Asteroid Florence measures about 4.4 kilometres wide.
Large asteroid to pass close to Earth
One of the largest asteroids recorded in Earth's vicinity is to pass close to us on Friday.
Asteroid Florence will maintain a distance of about seven million kilometres, or about 18 Earth-Moon distances.
Florence is among the largest near-Earth asteroids that are several miles in size.
Measurements from NASA indicate it is about 4.4 kilometres wide in size.
NASA says this "relatively" close encounter provides an opportunity for scientists to study Florence up close.
It says radar images will show the real size of Florence, and could also reveal small surface details.
Asteroid Florence was discovered by Schelte "Bobby" Bus in Australia back in March 1981.
It is named after Florence Nightingale, the founder of modern nursing.
Friday's encounter is the closest by this asteroid since 1890 and the closest it will ever be until after 2500.
Paul Chodas is manager of NASA's Centre for Near-Earth Object Studies (CNEOS).
"While many known asteroids have passed by closer to Earth than Florence will on September 1st, all of those were estimated to be smaller.
"Florence is the largest asteroid to pass by our planet this close since the NASA program to detect and track near-Earth asteroids began."
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