Asteroid Florence has passed unusually close to our planet, offering a rare treat for both professional and hobby astronomers. Scientists said there was no danger that the large object would hit Earth.
The asteroid flew by at the distance of 7 million kilometers (4.4 million miles) from our planet on Friday, which 18 times further than the distance between the Earth and the Moon. Scientists estimated that Florence was around 4.4 kilometers in diameter.
"While many known asteroids have passed by closer to Earth than Florence will on September 1, all of those were estimated to be smaller," said Paul Chodas, manager of NASA's Center for Near-Earth Object Studies (CNEOS).
"Florence is the largest asteroid to pass by our planet this close since the NASA program to detect and track near-Earth asteroids began."
Researchers tracked the event using ground-based radars in California and Puerto Rico. The large object is also visible for hobby astronomers in the first nights of September.
Florence's size projected to downtown Berlin
"The resulting radar images will show the real size of Florence and also could reveal surface details as small as about 30 feet (10 meters)," NASA said.
'Once every few million years …'
Florence orbits the sun every 859 days in an elliptical path, making encounters like the one on Friday rare. According to NASA's calculations, the Friday pass is Florence's closest since 1890. It will take almost 500 years before it once again comes this close to Earth.
It was first detected in 1981 and named after the nursing pioneer Florence Nightingale.
Florence is one of thousands of the so-called near-Earth asteroids, which make up a relatively small segment of celestial bodies compared to the millions of asteroids gathered in the asteroid belt of our solar system.
Approximately once a year, a car-sized asteroid hits the Earth atmosphere and burns up before reaching the ground.
"About every 2,000 years or so, a meteoroid the size of a football field hits Earth and causes significant damage to the area," said NASA.
"Finally, only once every few million years, an object large enough to threaten Earth's civilization comes along."
Both the American and the European space agencies are looking for ways to secure humanity against any large asteroid threat.
dj/tj (AFP, dpa)