Sunday, April 23, 2017

Abundance of elements on planet earth correlates with year of discovery

We hypothesized that chemical elements that are more abundant and easier to purify in elemental form would be discovered earlier. Obvious evidence for our hypothesis is that heavier elements such as Tennessine have been synthetically created and have been first described as late as the past decade. A better way to evaluate our hypothesis would be to look at all chemical elements discovered till now.

Using the timeline of chemical element discoveries from wikipedia and comparing to the abundance of these elements shows a significant negative correlation (r=-0.27; p-value: 0.0002421). Below figure show the golden age of discovery of chemical elements stretching from 1600 to 2000. Although many of the commonly used metals were well known to the "ancients", a large majority of the elements were discovered within the span of the last 400 years. The negative correlation suggests that less abundant materials were discovered later than the more abundant materials. Rapid discovery of chemical elements overlaps with the timing of the great divergence.

Chemical element abundance vs Year of discovery

Since the abundance of elements on earth is negatively correlated (r=-0.45; p-value: 8.336e-10) with the atomic numbers of the elements, we see a positive correlation (0.53; p-value < 2.2e-16) between the atomic number of elements and when they were discovered. Instead of just using the abundance of elements, a better measure would be the weight of both abundance and ease of extraction.

It would be interesting to see if such correlations would exist on other planets. Would the class of the planet determine the correlation?

The star trek Voyager episode "Emanations" set in the year 2371 (stardate 48623.5), says that 246 elements are known to federation science. This is almost double the number known now. This suggests another age of discovery in the near future. The BBC has an interesting article on what new wonders await us in the outer reaches of the periodic table. However, as yet it is not clear how far the extended periodic table can be extended synthetically and how many of these elements will be found naturally.