After finding out that Earth is not a planet
(it didn't clear out its orbit...), I now learned that Earth's doesn't have life on it. Sounds strange? Well, Navarro-González et la., in a recent paper
that appeared in PNAS, showed that the same tests used on the Viking program and that came out negative for life on Mars, showed negative results also in the Antarctic Dry Valleys and the Atacama and Libyan deserts.
Specifically, these authors demonstrated that the Viking Lander thermal volatilization (TV)-gas chromatography (GC)-MS experiments are insensitive to the amount of organic material found in the aforementioned locations on Earth. True, life is not teeming over there, but who said it was on Mars. The bothering point, however, raised by these authors is that "the TV-GC-MS is still considered the standard method for organic detection on future Mars missions"
... something to think about (and correct).