Redshift

Definition

Redshift is the phenomenon where the wavelength of light from an object increases, making it appear more red. It is often observed in light from galaxies moving away from us, indicating the expansion of the universe.

5 Must Know Facts For Your Next Test

1. Redshift is a key evidence supporting the Big Bang theory and the expanding universe.
2. It can be measured using spectral lines, which shift towards longer wavelengths.
3. The amount of redshift is directly related to the velocity at which an object is moving away.
4. Cosmological redshift occurs due to the expansion of space itself, stretching light over vast distances.
5. Edwin Hubble's observation of redshifts in distant galaxies led to the formulation of Hubble's Law.

Review Questions

• What does a higher redshift indicate about a galaxy’s movement relative to Earth?
• How does redshift provide evidence for an expanding universe?
• What role did Edwin Hubble play in our understanding of redshift?

Related terms

Doppler Effect:

A change in frequency or wavelength of a wave in relation to an observer moving relative to the source of the wave.

Hubble's Law:

The observation that more distant galaxies are receding faster, implying that the universe is expanding.

Cosmological Redshift:

Redshift caused by the expansion of space itself rather than movement through space.