Florence will pass Earth at a safe distance of 4.4 million miles (7 million kilometers). That is about 18 times the average distance from Earth to the moon, or 18 X 238,857 miles. Watch the video simulation of the track of this asteroid here.
Many asteroids have a moon and even satellites. The dog-bone shaped asteroid Kleopatra has two moons. These moons were named Alexhelios and Cleoselene in 2011. this year.
Related reading: The 7 Strangest Asteroids in the Universe