Last night a 900 foot wide asteroid made the latest in a series of close approaches towards Earth.
There is a chance it could collide with the Earth in 2036, the biggest threat would be if it fell on land mass.
Speaking to ITV Daybreak, Dr Maggie Aderin-Pocock said if it hits a city it would cause devastation.
More top news
An internet troll who told a Jewish Labour MP she would "get it like Jo Cox" is facing jail for a second time.
Detectives investigating the attempted abduction of an RAF serviceman at Marham have released e-fit images of the suspects.
The National Trust has published a list of 50 things for children to do before they turn 11 and three-quarters, such as climbing a tree.