Using Doppler shift, approaching light (future) is shifted towards blue, and receding light (past) is shifted towards red. Light at the present will have no shift and therefore neutral. So past will be red, future red and now any neutral colour.
Odd and interesting question. For me for some reason I would say greens and yellows for the past merging to autumn browns and reds for the present and then to white, grey and black for the future. Not too sure why I think this, but they certainly came immediately to mind.
Using Doppler shift, approaching light (future) is shifted towards blue, and receding light (past) is shifted towards red. Light at the present will have no shift and therefore neutral.
So past will be red, future red and now any neutral colour.
It was close as to who had the best answer. All are great and a good little community we have here. If u like my questions I have some very thought provoking ones.