Bennu Asteroid Photo: NASA
Bennu was identified in 1999, and has a diameter of almost 500 metres, making it big enough to cause a global catastrophe if it ever hits the earth. NASA has been keeping a close eye on it, because it crosses our orbit ever 6 years, and in 2135 it will pass extremely close to earth, coming between earth and the moon. The concern is that earth's gravitation pull could put it on a collision course with earth later that century.
Astronomer Ian Griffin, who is the head of the Otago Museum, has previously worked at NASA and has discovered many asteroids himself.
