According to NASA, the largest asteroid named ‘Florence’ will pass by Earth on September 1, 2017. This is going to be a safe encounter between the space rock and Earth. The size of the asteroid is about 4.4 kilometres and it will seep past earth at a distance of 7.0 million kilometres (about 18 Earth-Moon distances). The space enthusiast can witness the asteroid with the help of small telescopes as it will visible for several nights between in the early September.