So I had some fun with Pb. Now that it is in the center of the Earth, the magnetosphere is just a touch stronger.
Lets look at that He balloon. We are going to use the large rubber red balloon and fill it with 5kg of He. Naturally it also has some natural air gasses in the balloon before we filled it. Those sink to the bottom. We let them out and tie off the balloon.
Now I let go of the balloon. As it rises, more radiation from the Sun hits the balloon. This allows He to escape and continue its ascent. When the helium inside the balloon has less mass then the rubber balloon, the balloon will sink. But the He continues to rise to the level of its density.
If we change the material of the balloon to Mylar it would be months or years before the Helium could escape. I know, there is a birthday balloon around here that is older than some of my birds.
This floating Mylar balloon should not occur. It has a mass of 5kg + the mass of the balloon. Yet it rises. It can only rise the average of the densities.
This should not happen with gravity. The balloon has mass. Its mass is less than the earth. So it should drop to the ground at Gm1m2/r^2. This is not what the data shows. The balloon rises. Sorry guys. There is no Graviton.