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this is grace and today i'm going to

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tell you a romantic story about making

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prebiotic organics from helium crust via

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hypervelocity impacts this research is

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funded by nasa fundamental laboratory

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so do you know that in the first few

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hundred million years after earth's

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birth from 4.1 to 3.8 billion years ago

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meteors comets and asteroids of

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different sizes heavily bombarded on

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earth's surface a period of time

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commonly referred as punitive late heavy

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bombardment

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these impact events are often considered

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being destructive to life

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at least we think

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dinosaurs are killed by impactors

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however re-examination of heavy

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bombardments yield different

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perspectives

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exogenous impactors may not only have

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seeded sterile earth with water and

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essential organics that originated in

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the outer space

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but also have enabled synthesis of new

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organic materials as they penetrate

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through the primitive atmosphere slammed

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into the ocean layer and collide with

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the crust

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imagine a juvenile earth without any

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organic materials carbon and nitrogen

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would have stayed as inorganic compounds

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and gotten recycled between atmosphere

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ocean crust and mantle

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though the specific mechanism remain

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controversial majority of the carbon and

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nitrogen in the mantle could have

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outgassed as carbon dioxide and nitrogen

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gas due to an early oxidation of the

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mantle and therefore creating a carbon

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dioxide and nitrogen dominated neutral

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atmosphere

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the composition of the primitive crust

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is likely ultramafic as suggested by

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remnants of comedians that formed

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billion years ago

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interaction of co2 with calcium and

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magnesium ions that dissolve from the

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ultramafic minerals can soon form

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secondary carbonates

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in the pore space and fracture zones as

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suggested by the laboratory experiments

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and also the video showing you here

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extensive synthetization can introduce

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nitrogen in the form of ammonia ions to

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substitute potassium in the clay

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minerals that present in the hydrous

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ultramafic rocks

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this process could have been extremely

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efficient on early earth considering

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elevated

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volcanic outgassing rates and the more

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vigorous hydrothermal circulation driven

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by a higher surface heat flow

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consequently a considerable amount of

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carbon and nitrogen could have been

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accumulated in the early earth's crust a

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hidden reservoir that have never been

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considered as a significant source of

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carbon and nitrogen to form prebiotic

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organics

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in this study we really want to know if

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we could synthesize prebiotic organics

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using inorganic carbon and nitrogen in

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the crust via hypervelocity impact if we

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to answer these questions we simulate

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hypervelocity impact plasma environment

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using high power post laser ablation

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we use q-switch laser at 1064 nanometer

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under a minimum laser energy 70

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millijoule and a pulse width of 9

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nanoseconds

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this laser enabled irradiance greater

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than gigawatts per centimeter square

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sufficient to generate the thermodynamic

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plasma state of silica vapor generated

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by collision of two prosodic bodies

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the laser system was steered and

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irradiated on the sample pallet

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we performed all experiments at 10 to

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the -5 pascal of the chamber pressure in

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order to mitigate the interference from

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ambient carbon dioxide and nitrogen gas

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ions form in the plasma but then

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extracted and accommodated by ion optics

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and sent to quadruple mass spectrometer

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each of our sample pallets contain a

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source of carbon which is carbonate here

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and a source of nitrogen from

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nitrogenous salt they can either be

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sodium nitrate or ammonium chloride

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heavy labeled materials are also used

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a quadruple mass spectrometer measures

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the nominal mass of the ions and their

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intensity

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recombination of carbon and nitrogen

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that released from the both reactants

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allowed the formation of cyanide ions cn

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when the ablation target was prepared

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using a single isotopic labeled material

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the mass of recombination ions will

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shift from 26 to 27.

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when both of the reactants are labeled

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the mass station will shift to 28.

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this migration of the peaks as a

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function of the input materials

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reinforce that carbon and nitrogen atoms

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stand from the solid starting material

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in the plasma plume to form new species

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here are four mass spectrum observed

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from the simulation experiments using

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calcium carbonate and ammonium chlorides

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as starting materials

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each spectrum is a summation of 20 skins

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and the y-axis is normalized to the

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total number of

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ions detected in each spectrum

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the background of each spectrum has been

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identified using stepwise baseline

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regression and subtracted from the raw

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spectrum

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in the label 3 experiment we observe the

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recombination of cn and cno at mass 26

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and 42 respectively

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as we start to label a single reactant

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we start to observe the peak shifted to

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mass 27 and 43

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when both of the reactants were heavy

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labeled we detect peaks at mass 28 and

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44.

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we repeat similar experiments using

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calcium carbonate and sodium nitrate and

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observe comparable mass peaks at mass 26

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and 42.

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the peak shifted with the application of

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isotopic doped reactants

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we also observe an o2 as the

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decomposition product from nitrate salts

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in the meantime we realize accumulation

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of ions in the chamber that has been

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detected in the mass spectrum such as

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chlorine in the nitrate experiment

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despite multiple sources of signals both

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ammonium chloride and sodium nitrate

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experiments distinguish cn and cno from

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other potential isobaric interfaces

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providing confidence that the source of

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carbon and nitrogen are derived from the

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to provide complementary insights into

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the chemical and physical process

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associated with bombardments that may

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affect organic synthesis we explored a

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second method to simulate hypervelocity

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impact environment

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we used physical bombardment of carbon

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60

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bucket balls on nitrogen-rich substrate

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having labeled carbon 13 bucket ball was

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ionized accelerated and bombarded on an

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ammonium nitrate substrate at velocity

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greater than 70 kilometer per second

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the ions generated were detected by a

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we observed isotopic labeled cn and cno

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peaks at mass 27 and 43 respectively

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when heavily labeled carbon 13

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60 bucket ball

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bombarded on ammonia nitrate target

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the isotopic labeled material are used

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then we observe migration of the peak to

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the significant peaks at the other mass

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station were observed during the

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experiment due to the presence of 20

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carbon 12 contamination sourced from the

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the cn and cmo yielded at mass station

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28 and 44 nonetheless represent

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recombination products from the labeled

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input material

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we compared and contrast the yield of cn

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and cno between reduced nitrogen in

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ammonia and oxidized nitrogen in the

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nitrate form

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the arrow bar represents two standard

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deviation of the eos from four

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experiments

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the observation suggests that cyanide

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ions can be produced via hypervelocity

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impacts at a similar rate irrespective

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of the redux states of the substrate

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the two-fold difference in yields of cmo

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suggests that reduced nitrogen in

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ammonium form is more efficient at

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with the both experiments we have

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demonstrated the capability of

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synthesizing prebiotic organics via

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hypervelocity impacts using source of

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carbon and nitrogen from the crust

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the next question is how much prebiotic

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organics could we have synthesized

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to address these questions let's

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estimate the total reservoir size i mean

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the crustal residual size of carbon and

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nitrogen available for the organic

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spontaneous sequestration of carbon

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dioxide into the ultramafic oceanic

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crust and ejecta could have stored a

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significant amount of carbonate on the

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surface

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the crust alone could have trapped 3

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times 10 to the 21st moles of carbon

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dioxide based on the box model of global

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carbon dioxide cycling through

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abiotic fixation of nitrogen gas to

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nitrogenous salts is the rate limiting

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steps and has to rely on energetic

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process such as lightening in atmosphere

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or chemical reducing agents near

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hydrothermal vents

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assume an average 5 times 10 to the 10

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moles nitrogen gas is converted into

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nitrogenous salts per year the crustal

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budget of nitrogen is estimated to be 10

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assume all materials are distributed

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evenly on the earth's surface we could

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have a surface concentration of carbon

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and nitrogen as 10 to the 13 or 10 to

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the 10 moles per cubic kilometers

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respectively the mass of the ejecta that

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shocked to vaporize is under orders of

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six times the mass of the incoming

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impactors that traveled at 20 kilometer

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per second

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given the projected mass frequency of

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impactors during the late heavy

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bombardment

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we calculate the mass of impactors that

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are above the threshold impactor size to

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penetrate an ocean layer and generate

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sufficient ejecta

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the estimated total

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of 3 times 10 to the 8 cubic kilometer

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of cluster material could have been

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vaporized from the crust

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if 0.1 mole percent of the vaporized

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carbon and the nitrogen recombined and

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condensed as organic the continent and

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oceanic crust could have generated a

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total of 10 to the 15 and 10 to the 18

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moles of organics during the 300 million

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years of heavy bombardment

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this is equivalent to an organic

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production rate 10 to the 7 to 10 to the

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10 moles per year at least four orders

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magnitude higher than the previous

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estimate of organic production rate via

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atmospheric shock in neutral condition

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the story does not end here after newly

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combined organics were rained down to

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the crater they could have reacted with

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water and catalytic

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substrates near the crater basin to form

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molecular building blocks such as amino

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acids nuclear bases

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clay minerals formed due to the

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post-impact synthetization plus red dry

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cycling could have promoted the

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absorption of a comprehensive

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panel of monomers and facilitate

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self-assembly of molecules

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interstitial pore space and fractures

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near the crater surface could have

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offered the optimal habitats to

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concentrate polymerized carbonic organic

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compounds

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and showing them from harmful uv

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radiation and successive impact events

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on the surface

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because of these reasons hypervelocity

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impacts could have been an invaluable

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mechanism to live its emergence on earth

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and this is great i hope you enjoy my