Queenie Hoi Shan Chan, Lecturer in Earth Sciences, Royal Holloway
Scientists have long known that certain ingredients are needed to support life, especially water and key organic chemicals like carbon. In recent years, both ingredients have been found on giant asteroids and other celestial bodies.
But, until now, no study had delivered conclusive evidence, based on extraterrestrial samples, to show how and when organic matter was made on the rocks that gravity flings around our solar system.
Alongside a group of international scientists, my team has been analysing some of the minuscule particles taken from one such rock: an asteroid called 25143 Itokawa. Our study found organic matter – the raw ingredients for life – had been produced on the surface of Itokawa, as well as being delivered there via meteorite and space dust impacts.
It is the first time a research team has shown that organics were created in situ on asteroids, and that this organic content may have evolved when other organic material hit the asteroid’s surface over time. With this knowledge, we can speculate about the evolution of Earth’s surface chemistry over the billions of years that preceded the first spark of life on our planet.
Each day, between 50 and 150 meteorites that weigh over 10 grams hit the Earth’s surface. These tiny rocks could bear chemical clues about our solar system, but as soon as they enter our atmosphere – and especially after they’ve struck Earth – they become contaminated, distorting and erasing the clues they arrived with.
That’s why space missions have set out to collect samples directly from asteroids as well as from a comet, the Moon and Mars: to inspect extraterrestrial particles that haven’t been sullied by terrestrial contaminants.
One such mission was launched by the Japan Aerospace Exploration Agency (JAXA) back in