Did meteorites bring life from Mars?
Posted 01 October 2013 - 05:36 PM
Posted 02 October 2013 - 11:57 PM
The idea here is not that Martian meteorites contained some sort of biological spores or living material that brought life here.
Instead, Martian meteorites contained key chemical ingredients that allowed the formation of RNA, a critical stepping-stone on the way to the evolution of life. At the time, Earth lacked the right conditions and ingredients to form RNA, and it is theorized that the source of the missing ingredients could be Martian meteorites.
It is a tantalizing theory not without merit. But, the evidence is far from conclusive.
It's entirely possible though. We may have a simple shower of Mars rocks to thank for our existence.
I'm not sure what merit it has. I've not seen any evidence that early Earth had any particular inability to support the synthesis of RNA, or that early Mars had any special ability to. If anything, early earth should have had access to pretty much any environmental condition that early Mars would have, plus others as well.
All we have on either side of that particular issue, so far as I know, are speculations. I'm pretty dubious about anyone who thinks he can turn those into assertions.
You are exactly right. There is no reason to believe the odds of a meteor bringing life to Earth is more probable than RNA world hypothesis in action here. Everything was in place, and for those who are not aware of RNA world and the interaction between silicate clays, water, and self reproducing molecules, I suggest you research it for yourself. Since Earth was formed by the accretion of dust and gas during Sol system's formation, where is the line drawn in regards to panspermia? After the late bombardment? After the Great oxygenation event? There have been several mass extinctions, yet all life uses the same genetic code, with the same chirality in amino acids, I would love to delve into the topic of why it is more reasonable to assume that RNA world has more validity, but some people do not want to accept it, so I will not waste time. I can say I am glad someone rationally commented , and I am glad somebody gets it.