A gas bearing (10) designed for instantaneous 5-10 micro inch separation at startup due to regulated entry and activation of rarefied molecular gas particles. The bearing has two opposing bearing faces (13, 21) with carefully matched geometries. One surface having grooves (15) with lands (16) formed between the grooves (15) that are designed for hydrodynamic operation. The other surface (21) is smooth such as an optically flat plane. The lift-off occurs at startup through the friction-energized gas molecules increasing their volume, and forcing the slowly rotating bearing faces apart. A precisely contoured leading edge (17A) is formed on each land (16) which sustains a negative molecular gas pressure in the slowly moving bearing interface, so as not to cause any unwarranted cooling or compression of the gas molecules until such speed is reached so that the normal pressurized gas bearing lift-off has been achieved, causing the gas compression flow to become unregulated and go normal.