• Question: to maintain and protect our earth we need the ozone layer, but how was it formed

    Asked by saneaah118 to Heather, Helen, Hugh, Jane, Julian on 11 Nov 2014.
    • Photo: Julian Onions

      Julian Onions answered on 11 Nov 2014:

      Its formed by the action of the suns rays on oxygen in the upper atmosphere. So initially the Earth didn’t have an ozone layer, but once bacteria and plants started making oxygen some of it made its way up to the upper atmosphere to be converted to ozone. So its continually being made, but isn’t particularly stable so some of it breaks down back to oxygen.
      Thus its in a sort of balance between being made and being destroyed.
      Some chemicals (now banned) cause it to break down faster, which was a concern for a while.

    • Photo: Hugh Osborn

      Hugh Osborn answered on 11 Nov 2014:

      We are lucky; any atmosphere with as much Oxygen as ours has should have an Ozone layer. This is because it forms when ultraviolet light (UV) from the Sun hits oxygen atoms. That UV, if it reached the surface, would be harmful to all of life. It could split up DNA molecules and cause lots of damage to cells.

      What is a more interesting question is where all the O2 in our atmosphere came from. Planets should not, on their own, have any oxygen. Instead, life created our atmosphere. Tiny, microscopic organisms that bloomed billions of years ago gradually turned water, sunlight and carbon dioxide into oxygen and organic molecules. Without that simple reaction, not only would we not have a protective ozone layer, but we wouldnt be here breathing oxygen at all.

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