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Mars Exploration Rovers

Collage showingNASA Mars Exploration Rover Opportunity on the surface of Mars

Image: Courtesy NASA/JPL-Caltech

Once upon a time there was water on Mars! NASA discovered the evidence in minerals on the planet’s surface – using a method developed by a PhD student of theTechnical University of Munich half a century before. Aged just 32 at the time, Rudolf Mössbauer was awarded the Nobel Prize for this achievement.

The Mössbauer effect and water on Mars

In 2004, NASA space probes Spirit and Opportunity landed on Mars in search of clues to the history of our neighboring planet. As part of this venture, they collected rocks, analyzed them and sent the results back to Earth. During their many miles of exploration, they came across minerals that only form in the presence of water – thus proving that there must have been water on Mars at some point in time.

An essential instrument in identifying these traces was the Mössbauer Spectrometer, named after Munich physicist Rudolf Mössbauer. While working on his doctoral thesis at what was later to become the Technical University of Munich, in 1958 he discovered “recoilless nuclear resonance absorption of gamma radiation” – which he rapidly went on to demonstrate in practice.

Unknown rocks and materials – whether on Mars or Earth – can be chemically analyzed using this “Mössbauer effect”. Here, the spectrometer measures the characteristic gamma radiation scattered back by the atomic nuclei of certain elements when they are excited by a radioactive substance. In this way, the chemical compounds in the rocks can be clearly identified. In 1961, Rudolf Mössbauer – aged only 32 – was awarded the Nobel Prize for this discovery.

“Mössbauer’s discovery has been received with enormous interest. In many places, research into the Mössbauer effect is already under way. His discovery has made it possible to demonstrate the fundamental consequences of Einstein’s theory of relativity in the laboratory.”


Ivar Waller, 1961, Nobel Committee for Physics of the Royal Swedish Academy of Sciences, from the award ceremony speech for Rudolf Mössbauer

Bild: © ®The Nobel Foundation: Photo: Lovis Engblom

Radio interview with Rudolf Mössbauer (in German – Deutsche Welle 1968, 14’44 Min.)

In 1968, the Deutsche Welle interviewed the young Nobel Prize winner Rufolf Mössbauer, who had just returned to work in Germany – as professor at his Alma Mater, today’s TUM. In this interview, he does not only talk about how he managed to make his decisive discovery – but also compares the research conditions of the US and Germany at the time, and calls for stronger international exchange in sience. (Source: Deutsche Welle)

Curious? More discoveries and inventions spanning 150 years of TUM

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