Asteroids 'causing nuclear-scale explosions above Earth'

Powerful asteroids hitting the Earth's atmosphere caused 26 nuclear-scale explosions between 2000 and 2013, including one that was much stronger than the atom bomb that destroyed Hiroshima, a report has found.

The findings came from the Nuclear Test Ban Treaty Organisation, a global infrasound network that detects nuclear weapon detonations and recorded the impacts over 13 years.

Most explosions occurred too high in the atmosphere to cause any serious damage on Earth but "the only thing preventing a catastrophe from a ‘city-killer’-sized asteroid has been blind luck," said former astronaut Ed Lu as he revealed the data at the Museum of Flight in Seattle today, NBC reported.

Mr Lu added that while large asteroids have been detected, "less than 10,000 of the more than a million dangerous asteroids with the potential to destroy an entire major metropolitan area have been found."