Question

15 explain edwin hubbles discovery of the redshift in light from distant galaxies and how this supports the idea that the universe is expanding. enter your answer in the box provided.

Explanation:

• Redshift discovery: Hubble found distant galaxy light redshifted.
• Doppler - like effect (analogy): Stretch of wavelength (redshift) suggests motion away.
• Distance - redshift relation: Farther galaxies have more redshift (Hubble's law \(v = H_0d\), \(v\) - velocity, \(H_0\) - Hubble constant, \(d\) - distance).
• Expansion implication: Galaxies moving apart (as per redshift) means universe is expanding.

Answer:

Edwin Hubble discovered that light from distant galaxies is redshifted. This means the wavelength of the light is stretched, indicating the galaxies are moving away. The more distant a galaxy, the greater its redshift. This is similar to the Doppler effect (but cosmological redshift is due to space expansion). If galaxies are moving apart, it implies the universe is expanding.