A new picture of the composition of comets is emerging with the help of 21st century technology available at Diamond, the UK's national synchrotron light source, in Oxfordshire.
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©NASA/JPL
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Comet Wild 2.
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Scientists already know that comets played a significant role in ensuring that conditions were right for life on Earth. Most of the icy, small planetary bodies that otherwise became comets went into forming the gas giant planets in the outer Solar System but some were ejected from the vicinity of the largest planets. Of these, a fraction ended up in the inner Solar System bringing water and biogenic elements of interest to Earth. Without this cometary transport, life on Earth may never have had a chance to start.
Now, scientists from the Space Research Centre at the University of Leicester have, for the first time, brought samples of the Comet Wild-2 to Diamond. In doing so, using Diamond's microfocus spectroscopy capabilities - bright and powerful X-rays with a beam size equivalent to one 25th of a human hair - they have discovered that the old model of comets as dusty iceballs is not the whole picture.