Friday, March 15, 2013

Mars: Analyzing Layers of History - 4

Gale Crater on Mars formed by impact.
In the previous post in this series we discussed a rumor about a major discovery on Mars that did not pan out.

But, last Tuesday NASA informed us of the results from the first drilling exercise ever by any human-made robot exploring another planet.

The Curiosity Rover, in Gale Crater on Mars, drilled into a rock to see what history the inside of the rock could reveal.

It was one for the history books, a major scientific discovery.

One of the science team leaders said that there was drinkable water there when the rock was formed, and biological life could have existed there:
An analysis of a rock sample collected by NASA's Curiosity rover shows ancient Mars could have supported living microbes.

Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon -- some of the key chemical ingredients for life -- in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet last month.

"A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington. "From what we know now, the answer is yes."
(NASA Curiousity Rover, emphasis added, see video below). Today, let's concern ourselves with what they did not say, but what is obvious from the context.

The graphic portrayal of an asteroid crashing into Mars to form Gale Crater, depicted at the top of today's post, is the main historical consideration.

We discussed the geology and topography of Gale Crater earlier in the series (Mars: Analyzing Layers of History).

But the finding by NASA that clean, potable water was abundant after the catastrophe that created Gale Crater is what I want to talk about today.

Because it means that Mars had robust life at the time of the impact, robust biological life.


Because clean water flowing eons after a catastrophe like that would be very similar to what happened on Earth to form Chicxulub:
A panel of 41 international experts, including UK researchers from Imperial College London, the University of Cambridge, University College London and the Open University, reviewed 20 years' worth of research to determine the cause of the Cretaceous-Tertiary (KT) extinction, which happened around 65 million years ago. The extinction wiped out more than half of all species on the planet, including the dinosaurs, bird-like pterosaurs and large marine reptiles, clearing the way for mammals to become the dominant species on Earth.

The new review of the evidence shows that the extinction was caused by a massive asteroid slamming into Earth at Chicxulub (pronounced chick-shoo-loob) in Mexico. The asteroid, which was around 15 kilometres wide, is believed to have hit Earth with a force one billion times more powerful than the atomic bomb at Hiroshima. It would have blasted material at high velocity into the atmosphere, triggering a chain of events that caused a global winter, wiping out much of life on Earth in a matter of days.
(From Deepwater I To Deepwater II). Something similar must have happened on Mars at Gale Crater, since such a large crater was formed.

Life anywhere near the impact site would have been vaporized, and a mass extinction would have begun.

But then, the abundant water of Mars came back into play over vast amounts of time, and eventually covered and filled Gale Crater.

Later, over time water and wind eroded it back to its condition and appearance today (see Cosmic Rosetta Stones?).

It would have taken a very long time, but the NASA space rover with a laboratory of tools has discovered that Mars survived the impact, and clean water flowed again, after the impact, for a long time at Gale Crater.

Some astronomers think that a water-world type planet existed between Mars and Jupiter, that it exploded for some reason (failed Dyson Grid?), and that nearby catastrophe caused damage which removed life from Mars over a long span of time (see e.g. Weekend Rebel Science Excursion - 7, Weekend Rebel Science Excursion - 11, and Exploded Planet Hypothesis).

Hope we find some microbes or fossils next.

The previous post in this series is here.

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