Image: Oliver Denker/Shutterstock
Both the US and Russia have shared details, separately, of their plans to stop an extinction-sized asteroid from colliding with the Earth.
As we now know, our planet is incredibly vulnerable to asteroids both big and small that enter a collision course with Earth.
If one just a few kilometres wide hits our planet, our species could be wiped out in a matter of years, if not moments.
The question is, what can we do to stop it?
Coincidentally, both NASA and a group of Russian researchers have separately come up with their own solutions that – perhaps unsurprisingly – suggest the use of powerful and deadly nuclear weapons.
NASA’s idea is something called the Hyper-velocity Asteroid Mitigation Mission for Emergency Response, or HAMMER for short.
While still just on the drawing board, the idea would be to equip a spacecraft with either a nuclear weapon at its tip, or an 8.8 tonne kinetic impactor.
This gives NASA and astrophysicists on Earth the flexibility of deciding whether it is small enough to go the safer route with a smaller impactor, or go with the nuclear option (literally) and blow up the larger or more unpredictable asteroid before it reaches our planet.
One asteroid the space agency has been eyeing for some time is Bennu, an object more than 1,000ft wide in a close orbit of Earth that would prove devastating if it were to hit our planet.
While blowing Bennu up sounds pretty simple, the reality is much more complicated. The closer an asteroid is to Earth after going undetected, the more problems the nuclear option would cause. It is possible that a relatively close asteroid could fracture into smaller – but still dangerous – pieces that would cause immense damage to Earth.
An amazingly simplistic image of what the Russian proposal would do to an asteroid. Image: Elena Khavina/MIPT Press Office
The Russian option
However, Russian scientists are a little more optimistic about the nuclear option having run extensive tests in the lab by replicating the destruction of an asteroid, but on a much, much smaller scale.
In a paper published to the Journal of Experimental and Theoretical Physics, the team detailed how they fired a laser beam at a model asteroid measuring just 4mm long, requiring 200 joules of energy to destroy it.
The team – which comprises researchers from the Moscow Institute of Physics and Technology, Russian Federal Nuclear Centre and the nuclear energy company Rosatom – estimated that, on this basis, it would take a 3 megaton nuclear weapon to destroy an asteroid measuring 200m across.
While by no means a perfect study, Karen Daniels of Carolina State University said the findings were still useful.
“This one study goes a long way towards specifying the circumstances under which deploying a nuclear charge at the surface of an asteroid might be sufficient to address crises, as well as pitfalls that would cause it to fail,” she said to Gizmodo.
