I just have great difficulty thinking either Earth or Mars, or indeed our solar system, is a closed-system. We have evidence for material transfer to Earth and I see no reason to think ejecta from Earth could not reach Mars. I imagine by the time we begin colonising Mars the idea of cosmic ancestry will be commonplace and walking fields looking for earthly meteorites will be routine science.
Originally Posted by antoniseb
This incident raises another question for me: If they're really trying to find evidence for an independent abiogenesis event why would project managers make such a decision? It doesn't seem so much a "slip up" as it seems purposeful.
I *do* think we need to be extremely careful about Europa, Enceladus, and other more likely places for life. Following good procedures is important. Your above mentioned MSL slip-up is evidence that we're not ready to launch to more likely life places.
Where the telescope ends, the microscope begins. Which of the two has the greater view?