[Red Badger]

“... an earlier atmosphere had about 35 percent oxygen compared to today’s 21 percent.”

That alone would make for a denser atmosphere. Oxygen has an Atomic weight of 15.9994 while Nitrogen is lighter at 14.000674.

Plus Oxygen is always O2, two atoms together, so a combined 32 approximately while Nitrogen is still at 14............................

[daniel1212]

That alone would make for a denser atmosphere. Oxygen has an Atomic weight of 15.9994 while Nitrogen is lighter at 14.000674.

That explains why I sometimes feel light headed.