Could A Cosmic Lasso Divert Extinction-Level Asteroids?

IN 2013, A METEOR EXPLODED 22.5 KM (14 MILES) above Chelyabinsk, Russia, knocking out windows across 500 km2 and injuring more than 1 600 people. It was a wake-up call for astronomers to help defend Earth from more potentially hazardous asteroids.

- Jennifer Leman

Of the almost one million known comets and asteroids in our solar system, more than 2 000 have the potential to be hazardous to Earth. These asteroids are typically 140 m wide or larger, on an orbit that swings them within 22.5 million km of Earth’s orbit. ‘Although asteroid deflection might sound like science fiction, it is a serious topic,’ says Flaviane Venditti, PhD, an observatory scientist at the Arecibo Observatory in Puerto Rico. ‘Out of all natural disasters, an asteroid impact is the only one we have the power to avoid.’

Proposed defensive measures against oncoming asteroids look blunt so far. Later this year, NASA will attempt its Double Asteroid Redirection Test (DART). This mission will involve slamming an ovensized spacecraft into an asteroid called Dimorphos – scheduled to make a close (but safe) approach to Earth in 2022 – as scientists measure how the impact changes Dimorphos’s trajectory. It’s risky to Hulksmash an Earth-bound, extinction-level asteroid, though. ‘In general, when we move an asteroid, we want to keep it in one piece,’ says planetary astronomer and DART co-lead Andrew Rivkin, PhD, of Johns Hopkins Applied Physics Laboratory. The rock could break apart and create a wave of several smaller ‘citykilling’ asteroids instead. (This risk also applies to an Armageddon-style nuclear solution, we’re told – there are no plans to test a space nuke at this time.)