If you've ever wondered why the air seems thinner at either of Earth's poles, then the answer may have something to do with our planet's magnetic field, and the fact that it just may be stealing our oxygen.
Swedish scientist Stas Barabash (of the Swedish Institute of Space Physics), believes that comparing the amount of escaping ions from Venus (which has no magnetosphere), Mars (which used to have one, but no longer) and Earth proves that our magnetic field may be accidentally helping our oxygen ions to abandon us, writes New Scientist:
Taking into account the different masses of the three planets, their atmospheric make-up and their distance from the sun, Barabash compared the rate of loss of oxygen ions from each one. He focused on oxygen ions because these are the most abundant ions in the ionospheres of all three planets. He found that Earth lost oxygen around three times as fast as the other planets.
Barabash points out that a planet's magnetosphere will always be far larger than the planet itself or its atmosphere. This, he reasons, means that a planet with a magnetic field will absorb more energy from the solar wind than it would if it didn't have one. This extra energy would be funnelled down towards the magnetic poles, so molecules in the ionosphere above these regions could be accelerated enough to escape (see diagram). Barabash presented the results this month at the International Conference on Comparative Planetology at Noordwijk in the Netherlands.
Don't get too worried about running out of air to breathe, however; Barabash estimates that we're only losing about 60,000 tonnes of gas each year from an overall total of "thousands of trillions of tonnes."
Earth's protective shield is stealing our air [New Scientist]