Life on Mars the 16

Life on Mars

The 16 August issue of the Science magazine published an article by a group of scientists led by David Mckay on the discovery of evidence of primitive bacterial life on Mars. This article is based on the examination of a meteorite found in Antarctica and supposed to be from the planet Mars. The reasons to publish such an article were 1) the presence of hydrocarbon similar to breakdown products of dead organisms on Earth, 2) Mineral phases considered to be byproducts of active bacteria and 3) carbonate globules of tiny size, which could be microfossils of primitive bacteria. All these were found in a very small diameter distance. A chronology of dates dating back to about 4.5 billion years gives details about the meteorite, which was ALH84001, which was found in the Allan Hills region of Antarctica in 1984. The chronology of events begins with the original solidification of the igneous rock, the fracture of the rock by meteorite impacts, the deposition of carbonate minerals that allowed primitive bacteria to live in the fractures and the dislodging of a major chunk of the rock which was later ejected to the space. The evidence for life on Mars is found from mineralized fractures in the meteorite found in close proximity. The discovery of plenty of polycyclic aromatic hydrocarbons on the surface of fractures which are complex organic molecules generally formed by non-biological factors. The evidence from meteorite ALH84001 suggests possibility of biological origin. (Williams, 2005)

Carol Stroker and Larry Lemke explained to a group of space officials that they have identified strong evidence about the existence of life on Mars these times in hidden caves that are sustained by Water. The report was based on methane signatures and other signs of possible biological activity that was similar to those discovered in the caves on Earth recently. The scientists at NASA are involved in research and have theorized Martian subsurface that it could shelter biological organisms which have developed unusual abilities to exist in extreme conditions. This lead Stroker and a group of U.S. And Spanish researchers to search for subsurface life near the Rio Tinto River called so because of its red tint caused by highly acidic water which dissolves iron. The main aim of the search was to unravel underground microbial ecosystem that might control the chemistry of the environment on the surface. Similar search for life in the Mars may have coincidental effect to that of the search in Rio Tinto to uncover a novel uncharacterized metabolic strategy living in the subsurface. Stroker said that by comparing their search in Rio Tinto with the details collected by ground-based telescope and orbiting space craft have reached conclusions that life exists below the subsurface of Mars. The scientists pointed out that fluctuating methane signatures could be the presence of active underground biosphere and the presence of sulfate jarosite a mineral salt present in Earth in hot springs. NASA is now planning to send a powerful rover to Mars in 2009 to sniff out methane with high sensitivity to further throw light on the findings. (Berger, 2005)

There is a speculation as a result of findings from the meteorite ALH84001 that life could have existed in Mars. An analysis of satellite images has given evidence on the presence of extremophiles on Mars. The biological origin accounts to annual appearance and disappearance of dark dune spots at the polar regions of the planet. Another evidence to prove the existence of life on Mars is the presence of Haloarchaea, which could live on Mars since the atmosphere of Mars has a pressure that is below the triple point of water where freshwater species annot exist. Thus the Mars Exploration Rovers of 2004 focussed to find an evidence of liquid water than to find present or past life on Mars. In the year 2004, it was announced by NASA that the rover Opportunity had found evidence that Mars was a wet planet in the past which gave hope of past life on the planet. However, in December 2006, the images taken by Mars Global Surveyor showed that there was flow of water on the surface of the planet occasionally which was characteriesed by the changes in craters and sediments. The presence of water on Mars was analysed to find possible life on the planet at present or in the past. (Wikipedia, 2007)

The Viking experiment was conducted to find more evidence of life on earth. The Viking landers were sent to Mars in the 1970's to detect organic substance and the presence of organisms of Martian surface. The evidence form Viking experiment gave mixed results. While one experiment found no evidence of organic compounds in the soil other experiment gave positive results. A test conducted by dropping nutrient solution gave immediate positive result. It was concluded that the result was due to the presence of oxides in the soil. Dr. Gilber Levin conducted these experiments and he was convinced that there is life on Mars. Since the debate continues for the evidence for life on Mars, it may be concluded that a trained field geologist with a rock hammer may be send for a human on site exploration for a much better chance of finding evidence of life. A Human to Mars program may be organized as per the opinion of the Mars society. ("ALH84001 - the Life on Mars meteorite," n. d.) telescopic study of Mars in the late 1890 spawned theories on vegetative and a possible intelligent life on Mars. Though this was a popular idea, the poor quality of the data made it plausible. As per their study the poles of Mars were ice locked and it seemed to hold the possible essential matter for life H2O. The question which later arose was the presence of H2O in liquid form. Even till the year 1962, astronomers interpreted the theories that said there was life on Mars. It was studied through spectroscopic date that there were vegetations on the surface of earth. All the above were held good until Mariner 4, the first spacecraft transmitted photographs that showered craters without any sign of considerable vegetation which also measure the atmosphere and temperature that revealed the characteristic of Mars was not suitable for most creatures on Earth. Although certain experiments revealed primitive forms of life on Earth could survive under specific Martian conditions for some time period. The evidence later given by Mariner 6 and 7 gave the information that the atmosphere of Mars was mainly made of Carbon Dioxide. In 1970, all earlier perception gave way to a theory of Mars being lifeless and unsuitable for life which was very much in contrast as considered before. ("Life on Mars - past and present," n. d.)