So photons have momentum right? And stars are constantly expelling light on all directions, which eventually hits any object on its way and transfers a small amount of momentum. So wouldn't this constant 360°x360° transfer of momentum from all existing starts work as a constant expansion wave? Like constant explosions pushing everything around them away? I reckon it would be a very small amount of momentum transferred per star, but it would be almost constant, and it would come from every observable star, which could amount for enough momentum to cause the acceleration.
So, wouldn't the momentum transfer from the spherical expanding light of a star be causing the negative pressure we've been calling dark energy?