Hi Harry,Love the blog, very informative, keep up the great work!Could we be in the beginnings of a extended solar minumum ("solar shutdown"), something that could last thousands, maybe millions of years? With the new models for how martian atmosphere has changed over the aeons coming out; I was wondering if the loss could be caused by a similar event, I tried to do some calculations using evaporation but was struggling to find density data. Still, I was thinking that the protons supplied by the solar wind are generally at a higher density than the air at about 100-200km abv sea lvl, and it seems probable that this flux changes the rate at which the lighter elements boil off, maybe even resulting in a net gain on some high intensity days. What if mars went through a similar lul, or perhaps began with an opposite event; a solar maxim giving it enough energy to have an atmosphere and liquid water, maybe even life! Thanks for the blog, would love to hear your thoughts.Regards,Shannon
Hiya Shannon - thanks for the compliment and the discussion. These are tough questions. It is now certain that solar activity over last half of 20th C was the strongest in 400 years (See Solanki, S in 'Nature' I think, last year); and that we are now in a deep minimum comparable with that of about 1880 (as the graph shows). Implications are not at all clear: tho' it's tempting to speculate.