and an observer
• When sound changes pitch
• When light changes color
• An apparent change in the amplitude of a wave due to the relative motion between a wave source and an observer.

If a star is being observed from Earth and it's light has shifted towards the blue side of the electromagnetic spectrum it would be...

• Moving towards the Earth
• Moving away from the Earth
• This is a trick question that cannot be answered
• It isn't a star, it is a very large blueberry.

If a star is being observed from Earth and it's light has shifted towards the red side of the electromagnetic spectrum it would be...

• Moving towards the Earth
• Moving away from the Earth
• This is a trick question that cannot be answered
• It isn't a star, it is a very large blueberry.

The vast majority of galaxies in our universe are moving away from us.  We know this because we observe __________ in the galaxies absorption spectra.

• Redshift
• Blueshift
• Turbulance
• Superposition

Use the image to identify the motion of the object relative to Earth.  Compare the absorption spectra of the star to what the star would look like if it were not moving at all relative to Earth.

• It is not moving
• It is moving away from Earth (Redshift)
• It is moving towards Earth (Blueshift)
• It is moving towards Earth (Redshift)

Use the image to identify the motion of the object relative to Earth.  Compare the absorption spectra of the star to what the star would look like if it were not moving at all relative to Earth.

• It is not moving relative to Earth
• It is moving away from Earth (Redshift)
• It is moving towards Earth (Blueshift)
• It is moving towards Earth (Redshift)

Use the image to identify the motion of the object relative to Earth.  Compare the absorption spectra of the star to what the star would look like if it were not moving at all relative to Earth.

• It is not moving relative to Earth
• It is moving away from Earth (Redshift)
• It is moving towards Earth (Blueshift)
• It is moving towards Earth (Redshift)

An object that is moving VERY fast away from Earth would have ________ than an object that is moving very slow away from Earth.

• More Redshift
• More Blueshift
• Less Redshift
• Less Blueshift

An object that is moving VERY fast towards the Earth would have ________ than an object that is moving very slow towards the Earth.

• More Redshift
• More Blueshift
• Less Redshift
• Less Blueshift

Which discovery(ies) came from our understanding redshift/ blueshift?

• The universe is expanding
• Most galaxies are moving away from us
• Andromeda galaxy will collide with the Milky way in 3.75 billion years
• All of the above (and many more)