Astronomers have discovered a new hanger-on competing with the moon for Earth's attention.

At less than 100 metres (300ft) across, the 'mini moon' – called 2016 HO3 – isn't actually orbiting Earth but is taking a path around the sun which overlaps with our own.

Scientists say that because its solar orbit is relatively stable, the little asteroid is likely to stick with us for centuries to come.

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Astronomers have discovered a quasi-satellite following Earth through space. The cosmic hanger-on, called 2016 HO3 isn't actually orbiting Earth but is taking a path around the sun which overlaps with our own

COSMIC TINY DANCER 2016 HO3 isn't actually orbiting Earth but is taking a path around the sun which overlaps with our own. It was first spotted on 27 April, 2016 and astronomers estimate it to be between 40 to 100 metres (120 to 300 ft). Scientists believe it has likely been with us for decades, going unnoticed as its path is benign. And as its solar orbit is relatively stable, the little asteroid is likely to stick with us for centuries to come. Advertisement

Nasa scientists have called the rocky object a 'quasi-satellite', revealing how it spends half of the year in front of us and the other half trailing behind.

'Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the sun, we refer to it as a quasi-satellite of Earth,' said Paul Chodas, manager of Nasa's Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California.

It was first spotted by on 27 April this year by astronomers at the Pan-STARRS 1 asteroid survey telescope in Hawaii.

But scientists believe it has likely been with us for decades, going unnoticed as its path is benign.

However, the little rock is not the first space rock to get a little clingy, with rocks coming in a change of cosmic dance partners.

Chodas added: 'One other asteroid, 2003 YN107, followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us.

'Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth's companion for centuries to come.'

Nasa scientists have called the rocky object a 'quasi-satellite', revealing how it spends half of the year in front of us and the other half trailing behind

Astronomers say that it wobbles slightly, drifting up and down in Earth's orbital plane, and that Earth's pull makes the orbit contort over the decades, stopping it from drifting too near or too far.

NEAR EARTH ASTEROIDS NEOs are comets and asteroids that have been nudged by the gravitational pull of the giant planets in our solar system into orbits that allow them to enter Earth's neighbourhood. Eight of the objects discovered in the past year have been classified as potentially hazardous asteroids (PHAs), based on their size and how closely their orbits approach Earth. Advertisement

'The asteroid's loops around Earth drift a little ahead or behind from year to year, but when they drift too far forward or backward, Earth's gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the moon,' added Chodas.

'The same effect also prevents the asteroid from approaching much closer than about 38 times the distance of the moon. In effect, this small asteroid is caught in a little dance with Earth.'

As of April this year, scientists were aware of hundreds of near Earth objects (NEOs) - comets and asteroids that have been nudged by the gravitational pull of the giant planets in our solar system into orbits that allow them to enter Earth's neighbourhood.