Red Shift

What is the Doppler Effect?

The change in frequency or wavelength due to the relative motion between a source and an observer.

What happens as an object moves towards an observer?

The wavelength of light decreases causing blueshift as the light moves to the blue end of the spectrum.

What happens if an object moves away from the observer?

The wavelength of light increases causing redshift as the light moves to the red end of the spectrum.

What is red-shift?

The observed increase in the wavelength of light due to the source moving away from the observer.

What does red-shifted galaxies indicate?

Galaxies are moving away from us meaning that the universe is expanding, supporting the big bang theory.

What is the idea of the big bang theory?

The universe began from a very small, hot and dense region and a series of explosions caused the universe to expand and cool.

What is evidence for the big bang?

Light spectrums show galaxies are red-shifted meaning that the universe is expanding which is what happens in an explosion as matter moves out in all directions.

Do astronomers understand all of the universe?

Most but not all.

What does rotation and motion of galaxies suggest?

There is more matter in the universe than we can account for, the unseen matter is called dark matter.

Measurements of the universe’s expansion using supernovas suggest it is expanding at a first rate what is suggested to have caused this?

The accelerated motion is caused by dark energy pushing everything in the universe apart.