> While this in itself does not invalidate the actual math in the paper, which is fine Actually, on going back and re-reading, I realized that even the math in

> While this in itself does not invalidate the actual math in the paper, which is fine Actually, on going back and re-reading, I realized that even the math in the paper has an error. The formula for buoyancy force is wrong! Rovelli's formula for buoyancy force is V rho (in the upwards vertical direction), where rho is the density of the fluid in which the object is immersed. But this is wrong; it doesn't even have the right units. This formula says that the buoyancy force is equal to the mass of the displaced fluid; but mass is not force. The correct formula is V rho g, where g is the acceleration due to gravity; in other words, the buoyancy force is equal to the weight of the displaced fluid. (To check against your intuition, you can plug in numbers and realize that, according to Rovelli's formula, an ordinary helium balloon of the kind you get for birthday parties would not rise in air!) This just makes the paper even more disappointing.