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Research

During more than 40 years of research I have tackled many problems; some of the most interesting are described here.

Stable isotope mass spectrometers

My research career began when, as a Ph.D student, I encountered mass spectrometers. These instruments were able to analyse samples to measure their composition in terms of every element known, and moreover the abundance of their isotopes (variants of the element with the same chemical, but different physical, properties). The experience of Apollo taught me there was a need for more sensitive methods to investigate the isotopes of the elements carbon, nitrogen etc. which make up all living things. At the University of Cambridge, I pioneered methods that allowed measurements to be made on a thousand times smaller samples than anyone else.

A diamond is forever

When my group was working on building instruments to analyse tiny samples we were asked many times what geological problems these would be needed for on Earth. After all, we were told, you can obtain buckets of sample. One kind of material where this is not true is diamond. Using our new sensitive techniques we were able to show that not all diamonds are the same; they can have different isotopic compositions and different amount of nitrogen which can also be variable isotopically.

Interstellar grains

It is generally agreed that our solar system formed 4.55 billion years ago. For many years it was believed that it was produced from a cloud of gas that was so well mixed that there could be no memory of what happened at previous stages in the history of the Universe. Techniques I developed helped to recognise that interstellar grains have survived in meteorites. They are made of very resistant materials, such as diamond and silicon carbide. These minerals were created in supernovae and red giants: stars that lived and died before our sun and produced the elements that make up everything in our world, including the bodies of all living things.

Meteorite collecting programmes

For 200 years, scientists studying meteorites relied purely on luck to get the material for their research. Then in 1969 a group of Japanese glaciologists discovered that meteorites could be found in abundance on Antarctica because there is a mechanism to concentrate thousands of years of meteorites in fall. During the 1980s and early 1990s, I led a European initiative (EUROMET) to collect new meteorite specimens from both cold and hot deserts.

Death of the dinosaurs

Only about eight meteorites are seen to fall each year; as far as we know a person has never been directly hit. However in the geological past large asteroids or cometary fragments have caused major catastrophes on Earth leading for example the extinction of the dinosaurs. The evidence of such events can be found by analysing deposits left in the geologic record. Amongst the things that can be found are tiny diamonds produced in the impact explosion. It is possible that an asteroid may strike Earth at any time and wipe out civilisation. A small fragment of a comet hit the atmosphere over Siberia in 1908 to give a prediction of what might happen in the future.

Martian meteorites

When I heard, in the early 1980s, a suggestion that we had meteorites from Mars, my immediate thought was "crazy" but proving martian meteorites exist on Earth is one of the greatest scientific detective stories ever. One of the pieces of evidence being considered was that those samples contained trapped noble gases with the same relative abundance as measured in the martian atmosphere by the Viking lander. I suddenly realised that if this was true, the major constituent of the martian atmosphere (96% carbon dioxide) should be there too, and, lo and behold, it was. Since then we have found martian carbonates (minerals deposited in an aqueous environment) co-existing with organic matter that could be the remnants of a biological life that lived in the water.

From Beagle 2 to TB

One of the justifications for space exploration is that the technology developed has spin-off that affects our everyday lives. Mass spectrometers, such as those built for Beagle 2 and the Rosetta missions, which are light weight yet can survive the rigours of a rocket launch, and then operate semi autonomously consuming minimal power, could have an enormous number of applications on Earth where a portable devices are required. The skills of the team that built the Beagle 2 mass spectrometer are currently being utilised in a pilot project to decide whether gas analysis is capable of a real time detection of TB sufferers. At present in Africa, where TB is epidemic, it takes 6-8 weeks to confirm a diagnosis and there is a 50% probability the patient has died before treatment has commenced. There are many other applications for small portable mass spectrometers.

The search for HMS Beagle

When the name Beagle 2 was chosen for the UK's Mars lander to honour the ship, HMS Beagle, that Robert Fitzroy sailed around the world allowing Charles Darwin to collect evidence about the evolution of life on Earth, I began to wonder what happened to this iconic vessel. It transpired that it had been sold to act as a customs watch vessel in the Essex marshes. Marine archaeologist, Robert Prescott and I now believe we have located the final resting place and are hoping to recover some remains.