In a neat bit of fast-paced detective work, NASA has backtracked from an image of a meteor that exploded over the Caribbean Sea to confirm it marked the demise of an asteroid detected just 12 hours earlier. Estimated to be only 16 ft (5 m) in size, the space rock was too small to pose any danger, but it did demonstrate the space agency's growing ability to monitor potentially hazardous asteroids.

The incident began at 5:45 am EDT on June 22, when the asteroid, now designated 2019 MO was detected by the University of Hawaii's ATLAS survey telescope on Mauna Loa in Hawaii. At that time, the asteroid was 310,000 miles (500,000 km) from the Earth, which NASA says makes it as hard to detect as a gnat more than 300 miles away.

What happened next was essentially automatic. ATLAS data from four observations was sent to the NASA-funded Minor Planet Center at the Smithsonian Astrophysical Observatory, which is tasked with tracking asteroids and especially ones likely to impact the Earth. It then went to the Jet Propulsion Laboratory in Pasadena, California, where it was automatically processed by the Scout automated impact-analysis software.

The software determined that the asteroid had a high probability of impacting the Earth, but was determined to be so small as to most likely burn up in the upper atmosphere. The whole matter would have ended there, except that on the evening of June 22, the NOAA-NASA weather satellite GOES-16 caught a flash over the Caribbean on its Geostationary Lightning Mapper, which matched the profile of a bolide – that is, a meteor that explodes when it enters the atmosphere.

This caught the attention of Davide Farnocchia, a scientist at the Center for Near Earth Object Studies, which operates Scout. He suspected that the flash could have been caused by the just discovered 2019 MO and tried to calculate its possible trajectory between where it was observed and where it might have exploded.

Unfortunately, the four ATLAS observations weren't precise enough for that, but the Pan-STARRS 2 survey telescope on Maui had been photographing the same region of the sky at the same time. Using this data, Pan-STARRS scientists Robert Weryk and Mark Huber from the University of Hawaii Institute for Astronomy and Marco Micheli at the European Space Agency were able to refine the trajectory calculations and confirm that the flash was caused by 2019 MO.

Only 12 hours had passed since the sighting. The impact was later confirmed by international infrasound observations and other sensors operated by the United States.

"Asteroids this size are far smaller than what we're tasked to track," says Farnocchia. "They're so small, they would not survive passing through our atmosphere to cause damage to Earth's surface. But this event shows how capable our search programs are, even for objects of such small sizes."

Source: NASA