A 6-foot (2 m) wide asteroid called 2018 LA disintegrated harmlessly over Botswana, Africa, just hours after its discovery on Saturday morning (June 2, 2018).
2018 LA was first discovered by the NASA-funded Catalina Sky Survey, located near Tucson and operated by the University of Arizona.
Although there was not enough tracking data to make precise predictions ahead of time, a swath of possible locations was calculated stretching from Southern Africa, across the Indian Ocean, and onto New Guinea.
Reports of a bright fireball above Botswana early Saturday evening match up with the predicted trajectory for the object.
2018 LA entered Earth’s atmosphere at the high speed of 38,000 mph (17 km per second) at about 16:44 UTC (9:44 a.m. PDT, 12:44 p.m. EDT, 6:44 p.m. local Botswana time) and disintegrated several miles above the surface, creating a bright fireball that lit up the evening sky.
When it was first detected, the asteroid was nearly as far away as the Moon’s orbit, although that was not initially known.
It appeared as a streak in the series of time-exposure images taken by the Catalina telescope.
As is the case for all asteroid-hunting projects, the data were quickly sent to the Minor Planet Center, which calculated a preliminary trajectory indicating the possibility of an Earth impact.
The data were in turn sent to the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory, where the automated Scout system also found a high probability that the asteroid was on an impact trajectory.
Automated alerts were sent out to the community of asteroid observers to obtain further observations, and to the Planetary Defense Coordination Office at NASA Headquarters in Washington.
However, since the asteroid was determined to be so small and therefore harmless, no further impact alerts were issued by NASA.
“This was a much smaller object than we are tasked to detect and warn about,” said Dr. Lindley Johnson, Planetary Defense Officer at NASA Headquarters.
“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.”
“The discovery of asteroid 2018 LA is only the third time that an asteroid has been discovered to be on an impact trajectory,” said Dr. Paul Chodas, manager of the CNEOS.
“It is also only the second time that the high probability of an impact was predicted well ahead of the event itself.”