Asteroid dangerously close to hitting Earth

AN ASTEROID will pass within a ‘ hair’s breadth’ of Earth in 120 years, astronomers warn.

Nasa is launching a probe to collect a sample from the huge rock, named Bennu, to trace its orbit. Scientists fear it is getting nearer and in 2135 will pass dangerously close, between the Moon and Earth.

Bennu was discovered in 1999 and has been monitored by experts who fear it could collide with our planet.

Dante Lauretta, Nasa’s lead investigator in the probe mission, said it could cause ‘immense suffering and death’, adding: ‘That 2135 fly-by is going to tweak Bennu’s orbit, potentially putting it on course for the Earth later that century.’

The professor of planetary science at Arizona University said: ‘We need to know everything about Bennu – its size, mass and composition. This could be vital data for future generations.’

Professor Lauretta said the probe, Osiris-Rex, will first aim to map every detail of the asteroid. It will then descend and hover above its surface to pick up some rubble.

The probe will spend a year surveying the asteroid’s geology, and looking for sites where the rock is loose enough to retrieve a sizeable sample. It will be launched in September and is expected to return in 2018.

Nasa hopes the probe will investigate a force that can send asteroids on a new path.

Professor Lauretta said: ‘The Yarkovsky effect is the force that acts on an asteroid when it absorbs sunlight and then radiates it back into space as heat.

‘It acts like a small thruster, constantly changing its course.’

The asteroid is expected to pass the Earth at a distance of 180,000 miles – well inside the Moon’s orbit and close enough to alter the asteroid’s path.

Professor Lauretta added: ‘We estimate the chance of impact at about one in 2,700 between 2175 and 2196.’ His team also predicts that an impact of that size would be equivalent to triggering three billion tons of high explosive.

Professor Mark Bailey, of the Armagh Observatory in Northern Ireland, said that while the risk from Bennu was relatively small, it ‘falls on the boundary, in terms of size, for an object capable of causing a global catastrophe’ if it hits Earth.