Scientists have moved closer to being able to stop a
huge asteroid colliding with the Earth and potentially wiping out human life.
Researchers at the University of Tennessee have
discovered that blowing the space rock up could make the collision worse by
causing several devastating impacts.
Instead, small changes could be made to its surface
to disrupt the forces keeping it together and cause it to break up in outer
space.
They were studying asteroid 1950 DA, which first
became infamous in 2002 when astronomers estimated it had a one in 300 chance
of hitting the planet on 16 March, 2880.
However, the odds of a collision were
later revised to a more reassuring one in 4,000.
The asteroid has a diameter of one kilometre and is
travelling at nine miles a second relative to the Earth, which it would hit at
38,000 miles per hour.
The impact would have a force of around 44,800
megatonnes of TNT and cause a huge explosion, tsunamis and change the climate
of the globe, devastating human life.
But with 35 generations to go until its possible
arrival, scientists are confident that the disaster can be averted.
The findings, published in the science journal
Nature, could prompt a change in tactics defending our planet.
Previous research has shown that asteroids are loose
piles of rubble held together by gravity and friction but by calculating 1950
DA’s thermal inertia and bulk density, the team detected the action of cohesive
forces that stop it breaking up.
Ben Rozitis, a postdoctoral researcher, said if only
gravity were holding it together, the spinning would cause it to fly apart.
The rotation is so fast that at its equator, 1950 DA
effectively experiences negative gravity and if an astronaut were to attempt to
stand on the surface, he or she would be thrown off into space.
The presence of cohesive forces has been predicted
in small asteroids but definitive evidence has never been seen before.
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