What is the interpretation of a redshift larger than 1?
A) The object is moving faster than the speed of light.
B) The universe has more than doubled in size since the light from that object was emitted.
C) The object has an extremely large peculiar velocity.
D) The light was shifted to longer wavelengths from gravitational radiation.
E) The rate of expansion of the universe is increasing.

Question

Quizplus · Accepted Answer

A redshift larger than 1 means that the wavelength of the light emitted by the object has been stretched to more than twice its original length. This indicates that the expansion of the universe has caused the object to move away from us at a rate greater than the speed of light, and since this is not possible according to the laws of physics, the most likely explanation is that the universe has expanded since the light was emitted, which leads to choice B.

What Is the Interpretation of a Redshift Larger Than 1