An asteroid is heading for a close encounter with Earth and could come closer than some orbiting satellites.
Scientists say there is no need to panic because it will miss the Earth by at least 15,000 miles.
Asteroid TX68 was spotted three years ago by astronomers in the US
The rock, which is 30 metres wide (100ft) and named 2013 TX68, was spotted three years ago by astronomers in the US scouring the skies for potentially threatening near-Earth objects (NEOs).
Because the asteroid was tracked for only 10 days, its orbital path is uncertain. Experts believe it will make its closest approach to Earth on Sunday, although the forecast might be one or two days out.
Calculations show that 2013 TX68 could shoot past the Earth well within the ring of geostationary communications and GPS satellites stationed 22,300 miles above the equator. At the other limit of its predicted range, it could remain as far out as 40 times the distance to the moon.
The US astronomer Sean Marshall, from Cornell University in New York, who studies NEOs, such as comets and asteroids, said: “Should this asteroid come closer than the geostationary satellites, it would be a rare occurrence – that only happens about once per decade for large asteroids.
“What we know for sure is that it will not collide with Earth this month, so do not panic.”
He said it was extremely unlikely that it would hit a satellite. “TX68’s trajectory will take it on an arc through a huge region of space, and satellites are very small objects.An asteroid hitting a satellite would be like a blindfolded person throwing a pebble and hitting a single small needle in an enormous haystack.”
He said the asteroid had “absolutely no chance” of colliding with the international space station, which circles the Earth at an altitude of about 250 miles.