Imagine a balloon with nothing in it except two masses M1 and M2, like first drawing. The gas of atmosphere apply a force to move up Fgas, and the weight apply a force to move down Fm1+2. Weight of M1+M2 is equal to the force from gas (opposite direction). Now, rotate M1 and M2, like that the weight is lower because gravity is a law like 1/d². Fgas>Fm1+2. The balloon attrack Earth to up ? I though it was the diametrical atmosphere (where balloon would be) but we can put a second balloon too without rotate masses (like second drawing). So, can you explain how forces works on Earth ?