Science Group Proposes No Warm, Wet Model For Mars Life
UPDATE: Early Mars and life there has been a heavily debated subject. However support for the following article was posted from Astrobiology Magazine on
(Thanks to Space.com)
Evolutionary life scientists who turned to Mars as the origin for life several years ago must now come up with new models to maintain their theories. Evolutionary scientists had to give up on their ideas that life originated on earth when it was determined there was not a sufficient time period on earth for evolution to occur; a fact to which many outside of scientific community have yet to wake up to. The earth had to be eliminated when it was determined that there was only a minimal time period for the evolution of life between the late solar system heavy bombardment, which ended 3.8 billion years ago, and the fossil record which now dates back 3.8 billion years. The late heavy bombardment is responsible for the huge craters we see on the moon, Mercury and Venus, and which have been found in the earth's crust. Evolutionary scientists had hoped the heavy bombardment did not extend out to Mars. Mars images show overflowing crater lakes and massive erosion with river valley like channeling. Great craters appear to have been overflowing and worn down by huge persistent rains (Mars as the origin for life was the theme behind the movie "Mission To Mars").
To maintain Mars as the origin for life, climate modelers must explain how the planet would have been any warmer in its early period 4 billion years ago then it is today. Today temperatures range from a high of -20 degrees Celsius in the temperate summer zones to frozen carbon dioxide (dry ice) zones at the poles. Climate modelers can not find the evidence they need for the green house gases necessary to secure the huge warmth needed from the faint Sun 228 million kilometers away. Evidence for early green house gases such as lime stone and methane is not present.
Science Magazine; 6 December, 2002. Now a group of physics-inclined planetary scientists have proposed a model that appears to account for what is seen on Mars today. Craters images now indicate the late heavy bombardment extended to Mars and was in fact heavier there than in the inner solar system. Twenty five of the largest craters range from 600 to 4000 kilometers in diameter. By comparison on Earth, the crater left by the impact that destroyed the dinosaurs 70 million years ago was170 kilometer in diameter. The Mars impacts had 1000 plus times the energy of the dinosaur killer impact.
Ejecta from great craters thawed frozen subsurface water creating scalding rains and flash flooding on Mars. Even the smaller impacts threw out hot vaporized material to cover the entire planet to an average depth of seven meters. Later after cooling a "matter rain" fell to cover the planets surface to a depth of two meters. Global surface temperatures reached 800 degrees K. Water every where including subsurface water was vaporized. Parts of the surface would have stayed above freezing for a year from smaller impacts, more than one hundred years for 250 kilometer impacts and for 1000 years plus for the large impacts. Planet wide sizzling rains followed.
Details are yet to be worked out, but most planetary scientists are acceptable that this fundamentally is the answer. Geologists concede the erosion but don't think there was enough water released for later valley formations. In any case it would have been a hellish wet environment turning to a cold, dry environment after the inner solar system sweep up the last of the debris from the solar system's formation.
Yet another group of scientists have provided new evidence that liquid carbon dioxide, not running water, may have been the primary cause of the erosional features. Research suggesting that condensed carbon dioxide found in Martian crust may have carved these features will appear this month in Geophysical Research Letters, published by the American Geophysical Union. Carbon dioxide is more volatile than water at lower temperatures, and the cold temperatures found on Mars would mean that less carbon dioxide-based magma would be required to produce the observed erosion than magma containing mainly water. The researchers suggest that this mechanism of erosion can also explain collapse features and channels elsewhere on Mars. They also note, however, that their model is based on a variety of assumptions that must be further tested. It should be noted that carbon dioxide can not exist on earth in liquid form due to the warm temperatures.
In any case, the volatile past on Mars has forced evolutionary life scientists to abandon the planet as the origin for life. No window for the time necessary for the evolution of life could have existed there as was the case on the earth.
Thanks to Reasons To Believe and Astronomy Magazine