Question

Imagine that the light you observe from space is exhibiting a redshift. This would mean that the Universe is Choose one: A. traveling faster than the speed of light. B. traveling slower than the speed of sound. C. expanding. D. collapsing.

Answer 1

Answer: C. Expanding

Explanation:

When an object moves away from an observer, the light waves emitted by the object are stretched out making them have move towards the red end of the electromagnetic spectrum, where light has a longer wavelength. This phenomenon is known as the redshift (cosmological redshift). For most astronomical objects, the observed spectral lines are all shifted to longer wavelengths. It is caused solely by the expansion of the Universe and thus, the value of a redshift indicates the recession velocity of the expanding object, or its distance.

Redshift is opposed to the blueshift. Blue light wavelengths tend to be closer together hence blueshift light tends to be emitted from objects that are collapsing.