Marie Curie’s Notebooks Someday Will Not Be Radioactive
We will only have to wait a little more than 11,000 years
86 years have passed since two times Nobel Prize winner Marie Skłodowska Curie left us. This July 4th, we are reminded of her everlasting legacy to science and to the world.
To science, she left many contributions to radioactivity and the discovery of radium (Ra) and polonium (Po). To the world, she left the recordings of her scientific endeavour, her laboratory notebooks.
Currently, Curie’s lab notebooks are carefully stored in lead-lined boxes at France’s Bibliotheque National. Visitors can only take a look after signing a liability waiver and wearing a special suit to protect them against radiation. While reasons why Curie’s belongings are still radioactive have been explained before, some details have been left out.
Curie’s notebooks contain radium (Ra-226) which has a half-life of approximately 1,577 years. This means that 50 percent of the amount of this element breaks down (decays) in approximately 1,600 years. But after this time, still, 50 percent of radium will exist. Doing some calculations, it can be estimated that 90 percent of radium content would break down in roughly 5,000 years. Now, will the notebooks be any safer then? That is not known.
As radium decays, other radioactive elements form as well as alpha, beta, and gamma rays. Beta and gamma rays can travel through our skin and bodies, respectively, and can harm us. While a thin layer of glass or metal is enough to protect ourselves against beta rays, gamma rays need at least a shield of 1.3 feet of lead. For this reason, we need special protection even if we only wanted to take peek at Curie’s notebooks.
But, will radiation ever stop? The answer is yes. Radiation will stop when radium decomposition pathway reaches the formation of the stable and nonradioactive element lead (Pb-206). Now, for this to happen more than 99 percent of radium should have broken down. And guess what, that would take about 11,200 years.
One thing I know, Marie Curie’s lab notebooks will keep reminding us of her science for many more years. And even when radiation is all gone, her handwriting will still be there. Only then, we won’t require to protect ourselves to see it on display.
