Cosmos: The Clean Room

While previous episodes of Cosmos have hung their central narratives around a single historical individual's story, The Clean Room has the strongest such line yet, being really about the life and work of Clair Patterson, a man who made not one but two significant scientific contributions in his lifetime.

Cosmos, while standing head and shoulders above the average science documentary we see on US or UK TV channels these days, cannot escape their trappings entirely. This is never more clear than in this programme's pre-advert break animated sequences showing Patterson being horrified by germ-like apparitions that cover every surface and which only he can see. These scenes are overly dramatised and blatantly exist to create a fake sense of suspense - stay tuned to this channel until after the break to find out what's going on, viewers!

Patterson's first breakthrough concerned the scientific question of how old the planet Earth actually is. Tyson illustrates the difficulty with a visually impressive scene where he lifts the geological layers of the Grand Canyon (beat that Brian Cox!) but they don't hold the answer because the layers are laid down at different rates.

The idea was that meteoric rocks formed at the same time as the Earth, and their age could be measured by the constancy of radioactive decay - to find out when the matter in the solar system (and hence the Earth) was formed, measure the amount of uranium that has decayed into lead in meteorites.

Patterson set to the task but could not get consistent readings on how much lead there was because of the sheer amount of environmental contamination from lead that was not in the sample he was trying to study. It required extreme measures to clean the lab of lead - it took Patterson 6 years and required him to create the world's first ultra-clean room - but this led to success, and the discovery that the world was four-and-a-half billion years old.

So that was Patterson's first major scientific achievement. The second was linked to it, following on from his work on lead, and so Tyson just carries on the story.

Lead poisoning was known about by the Romans, but it was still used as a material by them and right up to the early 20th century, when leaded petrol caused workers exposed to it in quantity to go mad and die. Robert Kehoe - villain of the piece - was the scientist hired by General Motors to say that lead posed no danger to the public and that the amount of lead in the environment was natural and absolutely not the fault of his corporate sponsors. Whew, public relations disaster averted!

Our hero Patterson began to investigate the lead in the atmosphere by looking at the contamination of the world's oceans. When he published his findings in the "Nature" journal, it took just 3 days for the petroleum and chemical industry to withdraw his funding and try to get him fired. Why, it was almost as if they had something to hide!

The government backed Patterson and he supported his findings from the deep oceans by investigating Antarctic ice. For those who were being kept in suspense by the pre-advert teaser scenes, the 'germs' are revealed to be lead, present in everyday scenes at artificially high levels as a man-made byproduct of (leaded) petrol being emitted by cars all over the world.

Senator Muskie held hearings in the US, at which Kehoe (boo!) and Patterson (hooray!) gave evidence contradicting each other. And after 20 years the US government banned lead in petrol.

It may have taken a while, but this was a victory for science over corporate self-interest. Tyson concludes the episode by taking these events as a template for how important the independence and objectivity of science needs to be.

While I have heard of and, in some cases, know the stories of many of the scientists featured in Cosmos, I had never heard of Clair Patterson before seeing this fascinating programme, and never would have imagined that the age of the Earth and the dangers of lead in petrol were discovered by the same man.