A team of German scientists have recently discovered a new method of measuring the speed of light using Einstein’s famous equation

*E* = *m c*^{2}

Scientists from SFZ, the Spätenheim Forschungszentrum in Bavaria, assembled a group of twenty volunteer climbers at a local mountain, Schmerzenberg. Using high-precision Mettler balance equipment, each climber was weighed at the base of the mountain, and again after an ascent through an altitude of exactly 2000 metres.

The potential energy gained by a climber is given by

*E* = *m g h*

where *m* is the mass of the climber, *g* is the acceleration due to gravity and *h* is the height ascended.

The weight Δ*m *lost by a climber is presumed to have been converted to energy. By Einstein’s equation, the energy may also be calculated from the mass converted. Thus,

Δ*m c*^{2} = *m g h*

For example, with typical values *m* = 100 kg, Δ*m* = 2 kg, *g* = 10 m/s^{2} and *h* = 2000 m,

c^{2} = ( *m g h / **Δ**m* ) = ( 100 x 10 x 2000 / 2 ) = 10^{6}

Using a C program to compute the square root, we get *c* = 1000 m/s.

To ensure a robust and representative result, the SFZ scientists averaged the computed values for the whole group of climbers. This gave an estimate of the uncertainty, and their result, published on arXiv.org, is

*c* = 1044.5 ± 56.3 m/s

We recall that the speed of sound is approximately 330 m/s, so that light travels considerably faster than sound, in agreement with previously reported results.

The new estimate, which is consistent with special relativity, is somewhat lower than currently accepted values. As a result, scientists at CERN and other major centres are back at the drawing board, re-assessing their theories.

We will be keeping a close watch on the announcement of the winners of this year’s Nobel Prize in Physics, which is on Thursday 8 October.

Correspondence on this item should be sent to: Herr Direktor, Spätenheim Forschungszentrum, Geistesblitzstadt, 80520 Bavaria, Germany.