Why Are Galaxies Accelerating Away?

[frumenti]

If the rate of expansion of the universe is speeding up how could the expansion be caused by an explosion (Big Bang)? I know of no explanation for an explosion that gains energy over time.

 

[DaveC426913]

how could the expansion be caused by an explosion (Big Bang)?

It wasn't. The Big Bang was not an explosion. It was a rapid inflation. "Big Bang" was actually a term coined by its critics as a way to ridicule it.

 

[Johny Fake]

New to the forum. Could the gravitational time dilation (as opposed to dark matter) explain why the outer stars of a galaxy are able to travel at the high speeds. Essentially, they travel slower but have more time to make up the distance.

On a side note, how much empirical evidence is there for dark energy? If dark matter was proved to be an incorrect hypothesis, would dark energy be necessary? Could local gravitational fields at the more distant clusters be causing the changes in velocity?

 

[DaveC426913]

New to the forum. Could the gravitational time dilation (as opposed to dark matter) explain why the outer stars of a galaxy are able to travel at the high speeds. Essentially, they travel slower but have more time to make up the distance.

They have factored in relativistic effects, yes.