How does red shift provide evidence of an expanding universe?(5 points)

1. **Doppler Effect**: Redshift occurs due to the Doppler effect, where light from moving objects changes frequency. Objects moving away from us show longer (redder) wavelengths.

2. **Observed Redshift**: Astronomers observe that most distant galaxies exhibit redshift, indicating they are moving away from Earth.

3. **Hubble's Law**: Edwin Hubble discovered a correlation between a galaxy's distance and its redshift—more distant galaxies have higher redshifts, supporting expansion.

4. **Expanding Universe Model**: The redshift data suggests that space itself is expanding, causing galaxies to recede from each other over time.

5. **Big Bang Theory**: The concept of redshift aligns with the Big Bang theory, indicating that the universe has been expanding since its inception.