[pedant mode on] Not to be difficult but this paper is from arXiv which opens up various questions. ArXiv is an archival electronic repository of scientific articles now hosted by Cornell University. According to Wiki they get 8,000 publications every month. And therein lies the problem. At that rate, it impossible to perform adequate peer review. Of course, some of these articles eventually will become published in proper peer reviewed journals, but the majority cannot. Peer review simply takes too long. I would just caution about anyone assuming that something from arXiv is the same as an article from the Astrophysical Journal. It does say that this paper is "under review" but I don't know what that means exactly.[pedant mode off]
As an interested layman, I do like that the article returns to the "we are all Martians" hypothesis. I have written about it before and for any one interested, it goes something like this:
1) The Earth and Mars are the same age.
2) Due to Earths greater size and mass, it remains in the Hadean phase longer than Mars
3) Condition favourable to life would occur earlier on Mars and primitive Archaea form on Mars first
4) Mars is next door to the Asteroid Belt and gets blasted by asteroids which fling pieces of Mars into outer space.
5) Some of these Martian fragments fall onto Earth. At this time, there are about 130+ meteorites that are known to be from Mars. Estimates indicate that tons of Martian material arrive on Earth every year.
link
6) These meteorites could have housed dormant bacteria or bio-molecules and could have seeded life here on Earth……so we are all Martians.
The article brings this up and mentions that the nucleic acids or the constituents that make up RNA and DNA are the ones that are the least susceptible to UV damage. For the author, this give a bolster to his general thesis of volcanic atmospheres filtering out more harmful radiation while allowing UV frequencies through, thus allowing life to form.
True……but wouldn't harsh conditions on Earth, which was also bathed in UV light, have selected for the most resilient forms of nucleic acids also? Here is a nice newspaper article, from a while back, explaining how RNA can form givin the correct conditions.
link
I would love the thesis presented in the above link to be true. I would even love it more to find out that an early Mars "seeded" life on Earth. I would love it as it makes for just one more great story, of the many, about how life has come about and changed.
Alas, right now, it is no more than a story. We still don't have good evidence that life ever existed on Mars. We may even be overlooking definitive evidence of that, as we don't know exactly everything to look for. But mostly, having viable bacteria surviving being blasted from the surface of Mars, remaining dormant when travelling through space, and surviving re-entry into Earth's atmosphere and then the impact on Earth, and then being able to colonize an alien planet………..well you get the picture.
gets his DNA results, and starts thinking about wargaming.
