An asteroid on a collision course with Earth has burned up in the evening sky over southern Africa eight hours after first being noticed.
The asteroid, dubbed 2018 LA, was discovered out near the Moon’s orbit early on Saturday morning.
Asteroid trackers at NASA and elsewhere determined the rock to be about 2 metres wide.
Automated alerts were sent out to the community of asteroid observers to obtain further observations, and to the Planetary Defence Coordination Office at NASA headquarters in Washington.
However, since the asteroid was determined to be so small, no further impact alerts were issued by NASA.
Video posted on YouTube, from a farm just across the border in South Africa, showed a fireball swiftly descending and getting bigger, and then a blinding flash in the sky.
Asteroid 2018 LA seen from a farm between Ottosdal and Hartebeesfontein, north-west South Africa.
It burst apart several kilometres up, according to NASA.
Initial estimates had the impact zone stretching from southern Africa across the Indian Ocean into New Guinea, with tracking systems then narrowing it down to southern Africa.
NASA officials said the scramble among scientists and observers of the small asteroid was merely a good training exercise.
“This was a much smaller object than we are tasked to detect and warn about,” NASA’s planetary defence officer Lindley Johnson said in a statement.
“However, this real-world event allows us to exercise our capabilities and gives some confidence our impact-prediction models are adequate to respond to the potential impact of a larger object.”
It is the third-time scientists have spotted an incoming asteroid on a direct collision course with Earth.
In 2008, an asteroid measuring 4 metres was spotted 19 hours in advance. It came apart above Sudan, as predicted.
A 2014 asteroid was discovered just a few hours before entering over the Atlantic, with little time for tracking.
All three asteroids were discovered through the Catalina Sky Survey near Tucson, Arizona, which is run by the University of Arizona and funded by NASA.
The same asteroid hunter, Richard Kowalski, made all three discoveries.
“We search the night sky methodically nearly each clear night,” he said.
“While it is good fortune that I happened on this object, it is what our program is designed to do.”
Objects this small, “are quite faint and hard to detect until they are very close, which is why we did not see it sooner”, he said.