If we went back in time 10 billion years,would we expect Hubble's constant to be identical to the present-day Hubble constant?
A)Yes,a constant never changes.
B)No,Hubble's constant is roughly equal to 1 divided by the age of the universe,and 10 billion is a substantial enough number to notice a difference.
C)If we went back further in time,it would be different,but 10 billion years is not enough.
D)It would only change if we went 10 billion years into the future.

Question

Quizplus · Accepted Answer

Hubble's constant is not actually a constant, but rather a measurement of the rate at which the universe is expanding. This rate changes as the universe ages, so if we went back 10 billion years, we would expect the Hubble constant to be different than it is today. Specifically, since Hubble's constant is roughly equal to 1 divided by the age of the universe, we would expect it to be about 1/10 billion years or 0.0000001 per year at that time.

If We Went Back in Time 10 Billion Years,would We