A SCIENTIST YOU SHOULD KNOW Dr. Clair Patterson isn’t necessarily one of the best known scient

A SCIENTIST YOU SHOULD KNOWDr. Clair Patterson isn’t necessarily one of the best known scientific names of the 20th century, but he’s a name you ought to know. His work not only changed our understanding of the Earth, but also has had a profound impact on the life of everyone reading this post.Dr. Patterson’s career started during the 2nd world war, where he worked at Oak Ridge laboratory, amongst other places, dealing with uranium, an element that would be key to his scientific contributions.After the war and completion of his Ph.D., Dr. Patterson began developing the Uranium-Lead age dating system. Uranium has 2 naturally occurring isotopes, with masses of 235 and 238. Both isotopes are radioactive, and over a period of millions of years, decay to form lead. The rate at which radioactive decay happens is constant for each isotope and can be measured. By the 1950’s, for Uranium, these decay rates were well known, in no small part because of their usefulness in nuclear weapons.Dr. Patterson surmised that since he had the decay rates, he could measure the age a rock by measuring the amount of uranium and lead in the rock. After testing showed promise, he tried an interesting sample; the Canyon Diablo meteorite (pictured). This rock is an iron meteorite, and there is a lot of it; its impact formed Meteor Crater in Arizona. Dr. Patterson and colleagues realized that dating a meteorite using this technique could date the formation of the solar system, as the elements would have been trapped in the rock since it first formed.He measured abundances of uranium and lead isotopes in the rock, applied the decay constants, and found that the age of the rock was 4.55 billion years. This age has been replicated many times in many samples, but this measurement was the first time humans measured the age of the Earth.Dr. Patterson then turned his attention to another problem. To make this measurement, he had to establish a clean lab, free of lead contamination. Turns out, one of the major contaminants he had to deal with was that people would enter the lab. Dr. Patterson’s measurements established that because of the presence of lead in gasoline (and other places), people were being exposed to amounts of environmental lead that verged on lead poisoning. His work helped establish that lead pollution was now everywhere; for example, the amounts of lead entering the ocean had multiplied by a factor of 10. He spent years dealing with politicians and eventually became a leader in convincing governments to phase out leaded gasoline. Ever since, lead contents in people’s bodies have been declining, with a host of potential health and societal benefits.Every time you fill up your gas tank with unleaded gasoline, take a moment and think of Clair Patterson, and how he not only dated the Earth, he helped save you from lead poisoning. I think it’s a fair tribute.-JBBDr. Patterson’s Memoir and image:http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/patterson-clair-c.pdfImage from Dave Pape, shared for noncommercial use under creative commons license: http://www.flickr.com/photos/64279203@N00/4440188873Patterson, 1956: “Age of meteorites and the Earth”http://www.sciencedirect.com/science/article/pii/0016703756900369 -- source link

More pics about