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How much mass does the solar wind add to the earth in a year?
With streams of protons from the sun being pulled in at the poles by earth's magnetic field, I was just wondering how much mass that would add to the earth in a year?
ok, i've had a go at working this out myself...
If we assume that whatever particles coming right at earth hit us (I know some are deflected - as i understand it half are pushed one way along the magnetic field lines and half the other way, but the magnetic field also "scoops up" particles from a larger area than a cross-section of the earth, so lets say it evens out)...
...so, I looked up what fraction of light hits earth - from different sources the figure given seemed to vary from 4.5x10^(-10) to 7.2x10^(-10)... using figures on a nasa webpage I got 4.7x10^(-10), so guess I'll use that [conservative] figure...
then I looked up how much mass the sun gives out via the solar wind each second - a discussion on wikipedia about it suggests it is 6x10^8 kg/sec...
so in a year the mass given out in the solar wind would be...
6x10^8 x 60 x 60 x 24 x365.25 = 1.89x10^16 kg/year
...and the fraction hitting earth would be...
1.89x10^16 x 4.7x10^(-10) = 8.9x10^6 kg/year or 9000 tonnes
that's comparable to the 37,000-78,000 tons of meteorites that land each year according to this: http://curious.astro.cornell.edu/question.php?numb...
3 Answers
- MorningfoxLv 710 years agoFavourite answer
"Negligible" isn't very informative, is it? I calculated an actual number, and I got about 0.13 kg per year, or maybe 0.30 kg (11 ounces) in a very active year.
- Roger KLv 710 years ago
There is a lot more mass added because of cosmic dust raining down on the earth. Don't know the exact quantity, but I seem to recall dust accounts for many tons of additional mass each year. Even that is inconsequential when compared to the existing mass.
