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Meteor Crater
Approximately 50,000 years ago a huge iron-nickel meteorite 150 feet in diameter and weighing 100,000 tons crashed into the Colorado Plateau of northeastern Arizona. Traveling at 26,000 miles per hour, it struck the plateau with an explosive force greater than 20 million tons of TNT. In less than a few seconds, a crater 700 feet deep and over 4,000 feet across was carved into this once-flat rocky plain.

Massive Meteor Crater, Arizona

Although it is only 14 inches in length, you probably need both hands to hold this meteorite. It is for sale at Jim Gray's Petrified Wood Co. in Holbrook, Arizona for a mere $12,000.

43. Building Blocks Of DNA From Outer Space?

  From Wayne's Word Evolution Page  

One of the most interesting pieces of evidence for an extraterrestrial origin of complex biological molecules is the discovery of DNA bases (nucleobases) in carbon-rich meteorites (carbonaceous chondrites) from Antarctica. According to Dr. Michael Callahan of NASA's Goddard Space Flight Center (2011): "For the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually were created in space." Callahan is lead author of a paper on the discovery appearing in Proceedings of the National Academy of Sciences, 2011. Extracts from carbon-rich meteorites were analyzed by liquid chromatography and mass spectrometry to determinine the chemical compounds and their stuctural formulas. Adenine and guanine, two of the four DNA bases of life, were isolated plus a variety of nucleobase analogs not found in living organisms. These nucleobase analogs are important because they would not be expected from terrestrial contamination. In fact, none of them were found in the nearby ice. The well-studied Murchison meteorite in Australia also contained nucleobase analogs and over 100 amino acids (Zita Martins, et al. 2008). These nucleobases were synthesized in non-biological reactions in the laboratory from chemicals present in asteroids, including hydrogen cyanide, ammonia and water. According to N. Lane, J. Allen and W. Martin (2010), the presence of complex biological molecules in meteorites does not mean that life must have arisen in outer space.

Meteorite fragment from Arizona and illustration of 4 DNA nucleobases: Adenine (C5H5N5), thymine (C5H6N2O2), cytosine (C4H5N3O) and guanine (C5H5N5O). In The above image, the pyrimidine base thymine has 2 red oxygen atoms. The purine base adenine has no oxygens. You can figure out the other 2 bases. For those counting atoms in the above molecules, each one is missing one green hydrogen because it is on the reverse side and not visible. Two purine bases, adenine and guanine, were found in carbon-rich Antarctic meteorites plus a variety of nucleobase analogs. If complex biological molecules were formed in space, were the building blocks for life on earth seeded from meteorites? It is intriguing to ponder DNA nucleobases (the rungs of DNA ladders) traveling through space inside meteorites!

Simplified model of a small section of ladder-shaped DNA. The "rungs" are composed of nucleobase pairs. Adenine (A) always pairs with thymine (T) and guanine (G) always pairs with cytosine (C). The "rails" are composed of alternating phosphates (P) and deoxyribose sugars (D). Although some people doubt whether these chemicals could have formed in a primitive earth atmosphere, nucleobases have been discovered in carbon-rich meteorites that reached the earth.

 The Structure & Function of DNA 
PCR: Polymerase Chain Reaction

According to Dr. Cora S. Thiel and her associates at the University of Zurich, plastid DNA can survive a flight through space and re-entry into the earth's atmosphere and still pass on genetic information. A team of scientists from UZH obtained these astonishing results during an experiment on the TEXUS-49 research rocket mission. Their research was published in PLoS ONE. November 26, 2014. DOI: 10.1371/journal.pone.0112979. Various scientists believe that DNA could certainly reach us from outer space as Earth is not insulated. Around 100 tons of extraterrestrial material made of dust and meteorites hit our planet every day.