3 ms·

So 1 atom per cubic micrometer is about right for 0.1 microbar.

• TheSpiceIsLife 8y ago
  One cubic micrometer is 1mm³ right?
  • jonsen 8y ago
    One cubic micrometer is 1µm³. One cubic millimeter is 1mm³.
    • TheSpiceIsLife 8y ago
      Oh yeah, duh. Thanks.
• mirimir 8y ago
  Right, a cubic micrometer is 1E-18 cubic meter. So there are ~2.5 molecules per cubic micrometer at ~0.1 microbar.