Excuse me, this is amazing.
There are a billion theories and mysteries surrounding the Mona Lisa (ie: our favourite; that it was actually Da Vinci's self-portrait, in drag) and they have baffled us humans since it was painted in the 16th century. Beginning the famous painting in 1509, Da Vinci apparently "lingered" over it before its completion in 1519. All this lingering apparently added up to Da Vinci's technique being impossible to understand.
Recently scientists (Philippe Walter and his team at the Laboratoire du Centre de Recherche et de Restauration des Musees de France) thought they had busted the code, Dan Brown style; using a turbo-fancy x-ray machine, said scientists believed they could uncover the ways that Da Vinci created the seemingly impossible shadows and light to create her flawless skin-tone on the painting.
What they found out is that the painting has 30 layers of paint on it. Big deal? Those 30 layers of paint add up to 40 micromemtres of paint. According to Gizmodo that's about the same as the width of half
a human hair.
Walter says that it is still impossible – even with this high-tech super-future x-ray machine – to find any brushstrokes on the Mona Lisa
. More at cnn.com