Today you are talking to us about works of art
Yes, because next Wednesday, March 8, there will be at Lilliad Learning Center Innovation, on the scientific city in Villeneuve d’Ascq, a conference open to all and free of journalist and columnist Loïc Mangin, who will reveal some scientific secrets works of art.
And you are going to reveal some of these secrets to us before the time!
Of course ! There is for example the one concerning the Christ on the cross by Salvador Dali entitled Corpus Hypercubus. Well this painting is a real window on the 4th dimension! Dali represented the cross there as a 4-dimensional hypercube seen from our three-dimensional space. Yes, Dali had some good notions of mathematics! Another example concerns the altarpiece of the mystical lamb by the Van Eyck brothers, which can be admired in the cathedral of Ghent. The secret concerns the fruit that Eve holds in her hand.
It’s not an apple?
No. And in fact, it is not written anywhere in the bible that the forbidden fruit was an apple. Lucas Cranach depicts an apple in his Adam and Eve, but Michelangelo depicts a fig in the Sistine Chapel. In the Van Eyck brothers’ altarpiece, it is clearly not an apple, the skin resembles that of a citrus fruit, and it took a real investigation to finally identify… an Adam’s apple. This is the name of a variety of lemon that Jan Van Eyck probably discovered during one of his trips to Spain.
Eve biting into an Adam’s apple! Awesome !
Science also makes it possible to date works of art very precisely. It is this time astronomy and geography that we will seek. The position of the moon in the painting Lever de lune – Haystacks by Vincent van Gogh indicates that it was painted on July 13, 1889 at 9:08 p.m. The level of the tide and the position of the sun in the painting Impression soleil levant by Monnet allows us to date it to Wednesday November 13, 1872, at 7:35 a.m. a unique character. It is, for example, physics that makes it possible to understand the little miracle of the colors of the cup of Lycurgus.
The cup of Lycurgus?
It is a Roman glass cup from the 4th century, which is currently in the British Museum. When you light the cup normally, it is green. If you put the light source inside the cup, it is red.
Does it change color depending on the position of the lighting?
Exactly ! And that’s because it is made of a glass, the golden ruby, which contains gold flakes. They are nanoscale flakes, therefore invisible to the naked eye, and what is extraordinary is that they are not dyes or pigments, which usually give objects their color.
But where do the colors come from?
These are called structural colors, because they come from the interaction of light with the structure of the material itself. There are also structural colors with the butterfly wings, notably the morpho, a very metallic blue when viewed by reflection, while the wings are transparent if the light source is behind the butterfly. To find out more, I encourage you to come and listen to Loïc Mangin next Wednesday. And if you have time, come a little early and visit the exhibition on the precious plaques of Auguste Ponsot, in the building just opposite. You will see structural color photographs precisely. They are centenarians, and since there are no pigments, they have not taken a wrinkle, and their colors are much more vibrant than the usual photos. I put you as always all the information on the site ramenetascience.fr.