Asteroid clarity

By Keith Budge, Headmaster, Bedales Schools

A precious thing about being a member of the Bedales community is that you can find yourself sitting in a lecture theatre on a Tuesday evening, hearing about an entirely fascinating subject from a world expert in his field.  How many of my school or university contemporaries were doing that on a rainy Tuesday night?

The occasion is the inaugural Kadian Harding Lecture, a series set up in memory of Kadian, a young student with a fascination with astronomy, who died tragically in July 2012.

The lecturer is Professor Gareth Wynn-Williams, Emeritus Professor of Astronomy at the University of Hawaii.  The talk proves to be not only a masterclass in the history of asteroids, but a fine example of excellent communication, both to specialists and non-specialists.

Especially in retrospect, given the events unfolding in the American elections during the lecture, I know that we were all wondering, “Is my knowledge of all these asteroids whizzing around going to make me think that the world is an even more dangerous place?”  Well, here is some much needed good news: people like Gareth have been making very good progress, especially over the past twenty years or so.  In 1800, say, they didn’t know much about asteroids; indeed interest lay mainly in the Earth, Sun and a mere six planets.  Now – scary fact – we know there are at least 700,000 asteroids; however, comfortingly, cunning ways of tracking the biggest ones and those which are showing any signs that they might collide with Earth over the new few (million) years are in operaton.  Yes, we know who you are and, in the improbable event of you heading, say for Petersfield, we would need to make haste to leave and ensure we didn’t stand near glass windows if the asteroid explodes high up in the sky.  Titchy asteroids can still be troublesome and cause a nasty dent in your car, but the bigger the asteroid, the more warning you get and so you can (in an orderly fashion) scarper.

There are some cracking facts and wonderful analogies that anchor it all in the enthralled minds of people like me. To think that the Earth is moving at about 20 times the speed of a bullet or that the Helyabinsk asteroid that exploded in Russia in 2013 had the force of 600,000 tons of TNT or the power of 40 x the Hiroshima bomb.  The shots taken of this bring it all home – people standing by windows which shatter as they are looking out.

As for those poor dinosaurs, they died out, we think, as a result of the asteroid that hit Chicxulub in the Yucatan Peninsula, Mexico, 65 million years ago, causing the mother of all craters and making the Earth’s atmosphere opaque for years.  The crater is 180 km wide and the asteroid was, we think a stonker at 10 km in diameter.  The evidence is all there in the layer of iridium at the K-T boundary in many 65 million year old rocks.

Thanks to the advance of science, we are all a little less likely to go the way of the dinosaurs – at least as a result of being smitten by an asteroid.