Quote:
Originally Posted by xelasnave
Even if no trace of life on Mars it simply means we have not found anything on one planet..even if the signs are there we may not pick the right spot...and there are many more places to go both in our solar system and far far away.
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Ok .. I've been thinking about this … the formation of the oldest extant surfaces on Mars happened 4.5 to 3.5 Gya. More recent geologic activity, (ie: lava flows), and the formation of Olympus Mons happened about 2.9 to 3.3 Gya. Mars is thought to have been impacted by a Pluto sized planet about 4 Gya. There is evidence that plate tectonics existed at the same time. The soil on Mars contains magnesium, sodium, potassium and chloride all these are found in garden soil here on Earth. Trace water is present on Mars, and maybe even huge amounts flowed in the past. Mars' atmosphere is more than capable of
distributing surface based life (if it exists), as are the geological processes, and the movement of either frozen CO2, or water ice. There has been the same amount of time gone by to accomplish this same feat, as has happened for Earth.
On Earth, self replicating molecules are believed to have been produced about 4 Gya, and the last common ancestor of all life appeared about 3.5 Gya .. which is about the same time they think archaea also appeared (fossil record). The Moon was formed by the impact about 4.3 Gya. Water, ocean and atmospheric movements combined with plate tectonics and continental drift, have all played roles in distributing life evenly across the surface of the earth. Migration by species has obviously aided the distribution of life, also.
Both planets were subject to the same late-heavy bombardment 4.1 to 3.8 Gya.
My point here is that frankly, the composition of the environment, the atmosphere and geological history and age of Mars, is so similar to Earth's, (hence the life-distribution mechanisms are also similar), that if life is not
easily found on Mars, then I really do think there is a case to be answered, and some serious rethinking about theories on what causes life to emerge, in what we presently call the 'Habitable Zone'.
Frankly, Mars looks to be the best bet, (certainly in our lifetimes), for detecting life, given our present life-emergence theoretical guidelines.
An explanation is definitely called for, if the outcome of Curiosity's experiments is: "no life signs detected on Mars".
I will personally find it very difficult to accept:
- "oh .. we didn't look in the right spot" or;
- "oh .. we didn't look on the right planet (within the Solar System)";
as nothing more than nonsense answers.
Ideas about going to other places in the Solar System, (or far, far away), are completely useless without an over-riding theory whose goal is to refine the search field options .. from a parent population of astronomical proportions.
Cheers