1. LIFE IN THE UNIVERSE LIFE IN THE UNIVERSE . . . . . . . The microbial evidences . . . . . . . The microbial evidences SPEAKER – SIDDHANTA MOHANTY GUIDE – Dr. B. Mittra SPEAKER – SIDDHANTA MOHANTY GUIDE – Dr. B. Mittra DEPT. OF BIOSCIENCE AND BIOTECHNOLOGY FAKIR MOHAN UNIVERSITY DEPT. OF BIOSCIENCE AND BIOTECHNOLOGY FAKIR MOHAN UNIVERSITY
2. CONTENTS 1. INTRODUCTION 2. RESEARCH EARLY LIFE ON EARTH EXTREMOPHILES SPORES POTENTIAL HABITATS SPACE BORNE ORGANIC MOLECULES DRAKE EQUATION EXTRA SOLAR PLANETS 3. EVIDENCES 4. STILL UNDER INVESTIGATION 5. LIMITATIONS 6. FUTURE MISSION 7. REFERENCES
3. INTRODUCTION Extraterrestrial life is defined as life that does not originate from Earth. Possible forms of extraterrestrial life range from simple bacteria-like organisms to more advanced than humans. It is unknown whether any such forms of life exist or ever existed. Panspermiais a theory that suggests that the seeds of life are prevalent throughout the Universe and life on Earth began by such seeds landing on Earth and propagating. Scientists are directly searching for unicellular life within the solar system, carrying out studies on the surface of Mars and examining meteors that have fallen to Earth. There is some limited evidence that microbial life might possibly exist in the universe.
4. RESEARCH EARLY LIFE ON EARTH Pre- Cambrianstromatolites in the Siyeh Formation, Glacier National Park. It is in formations such as this that 3.5 billion year old fossilized algae microbes, the earliest known life on earth, were discovered. The Precambrian fossil record indicates that life appeared soon after the Earth was formed. This would imply that life appeared within several hundred million years when conditions became favourable. Generally accepted scientific estimates of the age of the Earth place its formation at about 4.55 billion years old. The oldest known sedimentary rocks are somewhat altered Hadean formations from the southern tip of Akilia island, West Greenland. These rocks have been dated as no younger than 3.85 billion years.
5. EXTREMOPHILES Astrobiologists studying extremophiles as many organisms of this type are capable of surviving in environments similar to those known to exist on other planets. Some organisms have been shown to be more resistant to extreme conditions than previously recognized, and may be able to survive for very long periods of time. Some Bacteria and animals have been found to thrive in oceanic hydrothermal vents above 100 °C; a study revealed that a fraction of bacteria survive heating pulses up to 250°C in vacuum Recent experiments suggest that if bacteria were somehow sheltered from the radiation of space, perhaps inside a thick meteoroid or an icy comet, they could survive dormant for millions of years. Deinococcus radiodurans is a radioresistant bacterium that can survive high radiation levelsR
6. SPORES Spores are another potential vector for transporting life through inhospitable and inimical environments, such as the depths of interstellar space. Spores are produced as part of the normal life cycle of many plants, algae, fungi and some protozoan’s, and some bacteria produce endospores or cysts during times of stress. These structures may be highly resilient to ultraviolet and gamma radiation, desiccation, lysozyme , temperature, starvation and chemical disinfectants, while metabolically inactive. Spores germinate when favourable conditions are restored after exposure to conditions fatal to the parent organism.
7. POTENTIAL HABITATS FOR LIFE Some research suggest that there are many more potential habitats for life than Earth-like planets. The presence of past liquid water on Mars, suggested by river-like formations on the red planet, was confirmed by the Mars Exploration Rover missions. Water oceans might exist on Europa, Enceladus, iverse. Triton and perhaps other moons in the Solar system. Even moons that are now frozen ice balls might earlier have been melted internally by heat from radioactive rocky cores. Bodies like this may be extremely common throughout the Universe.
8. SPACEBORNE ORGANIC MOLECULES A 2008 analysis of 12C/13C isotopic ratios of organic compounds found in the Murchison meteorite indicates a non-terrestrial origin for these molecules rather than terrestrial contamination. Biologically relevant molecules so identified included uracil, an RNA nucleobase, and xanthine. These results demonstrate that many organic compounds which are components of life on Earth were already present in the early solar system and may have played a key role in life's origin. In August 2009, NASA scientists identified one of the fundamental chemical building-blocks of life (the amino acid glycine) in a comet for the first time.
9.
10. EXTRASOLAR PLANETS Astronomers also search for extrasolar planetsthat they believe would be conducive to life, such as Gliese 581 c, Gliese 581 g, Gliese 581 dand OGLE-2005-BLG-390Lb, which have been found to have Earth-like qualities.
11. EVIDENCES: 1976, THE VIKING MARS LANDERS DETECT CHEMICAL SIGNATURES INDICATIVE OF LIFE Tests performed on Martian soil samples by NASA's Viking landers hinted at chemical evidence of life. One experiment mixed soil with radioactive-carbon- labelled nutrients and then tested for the production of radioactive methane gas. The test reported a positive result.
12. 1996, MARTIAN "FOSSILS" ARE DISCOVERED IN METEORITE ALH84001 FROM ANTARCTICA NASA scientists announced in 1996 that they had found what appeared to be fossilized microbes in a potato-shaped lump of Martian rock. The meteorite was probably blasted off the surface of Mars in a collision, it was discovered in 1984 in Antarctica. Careful analysis revealed that the rock contained organic molecules and tiny specs of the mineral magnetite, sometimes found in Earth bacteria. Under the electron microscope, NASA researchers also claimed to have spotted signs of "nonbacteria".
13. 2001, MORE RIGOROUS CALCULATIONS CONNECTED TO THE 1960S "DRAKE EQUATION" SUGGESTS THAT OUR GALAXY MAY CONTAIN HUNDREDS OF THOUSANDS OF LIFE-BEARING PLANETS The Drake equation multiplies together seven factors including: the formation rate of stars like our Sun, the fraction of Earth-like planets and the fraction of those on which life develops. Many of these figures are open to wide debate, but Drake himself estimates the final number of communicating civilizations in the galaxy to be about 10,000.
14. 2004, METHANE IN THE MARTIAN ATMOSPHERE HINTS AT MICROBIAL METABOLISM In 2004 three groups - using telescopes on Earth and the European Space Agency's Mars Express orbiting space probe - independently turned up evidence of methane in the atmosphere. Nearly all methane in our own atmosphere is produced by bacteria and other life.
15. 19 May 1995: two scientists at Cal Poly showed that bacteria can survive without any metabolism for at least 25 million years; probably they are immortal. 24 November 1995: The New York Times described bacteria that can survive radiation much stronger than any that Earth has ever experienced. 7 August 1996: NASA announced fossilized evidence of ancient life in meteorite ALH 84001 from Mars. 27 October 1996: geneticists showed evidence that many genes are much older than the fossil record would indicate. Subsequent studies have strengthened this finding. 29 July 1997: a NASA scientist announced evidence of fossilized microscopic life forms in a meteorite not from any known planet. 1998: a microfossil that was found in a meteorite and photographed in 1966, was recognized by a Russian microbiologist as a magneto tactic bacterium. h
16. 26 April 2000: the German team operating the mass spectrometer on NASA's Stardust mission announced the detection of very large organic molecules in space. 19 October 2000, a team of biologists and a geologist announced the revival of bacteria that are 250 million years old, strengthening that case that bacterial spores can be immortal. 13 December 2000: a NASA team demonstrated that the magnetosomes in Mars meteorite ALH 84001 are biological. 2 August 2004: Very convincing photos of fossilized cyanobacteria in a meteorite were reported by a NASA scientist.
17. STILL UNDER INVESTIGATION On May 11, 2001, two researchers from the University of Naples claimed to have found live extraterrestrial bacteria inside a meteorite. An Indian and British team of researchers led by Chandra Wickramasinghe reported on 2001 that air samples over Hyderabad, India, gathered from the stratosphere by the Indian Space Research Organization contained clumps of living cells In 2005 an improved experiment was conducted by ISRO. On April 10, 2005 air samples were collected from six places at different altitudes from the earth ranging from 20 km to more than 40 km. three new species showed that they were more resistant to UV radiation than similar bacteria found on Earth. new species and named Janibacter hoyeli.sp.nov (after Fred Hoyle), Bacillus isronensis.sp.nov(named after ISRO) and Bacillus aryabhati(named after the ancient Indian mathematician, Aryabhata).
18. LIMITATIONS Life as we know it requires the elements hydrogen, carbon, nitrogen, oxygen, iron, phosphorus and sulfur (H, C, N, O, Fe, P and S respectively) to exist at sufficient densities and temperatures for the chemical reactions between them to occur. These conditions are not widespread in the Universe, so this limits the distribution of life as an ongoing process Space is a damaging environment for life, as it would be exposed to radiation, cosmic rays and stellar winds. Environments may exist within meteors or comets that are somewhat shielded from these hazards. However, the extreme resistance of Deinococcus radiodurans to radiation, cold, dehydration and vacuum shows that at least one known organism is capable of surviving the hazards of space without need for special protection.
19. FUTURE MISSION The 'Living Interplanetary Flight Experiment' The Living Interplanetary Flight Experiment, which is being developed by the Planetary Society, will consist of sending selected microorganisms on a three-year interplanetary round-trip in a small capsule aboard the Russian Phobos-Grunt spacecraft in 2011. The goal is to test whether organisms can survive a few years in deep space. The experiment will test one aspect of transpermia, the hypothesis that life could survive space travel, if protected inside rocks blasted by impact off one planet to land on another. CONCLUSION There are so many evidences and limitations also. So, more and more research need for strong evidences to prove the life existence throught the universe.
20. REFERENCES Mautner, M; Matloff, G. (1979). "Directed panspermia: A technical evaluation of seeding nearby solar systems.". J. British Interplanetary Soc.32: 419 Mautner, M. N. (1997). "“Directed panspermia. 3. Strategies and motivation for seeding star-forming clouds”". J. British Interplanetary Soc.50: 93 Margaret O'Leary (2008) Anaxagoras and the Origin of Panspermia Theory, iUniverse publishing Group, # ISBN 978-0-595-49596-2 Berzelius (1799-1848), J. J.. Analysis of the Alais meteorite and implications about life in other worlds. "LIFE IN SPACE FOR LIFE ON EARTH - BiosateliteFoton M3". June 26, 2008. http://www.congrex.nl/08a09/Sessions/26-06%20Session%202a.htm. Retrieved 2009-10-13.
21. "Uplift and Outflow of Bacterial Spores via Electric Field". Adsabs.harvard.edu. 2006-07-23. http://adsabs.harvard.edu/abs/2006cosp...36....1D. Retrieved 2009-08-20. Studies Focus On Spacecraft Sterilization European Space Agency: Dry heat sterilisation process to high temperatures Schidlowski, M. (May 1988). "A 3,800-Million-Year Isotopic Record Of Life From Carbon In Sedimentary-Rocks.". Nature333 (6171): 313-318. doi:10.1038/333313a0. Gilmour I, Wright I, Wright J 'Origins of Earth and Life', The Open University, 1997, ISBN 0-7492-8182-0
