“One astronomical unit is close to the mean distance between the Sun and Earth approximately 150 million kilometres – about 93 million miles.”
Asteroid BM123 is flying towards our planet at speeds of about 8.14km per second or 18,208mph (29,304kmh).
At this rate, the space rock will appear closest to Earth around 12.45pm GMT (7.45am EST) tomorrow.
Based on NASA’s observations, the rock measures somewhere between 157ft and 360.8ft (48m and 110m) in diameter.
At the upper end of the estimate, the asteroid is taller than Big Ben’s clocktower in Westminster, London.