Empirical Earth · Gravity, Buoyancy & the Air

The atmosphere is an open system — no dome required

The claim

“Air can’t sit against vacuum without a dome, and leaking gas would be gone by now.”

What is measured

Earth loses ~90 tonnes of gas a day, almost all hydrogen and helium, out of a 5×10¹⁸ kg atmosphere. The bulk gases don’t escape at all; no wall is needed because gravity does the job. For the pressure and gas-law side, see gas next to vacuum.

What would show this is wrong

heavy gases (N₂/O₂) shown escaping at rates comparable to H and He, or a measured hard physical boundary, a “wall,” at the top of the atmosphere.

Sources

  1. NASA NSSDCA — Earth Fact Sheet. D. R. Williams, NASA Goddard Space Flight Center. nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html link
  2. Atmospheric escape — Jeans escape of hydrogen and helium. Escape is significant only when escape velocity < ~6× mean molecular speed; on Earth only for H and He. atmospheric escape link
  3. ESA Cluster — Earth’s leaking atmosphere (~90 tonnes/day). Steady polar-wind outflow of light ions; ~1 kg/s leaves the atmosphere, almost all hydrogen and helium. ESA: leaking atmosphere link
  4. Atmospheric retention, escape velocity & Titan’s atmosphere. A planet keeps a gas when escape velocity exceeds the gas’s thermal speed by ~6× (Jeans escape). Escape velocities: Moon 2.38, Me link
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