The proximity of the sun protects the planet

An FMI study found that the proximity to the sun can provide protection to the planet's atmosphere.

The solar wind that blows as a continuous particle flow from the sun causes the loss into space of atmospheric elements from Mars and Venus because of these planets' lack of an internal magnetic field. The Earth's strong magnetic field prevents the direct impact of the solar wind on our own atmosphere. Mars and Venus have also lost almost all of their original water. The solar wind is a potential contributing factor to the dryness process.

More information:

Researcher Riku Järvinen, riku.jarvinen@fmi.fi

R. Järvinen, E. Kallio. Energization of planetary pickup ions in the solar system" ja se on julkaistu Journal of Geophysical Research: Planets Journal of Geophysical Research: Planets. Volume 119, Issue 1, pages 219–236, January 2014 (doi:10.1002/2013JE004534).

http://onlinelibrary.wiley.com/doi/10.1002/2013JE004534/abstract