Researchers from the University of California, Irvine have built a three-dimensional model of the Salvator Mundi  painting of Leonardo da Vinci and unraveled the secret of the most expensive work of art in history, MIT Technology Review reported.

Scientists focused on the transparent ball, which Jesus Christ holds in his hand. The ball, which symbolizes the universe, practically does not distort the space behind itself - for a long time this phenomenon has caused numerous questions among researchers of da Vinci's work.

The analysis to which American scientists subjected the 3D model of the painting showed thata a hollow sphere is in Christ's hand. The thickness of the glass of which the sphere is made is more than 1.3 mm. The ball is twenty five centimeters distant from the body of Christ. In order to correctly calculate the parameters of the distortion created by the ball, Leonardo da Vinci had to have rather deep knowledge of optics.

The painting was considered lost for a long time. In 2017, it was sold at Christie's auction for $ 450 million - the work of da Vinci, thus, became the most expensive piece of art in history.