Yes all dogs do eventually get tired of barking and will shut up.
A dog can bark at the slightest of things and may hear and see things that humans cannot.
So if your dog is barking constantly and you don't see or hear anything it could be that something is farther off in the distance and you cannot hear it or see it but the dog can at least hear it.
It could be as simple as a squirrel or they could be hearing other animals off in the distance.
However if your dog is barking constantly then you could get into trouble if there is a noise ordinance in your area so you should try to stop the dog barking at night and bring the dog inside your house if possible.
It's not nice for neighbors to have to hear someone's dog barking constantly either in the day or at night.