Up to a million asteroids could be on course for the Earth over the next century, according to a new study by Chinese astronomers. As SCMP reports, while the risk of collision is low and most of the asteroids are less than 100 metres (328 feet) across - small compared with the one that wiped out the dinosaurs - each one has more kinetic energy than an atomic bomb, and we know little about them.
The small size and large number made these short-term hazardous asteroids (SHA) extremely difficult to track, said Professor Gan Qingbo and colleagues at the Space Debris Observation and Data Application Centre at the China National Space Administration.
"The accurate identification of impact threat targets and early warning capabilities requires more precise algorithms for orbit determination and impact risk assessment," they said in a paper published in domestic peer-reviewed journal Acta Astronomica Sinica on Thursday.
Astronomers have focused on bigger asteroids with the potential to hit the Earth.
Asteroids with a diameter in tens of metres have not been regarded as a serious threat, with little interest in how many SHAs were out there, or when they would come.
