Cosmos: A Spacetime Odyssey Episode 7: “The Clean Room” — This week we learn how Clair Patterson’s quest to find out the age of the earth led (lead?) to one of the biggest health reforms of all time.
This week on Cosmos: A Spacetime Odyssey we learn the story of Clair Patterson, the scientist who was able to figure out the age of the earth, thanks to some zircon and a mass spectrometer. Following this discovery, his continued research led to discovering the health dangers of lead in consumer products. His advocacy may have been one of the biggest accomplishments in public health.
Here’s how the awesomeness played out on this week’s episode:
How many years are in a begat?
If you were wondering how the idea of the earth being only about 5,500 years old came about, it began with Archbishop James Ussher. In the 1650s, he developed a chronology based on a passage from the second book of Kings that referenced the death of Nebuchadnezzar. Based on some other historical events mentioned in the bible, and an approximation of lifespans (multiplied by the 130 or so “begats”), the Earth was supposedly created on Saturday, October 22, 4004 B.C. Neil deGrasse Tyson adds it was probably sometime around 6pm. SHADE.
A Birthday Gift from the Asteroid Belt
If you are looking to figure out the age of a celestial body, the most reliable method is to measure the amount of lead in an object. Celestial bodies are filled with radioactive particles which gradually become lead as they decay. The rate of decay is constant, so if you can determine the ratio of lead to uranium in a given object, you can determine how old that object is. For example, there’s a huge crater in Arizona that was created from a meteorite. The meteorite deflected off of an object in the astroid belt between Mars and Jupiter. Using the lead:uranium measurements in rocks at the impact site, scientists were able to determine that the impact occurred about 50,000 years ago.
This Zircon is Clean
This form of measurement was instrumental in determining the age of the earth. Clair Patterson was an average student who was a whiz with a mass spectrometer. After working on the Manhattan Project, he was tapped by Harrison Brown at the University of Chicago to test zircon particles to determine the age of the earth. If Patterson could measure the amount of lead in the zircon, he would have his answer. However, just tossing a sample into a mass spectrometer isn’t going to provide the answer. There is so much lead in the environment (we’re talking parts per million here) that an accurate reading is almost impossible to gauge. It wasn’t until Patterson was able to construct a clean lab at the California Institute of Technology that he was able to get his answer: 4.5 billion years old.
Lead-ers in PR
The thing about lead: it is beyond toxic. In the human body, lead is able to mimic other minerals that our bodies process, such as zinc. Lead also causes clogs in neural-transmitters, which is not a desirable outcome. Despite these horrible side effects, paint companies like Dutch Boy had a PR blitz in the early 1900s celebrating the awesomeness of lead paint and how safe it is. Kinda horrific.
Thanks Clair Patterson!
Patterson continued to do research in the oceans and the antarctic, but he noticed something curious. Lead content in water increased as you get closer to the surface. What could account for that increase? Perhaps the runoff from leaded gasoline? Patterson made his initial discovery while his research was funded by petroleum companies. When Patterson wouldn’t back down from his conclusion, his funding was cut. However, Patterson continued to pursue his research and testified in the senate. This led to lead reforms, eliminating lead-based paints and requiring unleaded gasoline. The positive impact of these reforms is one of the biggest accomplishments in public health, with symptoms caused by lead poisoning in sharp decline since the reforms took hold. Yay!