In 2013, a small asteroid entered Earth’s atmosphere above the city of Chelyabinsk in Russia. Its shock wave broke windows and knocked down parts of buildings in six Russian cities and caused some 1,500 people to seek medical attention for injuries, mostly from flying glass. Can a Chelyabinsk-type event occur again? Definitely.
Late last week (March 29, 2019), astronomers at Mt. Lemmon, Arizona, discovered a fast-moving space rock. After calculations of its orbit, it was realized that the asteroid had made its closest approach to Earth one day earlier, on March 28. The asteroid has been designated as 2019 FC1. According to The Watchers website, this is the 14th known asteroid to fly past Earth within one lunar distance since the start of 2019. It is the sixth this month. With an estimated size of around 98 feet (30 meters) in diameter, it’s the largest asteroid to pass closer to us than the moon since 2019 began.
It passed closer to us than the moon, at around 26.8 percent of the Earth-moon distance, or 64,102 miles (103,162 km) from our planet. According to NASA, closest approach occurred on March 28, 2019, at around 05:46 UTC (1:46 a.m. ET); translate UTC to your time.
The asteroid that buzzed Earth on March 28 was travelling really fast. Its speed has been estimated at 57,973 miles per hour (93,298 km/h), or 25.9 km per second, relative to Earth.
Although most of the mass of an asteroid of its size would disintegrate during the passage through Earth’s protective atmosphere, it’s worth noting that this space rock was almost twice as wide as the asteroid that penetrated the atmosphere over the skies above Chelyabinsk, Russia, on February 15, 2013. For comparison, the Chelyabinsk asteroid was estimated to be 55 feet (17 meters) in diameter, before entering our atmosphere.
The Apollo-type asteroid has an orbit that brings it close to Earth’s orbit every 3.3 years, but, according to astronomers’ calculations, the 2019 approach was the closest for this particular asteroid for at least the next 89 years.
Bottom line: A small asteroid – now designated as 2019 FC1 – flew closer to us than the moon (64,102 miles or 103,162 km) on March 28, 2019. Astronomers detected it one day later and calculated its orbit backwards. With an estimated size of around 98 feet (30 meters) in diameter, it’s the largest of 14 asteroids to pass closer to us than the moon since 2019 began.
Eddie Irizarry of the Sociedad de Astronomía del Caribe (Astronomical Society of the Caribbean) has been a NASA Solar System Ambassador since 2004. He loves public outreach and has published multiple astronomy articles for EarthSky, as well as for newspapers in Puerto Rico. He has also offered dozens of conferences related to asteroids and comets at the Arecibo Observatory.