Murchison meteorite – an early glimpse inside a comet

WARWICK HOLMES

We had a tantalising glimpse of what a comet was like when this meteorite came and hit Australia, called the Murchison meteorite, and inside this meteorite, they realised that there was something very strange, because when it hit this town of Murchison – which is in Victoria in Australia – the residents of the town saw it come in, there was this enormous bang as it went at sonic speed through the atmosphere. But there was a smell that was left behind – a smell of bitumen and wet hay was the best way that they could describe it. They thought, well that’s very strange. What on earth is that?

They analysed the chemistry of this rock and found more than 100 amino acids in this rock from the outer extent of our Solar System, because they realised that this was, in fact, an evaporated core of a comet. There are only 20 amino acids on Planet Earth and in all of our bodies. So there’s an extra 80 amino acids in this rock from space, which we’ve never seen before. We know what the chemistry of them looks like, we can make them in a lab, but they do not occur naturally on Earth.

This was very exotic chemistry that we found just on what we thought was an inert rock from deep space. It’s anything but. It brought with it the fundamental chemistry that helped kick start life. So we realised immediately something very, very strange was going on with comets, and we wanted to go out there and find out what it was.

The Science Learning Hub would like to acknowledge the following for their contribution to this resource:
Warwick Holmes
Lecture video footage courtesy of the University of Waikato
Image of Murchison meteorite courtesy of Basilicofresco and licensed under Creative Commons Licence 3.0