Ellen Phiddian
Cosmos science journalist
Powerful X-rays could be a viable way to divert asteroids on collision courses for Earth, according to a new study.
The study, published in Nature Physics, uses lab-based experiments to suggest that X-rays might be useful for deflecting asteroids up to 4km in diameter.
The chances of a large asteroid hitting the Earth are very low, but they have the potential to cause mass extinctions, and colossal damage to the Earth’s environment.
Two years ago, NASA’s DART mission proved it was possible to redirect an asteroid with a spacecraft.
But this method is expensive and requires enough warning time to send a craft into space, which may not always be possible.
A faster, but riskier, way to deflect asteroids would be to use X-ray pulses generated by nuclear explosions.
These pulses would heat the surface of an asteroid and cause some of its material to vaporise.
The expanding gas made of vaporised rock would deflect the asteroid’s movement, robbing it of momentum.
Since there aren’t many asteroids close to the Earth, it’s difficult to test this method.
This team of researchers, who are from Sandia National Laboratories in the USA, simulated asteroid redirection tests in the lab by firing X-rays at 12mm-length rocks.
One of these “mock” asteroids was made of quartz, while the other was made of fused silica, which has been observed in a lot of real meteorites.
The team placed each rock in a vacuum chamber, suspended by very thin metal wires.
They then fired X-ray “scissors” at the rocks, vaporising the wires and some of the rock simultaneously, to see how it moved.
They found that both rocks were deflected at speeds of roughly 70 metres per second.
The researchers extrapolate this to suggest that the X-ray method could work for asteroids as big as 4km in diameter.
“We demonstrate that scaled asteroid deflection experiments can be accurately performed and without space flight,” write the researchers in their paper.
