Monica Grady: When Space Comes Down to Earth
Thursday, 25 February 2016
Bolton School Girls’ Division pupils studying maths and the sciences were delighted to meet Monica Grady, Professor of Planetary and Space Science in the Faculty of Science at the Open University. Professor Grady is one of the UK’s leading space scientists and primarily focuses her work on meteorites. She has also worked on the European Space Agency’s Rosetta mission: this launched a spacecraft to orbit a comet in 2004, with the craft finally reaching the comet a decade later. A video of Professor Grady’s enthusiastic reaction to Rosetta’s robot probe Philae landing on the comet went viral in November 2014.
She came into School to talk about meteorites, or “when space comes down to Earth.”
She opened her talk with video of a meteorite which fell over the Russian town of Chelyabinsk in 2013 and was well-documented thanks to the many dashboard cameras in use at the time. Professor Grady emphasised that this was a particularly large meteorite, but even so it had not been predicted. It came out of nowhere, and caused most of the windows in the town to shatter. She said, “This is just to give you some idea of just how destructive these things can be that come from space.”
Professor Grady then went on to talk about meteorites more generally: where they come from, how they are classified, and why it’s interesting and important to study them.
She explained that most meteorites originally come from asteroids, which were formed along with the rest of the solar system. Meteorites therefore allow scientists to look back at what conditions were like in the solar nebula 4,567 million years ago.
However, in order to study meteorites, scientists have to find them. Professor Grady talked about some of the amazing places she has visited while meteorite hunting, including the Nullarbor Plain in Australia and the blue ice desert of Antarctica. She talked about her amazing experiences in both these remote locations, including the fun she had while there and the realities of fieldwork in difficult conditions.
As well discussing meteorites large enough to be collected, Professor Grady explained that most of the extra-terrestrial material that falls on the Earth each year is dust. Pupils were amazed to discover that a tiny piece of dust that was less than 50 microns in length created a 3 centimetre hole in the insulation blanket of a satellite because it was travelling so fast. This really put into perspective the potential damage that even small particles can do, particularly to satellites or to the International Space Station.
Finally, Professor Grady talked about some historical meteorite impacts and near-misses, including the last few impacts in the UK and the Tunguska event in Siberia, and finally discussed the probability of a large impact on Earth. She closed her talk by reiterating the fact that scientists cannot predict when and where meteorites will fall.
“I just want you to be aware that things from space can come down at any time, and they’re really, really, really exciting and interesting to study. Really, really important,” she said to end her lecture. “What we do need are more people to study space and study engineering, technology, maths, and physics, because they’re the subject areas that take you to really, really exciting places. I studied maths, physics and chemistry for my A Levels, and I reckon if you study maths, physics and chemistry, that will take you anywhere. It’s taken me to Antarctica. It’s taken me to the Arctic Circle. It’s taken me to the middle of Russia, to Japan, to Hawaii – it’s taken me all over the world, and it’s a great subject area to be in, so all I can do is say: do maths, physics and chemistry, and the world will be yours.”
She then opened the floor to questions. One of the girls asked how she felt when she realised that the Philae lander was going to ‘die’, which allowed Professor Grady to talk more about the Rosetta mission and specifically the feat of landing a robot probe on a comet, which had never been done before.
She talked about her initial delighted reaction to the landing, and the fact that no one realised at that time Philae had bounced. However, the lander did eventually come back down onto the surface of the comet, though not in the intended location or the right way up. She said, “We knew we were going to get seventy hours of science out of it, which we did. We got 80% of the science. Then it was, ‘When the comet gets closer to the sun, will the solar batteries charge up, and will Philae wake up?’ Philae did wake up in June and it was really exciting again, but unfortunately the antenna had been knocked off and so it couldn’t communicate properly with Rosetta. The comet’s gone around the sun, it’s come away, and it’s now too dark where the comet is for the sun to be heating up Philae’s batteries. So they reckon Philae has gone into eternal hibernation, which sounds very, very sad. So, I was sad, but Philae did its work properly.”
The whole of Year 11, Sixth Form pupils studying mathematics and the sciences, and some Year 9 pupils were able to attend this fascinating talk. A number of girls approached Professor Grady at the end to ask questions as well, which she was delighted to answer.