Seeing Earth's origin through beer-goggles
Despite all the chatter about how important oxygen is (and it is), every day we breathe in far more nitrogen. Earth's atmosphere is composed of 78% of the stuff compared to 21% oxygen. We know that the first photosynthesizing bacteria and...
Despite all the chatter about how important oxygen is (and it is), every day we breathe in far more nitrogen. Earth's atmosphere is composed of 78% of the stuff compared to 21% oxygen. We know that the first photosynthesizing bacteria and later, plants, bulked up the air with O 2, but where did all that N come from? Beer of course!
Bear with me.
Earth's nitrogen, like all the goodies that make our planet a rich and fascinating world, traces its origin back 4.56 billion years to the protoplanetary disk.
Within this enormous flattened disk of dust and gas, the planets, comets and asteroids formed through gravitational attraction, collision and re-assembly of ice-coated dust particles contributed by previous generations of stars, much of it from supernovae.
In a recent article in New Scientist Dennis Harries of the Friedrich-Schiller University in Jena, Germany describes rummaging through meteorites collected in Antarctica in the 1970s. Meteorites, particularly the stony variety called chondrites, contain minerals and gases from the original nebula that have been little altered since their origin.
In their study, Harries and colleagues turned up a brand new crystalline mineral composed of a rare combination of nitrogen and chromium which they named "carlsbergite" for the Carlsberg Foundation, an offshoot of the Danish brewery, which funded previous work on it. See, I told you this was about beer.
Next, Harries measured the amount of different isotopes or varieties of nitrogen were present in the meteorites. Isotopes are two or more forms of the same element that have the same number of protons in their atomic nuclei but a different number of neutrons. Nitrogen-14, the most common form that makes up over 99% of known nitrogen, has 7 protons and seven neutrons. Other varieties exist like nitrogen-13 (with just 6 neutrons) and nitrogen-15 (8 neutrons).
The group discovered that mix of nitrogen isotopes was nearly identical to that found on Earth which suggests a common origin in the protoplanetary disk. Nitrogen's pretty boring though. In its pure form it doesn't react with anything, but when hooked up to three hydrogen atoms it makes quite a stink. We call it ammonia - chemical formula NH 3.
Harries believes that dust grains afloat in the dusty disk may have been covered by thin shells of ice containing ammonia and other compounds. A large body, such as a newly-forming proto-planet, moving through the icy gas could have created a shock wave which heated the gas and evaporated the ice.
Now in vapor form, the chemicals could react together to form new materials including carlsbergite and possibly amino acids, where nitrogen is a key component. Somehow, somewhere the very first living things assembled amino acids into proteins. You gotta start somewhere.
Which brings me to a wish. Should the Coors Brewing Company decide one day to fund an investigation into meteorites and scientists uncover yet another new mineral, "coorslite" naturally comes to mind.