Redshift measurements show the universe is expanding, and the rate of expansion has been accelerating since 5 (is that the correct number?) billion years ago. It occurred to me that instead of space expanding (a concept with a few unresolved problems such as what is dark energy?), the same redshift effect could be caused by time speeding up over the life of the universe. This would appear similar to the redshift that occurs when light leaves a gravity well. Time runs "slower" in intense gravity. As the light leaves the gravity well, it is redshifted as it moves out into space where time "runs faster". Perhaps someone can tell me what is the correct terminology for "fast" time and slow "time". (Is time "dilation" slow time? What is the term for "fast" time? Un-dilation? :) My question 1 is: Is time "speeding up" exactly the same as space expanding? It seems to me the answer is no, space expansion is overcome by gravitational structures such as galaxies, and it not reshaping the universe on such small scales. It seems to me that if time is speeding up, it would have impact down to the subatomic level. Can anyone explain if the two ideas (space expansion vs time speeding up) are interchangeable? Question 2: Searching on the internet I found someone already proposing this idea: Jose Senovilla. Where does this man stand in mainstream science? Is he for real or far out? Is there anyone else working with this idea? Is there anyone creditable working with this idea? Summary: I am expecting that the idea of time speeding up over the life of the universe breaks down and falls apart at some point. Can anyone explaing to me what shoots down this line of thinking? Or maybe someone can tell me that it is a valid line of thought that is being considered in the mainstream?