As we all know, in short, Dark Energy is the name given to the observed effect of the expansion of the universe accelerating. However there is only one method of observing this, which is to see that the furthest galaxies away from us appear to be moving away from us faster than closer ones.The expansion of the universe is not measurable on smaller scales such as within our solar system or galactic cluster. The proposed explanation for this is that gravity can still overcome Dark Energy on these scales.

However, there is no Dark Energy. There is in fact a very simple explanation for this effect, and that is that the photon has mass. Negligible mass, the tiniest mass possible, but mass nonetheless.

From the detection of gravitational waves we know that the most massive objects in the universe send ripples through space-time as they move. Currently our detectors are only able to detect enormous waves from these enormous objects. But there is no reason that all objects could not also produce these waves, with the smallest objects producing waves too tiny for us to detect.

This then explains the red shift of the most distant galaxies and why we only see the effects of "dark energy" on the largest scales. It is in fact the photons losing energy to space-time itself as they travel, losing it in such tiny amounts that we only notice its effect on the largest scales possible.