Christian Doppler

The man behind the effect

“The most rewarding research projects are those that delight the thinker and are of benefit to humankind."” This was Christian Doppler’s motto. And one could say he lived by it completely.

His discovery of the Doppler effect revolutionised applications in medicine, astronomy, aviation and numerous other technical fields.

Christian Doppler was born in Salzburg in 1803 and studied mathematics and physics at the Polytechnic Institute in Vienna and philosophy in Salzburg. After an assisting post in Vienna he took a professorship in Prague in 1835, before returning to Vienna, where he became the first Director of the new Physics Institute and, at the same time, the first Professor of Experimental Physics.

He had already published his main work – “On the coloured light of binary stars” – in Prague in 1842. In it he prophecised the Doppler effect. If the emitter of a wave is moving towards or away from the receiver the frequency is changed, increasing with movement towards and decreasing with movement away.

You are sure to have witnessed this effect, in traffic for example. When an emergency vehicle approaches, the siren seems markedly lower after it passes you.

Speed radars, ultrasound in medicine, air traffic control and measuring the distance of celestial bodies and whole galaxies are all based on Doppler’s discovery. Particularly modern astronomy would be hard to imagine without Doppler’s findings.