life on Mars

As a boy I loved astronomy, and was into anything to do with space. I collected newspaper articles about the Viking expedition to Mars and pasted them in a scrapbook, alongside my own clumsy but fanciful drawings of what might lie on the red planet. The failure of Viking to find life on mars was a devastating blow to a young boy's fertile imagination.
Now, it seems, I was short-changed. The equipment used at the time to search for life would not have found it even even if life was there. Scientists have recently used the same equipment on Earth in places where bacterial life is known to exist. The equipment failed to find microbes even when the scientists knew that microbes were present. It turns out that microbes are too stable to be vaporised and detected in the manner that Viking tried to do.
There were three tests conducted by Viking to detect life. One of the three actually came back "positive" for life, but because the other two were negative, scientists disregarded the positive test. However, the man at NASA who was in charge of that "positive" test, Gil Levin, has always maintained that life exists on Mars. It was not a false positive, he says.
So is there life on Mars? As I have said before, I find the notion that bacteria live not only on Mars but other planets and non-stellar objects throughout the universe highly plausible.
In any case, even if there was not life before humans explored Mars, there is now, if you believe that humans are cyborgs. Two Mars rovers that landed there in 2004 are still roaming around the Martian landscape at the bidding of their human masters. If, as Andy Clark says, machines such as these are really an artificial extension of ourselves rather like a bionic limb, then there is a living human presence on Mars, in the form of two functioning robot explorers.