[Red Badger]

Of course it has, but its dark side would be lightly ‘illuminated’ by reflected light from Jupiter if the moon is in between the Sun and Jupiter.........................

[hanamizu]

Of course it has a dark side, but it doesn’t have a side that is in permanent darkness. No one talks of the dark side of earth when it’s nighttime. But people do refer to the ‘dark side’ of the moon when they really mean the far side of the moon, the part we never see because our moon is tidally locked so we only see one side. Of course both sides get sunlight as the moon revolves around the earth.

I would image the side of Ganymede facing Jupiter would quite a bit of light bounced back from Jupiter.