© Lloyd, Charles Chandler

**Mike Fisher**'s theory at

http://newgeology.us seems to include the supposition that Earth's atmosphere was much thicker some millennia ago. The following supports that idea.

**DinosaurTheory.com:** To produce an effective buoyancy force on dinosaurs the Earth's atmosphere would have to be thick enough to have a density comparable to the density of water. By summing the forces acting on a typical dinosaur such as a Brachiosaurus the density of the necessary atmosphere is calculated as:

DF = DS (1 - 1/S.F.)

where DF is the density of the fluid, Ds is the density of the substance submerged in the fluid such as the dinosaur, and S.F is the scaling factor. Inserting into this equation a scaling factor of 3.2 and an overall vertebrate density of 970 kg/m3, the Earth's atmospheric density during the late Jurassic period can be calculated to be 670 kg/m3. This says that to produce the necessary buoyancy so that the dinosaurs could grow to their exceptional size, the density of the Earth's air near the Earth's surface would need to be 2/3's of the density of water.

**Robt Grubaugh** (I think) said, at the current rate of helium removal from the atmosphere, the atmosphere cannot be more than 30,000 years old.