well theres a few points to this:
how dark is it? If it's night time and you can only just make out a silhouette, then the orange has no colour, because for it to have colour it would have to be subjected to light, (white light or a light that carries a colour that the orange reflects)
Since Orange is a mixture of Red and Yellow, the light sources it could reflect are White light (which in the dark wouldn't be existant), or it could be Infra-Red which is present at night from the fluctuation of free floating atoms and molecules.
Of course infra-red is just before the eyes visual spectrum, otherwise we would be able to see at night.
Green would be within our visual spectrum of light and wouldn't occur at night (of course I'm going ont he assumption that it's pitch black)
The questions you could then ask are:
Is the orange moving? If so is it moving away or towards you?
I mention this because in normal light if something is travelling towards you, it has a higher frequency of light stemming up to ultraviolet, while if it's travelling away it will be more towards the infra-red end of the scale.
Of course you wouldn't be able to notice this unless you used particular types of equipment like a Spectrophotonmeter.
This would mean also that if the orange was travelling towards you (or you towards it) it might have a perception of green.
Of course I can't apply the speed you need to be approaching the orange, or the orange approaching you.