lew (04/11/83)
The equation for the pressure of an isothermal gas in a linearly increasing gravitational field is: p(z) = p1 * exp( -(mg/kT) * 1/2 * z^2/R ) Here p1 is the pressure at z=0, and g is the g-field value at z=R. This equation is derived just like the exponential atmosphere equation: p(z) = p0 * exp( -(mg/kT) * z ) The value of kT/mg is the height of a column of atmospheric density that is supported by atmospheric pressure in a uniform gravitational field with value g, that is 8km; mg is the average weight of an air molecule. In the first equation, we require that p(R) = 1 atm, or: p0 = p1 * exp( -R/16km ) ; p1 = p0 * exp( 400 ) !!!!!!!!!!! Obviously, the ideal gas law will fail before these conditions are even approached. Never mind though, the tunnel would collapse anyway! Lew Mammel, Jr. ihuxr!lew