A car-size asteroid was discovered by the astronomers hours before it slammed into earth. Meteorologists noticed an unusually bright flash signature over the Caribbean waters 170 miles south of Puerto Rico. It was about 13 to 16 feet in diameter or the size of car. “Scientists in Hawaii initially spotted the asteroid, named 2019 MO, on Saturday (June 22). Soon after, the heavenly traveller broke apart in large fireball as it hit the atmosphere about 240 miles (380 kilometres) south of San Juan, Puerto Rico,” according to the University of Hawaii.
“This is only the fourth time in history that scientists have spotted an asteroid so close to impact. The other three detections all occurred within the past 11 years, including 2008 TC3, 2014 AA and 2018 LA, which landed as a meteorite in southern Africa just 7 hours after it was noticed by scientists,” Live Science reported.
The asteroid's explosion produced a dramatic infrasound signal in the form of an "airwave" that rippled out around it. According to waver vapor imagery shared by SpaceWeather.com, the asteroid split into at least three pieces. The explosion itself released an energy equivalent to more than 6,000 tons of TNT, the fireball itself weighing 200 tons.
“For the first time, astronomers at the University of Hawaii have demonstrated that their ATLAS and Pan-STARRS survey telescopes can provide sufficient warning to move people away from the impact site of an incoming asteroid,” the institute wrote.
Now that ATLAS is up and running (it began operating in 2015), it will detect all kinds of asteroids, big and small. The system's two telescopes, situated 100 miles (160 km) apart, scan the night sky for asteroids every two nights. Since then, they have discovered about 100 asteroids larger than about 100 feet (30 m) in diameter every year.