Just as numerous Martian rocks and fossils were displaced into the space and formed the Asteroid Belt and meteorites (
Edit [Moderator]: Link removed ), a portion of the water on Mars were displaced into the space and formed dirty ice around comets. The theory goes as follows:
1. When heavy rocks/fossils could somehow be moved to the space to form the asteroid belt, it is not strange that water could also be displaced together with solid sediments into the space and formed dirty ice of comets.
2. There are quite a few meteorites that came from comets. Those meteorites have been found to contain fossilized cells of Martian origin (note 1).
So, the dirty ice around the comets should have also originated from Mars.
Note 1: The following articles describe meteorites coming from comets and containing Martian fossils:
1. 1. http://journalofcosmology.com/Life100.html
2.
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3.
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4.
http://arxiv.org/ftp/arxiv/papers/1104/1104.1314.pdf
5.
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