I went outside to move car into our driveway. Looked south at our cat on the fence and my attention was drawn to two very bright red lights traveling slowly but steadily from the south in a NNW direction. I watched them for 10 seconds or so before running inside to get my wife and two daughters to have a look to validate what I was looking at. The orb like structures seemed to radiate or glow a bright red colour and they made no sound whatsoever as they moved across the sky.My initial thought was they were satellites as they had the same constant speed observed of satellites on clear nights. I then realised that the sky was very cloudy and that these lights were below the cloud cover. This was proven when the western most light began to gradually be obscured by clouds before disappearing entirely. The other light followed it behind clouds shortly after. Both lights could be seen gradually disappearing behind the clouds over a period of a couple of seconds and showed that they were emitting their own light. Despite scanning the clouds in the area I was unable to see the lights reappear. There was probably 80% cloud cover on the night.There is an airstrip in Ballarat the services small planes and I am very familiar with the sight and sound of these planes. We also have a hospital that occasionally flies helicopters to Melbourne so am also familiar with lights and sounds associated with these. These lights were neither.The distance between them, though impossible to accurately guess, would have meant that it would have to be a very large plane between the two orbs and it would've had to be flying very low and silently. As I watched the lights gradually disappear behind the cloud cover there was no structure observed anywhere associated with the orbs. They appeared to be completely independent of each other however flying in absolute unison.I'm a scientist and can offer no logical explanation for this sighting.