The invaluable Planet Earth Magnetic Field–

Here’s an important bit of astrophysics that you can use to impress your friends–the early formation of a zircon based magnetic field protected the Earth from the Solar wind and allowed retention of atmosphere and such.

Fascinating. So many coincidences that created a friendly and safe planet to live on. Right now I can sit on my porch and not be afraid of getting zapped by cosmic rays or big hungry animals.

Mostly I have to worry about meddlers and nannies.

http://www.abc.net.au/science/articles/2015/07/31/4283843.htm

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4 responses to “The invaluable Planet Earth Magnetic Field–

  1. So many coincidences that created a friendly and safe planet to live on.

    With so many worlds and so much time, it seems inevitable that these coincidences will occur somewhere, sometime. I am not surprised that we find life on such a place.

  2. Reality Observer

    Rather misleading report, to be honest. Note that Venus has a much denser atmosphere than Earth – despite having no more core-generated magnetosphere than Mars does, and a far stronger solar wind to contend with.

    Now, I can accept a hypothesis that an atmosphere that permits a significant quantity of liquid water is not possible without a strong core-generated magnetosphere – but that is not what this team appear to be claiming; or they are being misquoted, perhaps.

  3. Reality–good points. I would be interested if you find some explanation for the Venus atmosphere–you are right, it at least raises questions about th assertions made.

    • Reality Observer

      I have not seen a paper on this – but there could quite easily be one behind a pay-wall that I have no access through.

      My best hypothesis is that it has to do with the proto-planet collision that formed the Earth-Moon system; that collision (if the theory there is correct, and it still looks very decent) would have stripped the majority of the early Earth atmosphere.

      There are reasonable side speculations on that theory (I’ve seen no conclusive evidence for those, however) that the collision also left Earth with rather more water than either Venus or Mars. Water dissociates quite nicely, unlike CO2, SO2, SO3, NO2, etc. So some more mass lost to hydrogen escape; plus the thinner lithosphere gives us tectonic turnover that neither of the other two planets still have – meaning more binding of the excess oxygen (and sulfur/nitrogen too, somewhat) in a continuous cycle, reducing the Earth atmospheric mass even more.

      Mars did indeed lose its primordial atmosphere, largely due to its much smaller gravitation – although undoubtedly it was also eroded by the solar wind mechanism noted by the authors of this paper.

      Really, the question here really is not why Venus has so much atmosphere – but why we have so little – little enough that life is supportable, but not so little that it isn’t.

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