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
Arkansas has become the first US state in 17 years to carry out back-to-back executions after putting two inmates to death.
Up to three million children risk going hungry over the school holidays, with increasing numbers of families relying on food banks, MPs say.
Tuesday will be a cold and windy day across the British Isles with a mix of sunshine and showers.