Monday, July 6, 1998 Published at 16:54 GMT 17:54 UK
Asteroid found inside Earth's orbit
Asteroid Ida, a similar shape but far larger than 1998 DK36
Astronomers have found, and then lost, a 40-metre asteroid that orbits between the Earth and the Sun. Our science editor David Whitehouse reports
Asteroids are chunks of rock that orbit the sun. They range in size from a few metres to hundreds of kiometres in size. More than 5,000 are known.
The mostly circle the Sun between the orbits of Mars and Jupiter but they can turn up almost anywhere in the solar system - even orbiting between the Sun and the Earth.
The significance of the discovery is not that the object is large, (it is only 40 metres in size) or that it poses a threat to the Earth. But scientists are worried that there maybe many more.
The new object has been designated 1998 DK36 and was seen in February - but was lost after a day. It is hoped that it can be found again later in the year.
Due to its orbit, if 1998 DK36 had been on collision course with the Earth we would never have seen it coming. This is because most survey's for Earth-threatening asteroids look outward and not inward.
If 1998 DK36 had struck the Earth it would have caused local devastation, like a nuclear detonation.
But according to Dr David Tholen of the University of Hawaii: "Asteroid 1998 DK36 is nothing to lose sleep over. It is the ones we have not found yet that are of concern."