An important discovery has been made concerning the possible inventory¹ of molecules² available to the early Earth. Scientists led by Sandra Pizzarello, a research professor in ASU's Department of Chemistry and Biochemistry, found that the Sutter's Mill meteorite³（陨星）, which exploded in a blazing fireball over California last year, contains organic molecules not previously⁴ found in any meteorites⁵. These findings suggest a far greater availability of extraterrestrial organic molecules than previously thought possible, an inventory that could indeed have been important in molecular⁶ evolution and life itself. The work is being published in this week's Proceedings⁷ of the National Academy of Sciences. The paper is titled "Processing of meteoritic⁸ organic materials as a possible analog⁹ of early molecular evolution in planetary environments," and is co-authored by Pizzarello, geologist¹⁰ Lynda Williams, NMR specialist Gregory Holland and graduate student Stephen Davidowski, all from ASU.

 

Coincidentally, Sutter's Mill is also the gold discovery site that led to the 1849 California Gold Rush. Detection of the falling meteor by Doppler weather radar¹¹ allowed for rapid recovery so that scientists could study for the first time a primitive¹² meteorite with little exposure to the elements, providing the most pristine¹³（原始的） look yet at the surface of primitive asteroids¹⁴.

 

"The analyses of meteorites never cease to surprise you ... and make you wonder," explains Pizzarello. "This is a meteorite whose organics had been found altered by heat and of little appeal for bio- or prebiotic chemistry, yet the very Solar System processes that lead to its alteration¹⁵ seem also to have brought about novel and complex molecules of definite prebiotic（生命起源以前的） interest such as polyethers."

 

Pizzarello and her team hydrothermally treated fragments of the meteorite and then detected the compounds released by gas chromatography-mass spectrometry. The hydrothermal conditions of the experiments, which also mimic¹⁶ early Earth settings (a proximity¹⁷ to volcanic¹⁸ activity and impact craters), released a complex mixture of oxygen-rich compounds, the probable result of oxidative processes that occurred in the parent body. They include a variety of long chain linear and branched polyethers, whose number is quite bewildering（使人困惑的）.

 

This addition to the inventory of organic compounds produced in extraterrestrial environments furthers the discourse¹⁹ of whether their delivery to the early Earth by comets and meteorites might have aided the molecular evolution that preceded the origins of life.

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