Simon Stephen’s famous fall experience was repeated five centuries later, with a cosmic development

Stephen conducted the experiment in 1584 using two lead balls of different masses: one ten times heavier than the other. The question he wanted to answer: Do you hear a beep or two when you land?

It was believed that the balls fall at the same time, so the speed of the fall does not depend on the mass of the ball. This won’t work with two hits. Then Stephen and an observer on Earth heard a single snap, and they laid an experimental basis for the subsequent gravitational research of physicists such as Isaac Newton and Albert Einstein.

Theory of relativity

The physics behind this synchronous perturbation is now known in physics as the “weak equivalence principle” and is intertwined with Einstein’s general theory of relativity. However, physicists still re-examine it to look for gaps in the current physical understanding of reality.

This time, the researchers did not drop balls from a higher tower, but rather used a satellite that placed it in Earth orbit. Inside were two objects: one of titanium alloy and the other of platinum alloy, differing only in mass.

Since objects in orbit are constantly falling around the Earth, the two alloys in the satellite are also falling. The researchers then measured whether one might fall a little faster than the other, so they could determine – just like Stephen several centuries ago – whether it really does depend on mass. The so-called microscope experiment actually ended in 2018, but it took so far to complete the entire analysis.

more accurate

In publications in trade journals, among others physical review Letters Researchers wrote on Wednesday that the potential fall deflection between objects cannot be greater than one quadrillion (1,000,000,000,000,000,000). This makes it the most accurate definition of the weak equivalence principle ever.

Astronomer Vincent Ike (Leiden University) is pleased that the new result once again draws attention to the long history of this experiment. ‘Especially because it was not Galileo Galilei who performed this from the Tower of Pisa, as many believe – a whole monkey story! – but Simon Stephen of Delft. What he accomplished at that time was amazingly clever.’

According to Icke, the “too smart” result again does not solve a convincing physics problem, he asserts. “It’s especially good to know.”