Actually Mystech, it's not that absurd.
Ever heard of "Baked Alaska", where icecream is coated in a sugared eggwhite and then backed in an oven?
The understanding is that the eggwhite becomes flame retardant because of the heat fusing the coat into a hardened surface.
The same could quite easily occur to the extremities of a meteor during it's interaction with the friction of the atmosphere, not to forget that any object moving at speed creates a slipstream of pressure from postive at the direction it's moving to negative at the position it came from (which means only one side actuall fires up.)
Then there is the cold core of ice and dust, admittedly heat exchanges of this speed would cause the fragmentation of a rock (this is why most meteors brake when entering the atmosphere into small fragments).
Although the break point doesn't necessarily mean that any chunks speed up, some could actually slow because of the new resistance vectors of it's friction with the atmosphere.
As for Life forms existing within Meteors/Meteorites. non-complex organisms (Like worms, Bacteria) can survive being frozen and even have been thawed out to live again. I say "non-complex" but they are indeed complex, but there complexity is less in dimension as that of say a man, who's whole composition would be too complex just to freeze and then be thawed. Since freezing something of a larger volume means the freezing process occurs at different times throughout the volume creating potential damage from crystalisation.
It is suggested that potential building blocks (materials) were brought to this planet from a meteorite and interacted with other materials already here that triggered life and sustained it until now.
However I would disagree that SARS was caused by a meteorite. DNA is like an intelligence program, that constantly tries to "evolve" into something more efficent. It doesn't necessarily do it at great speed (In fact you could cross reference the life expectancy of a cell with that of some life expectancy of smaller mammals and find some relationship over how long it takes for a noticable evolution to occur)
However you have to imagine the number of animals from the same gene pool on this planet, all with their different life expectancies and different cell speeds, and you end up with the larges potential for mutations to occur. (If it was placed into a programming term, this would be a seriously large number of cycles)
When the mutation occurs it can travel like wildfire, spreading through families with the same genetic makeup who might individually have small differences. Then those small differences will be the similarity with someone else from a different genepool, to which the Virus then creates a new evolutionary stem.
Before you know it you have something thats not as containable as it once was, and the longer it's left the more uncontainable it becomes.
Hope that explains it all a bit better.
