ASTEROIDS: HOW LIKELY IS IT THAT WE'LL BE STRUCK BY ONE?

It’s happened before, so what are the chances of another catastrophic collision with a space rock?

- JAMES LLOYD

If you believe some recent headlines, an asteroid is threatening to derail democracy by blasting into Earth on 2 November – the day before the US elections. In reality, the space rock, called 2018 VP1, has only a 0.41 per cent (1 in 240) chance of hitting us. And even if it does, it’s only around two metres in diameter, so it’ll disintegrate in the atmosphere long before it’s had chance to ruffle any presidential hairdos.

CLOSE ENCOUNTERS

As its name suggests, 2018 VP1 was discovered in 2018, and it’s just one of around 23,500 ‘near-Earth objects’ (NEOs) being tracked by NASA’s Center for NEO Studies (CNEOS).

NEOs are Solar System bodies which have orbits that bring them in close proximity to us (defined as coming within around 200 million kilometres of the Sun). A small number of NEOs are comets, but over 99 per cent are asteroids – rocky objects that are the leftover building blocks from the formation of the Solar System.

To work out the possibility of a NEO hitting Earth, CNEOS calculates the object’s orbit around the Sun using data provided by observatories around the world. The more observations CNEOS has of a NEO, the better it can pin down the object’s future trajectory.