NASA's Wide-field Infrared Survey Explorer, or WISE, has spotted its first never-before-seen near-Earth object (NEO), the first of hundreds it is expected to find during its mission to map the whole sky in infrared light.
NEOs are asteroids and comets with orbits that pass relatively close to Earth's path around the sun. In extremely rare cases of an impact, the objects may devastate the Earth's surface.
An asteroid, about 10 km wide, is thought to have plunged into our planet 65 million years ago, triggering a global disaster and obliterating dinosaurs.
However, there is no danger of the newly-discovered asteroid hitting the Earth, designated 2010 AB78, after discovery by WISE in the second week of January.
"This is just the beginning," said Ned Wright, the mission's principal investigator from University of California Los Angeles (UCLA). "We've got a fire hose of data pouring down from space."
The mission's sophisticated software picked out the moving object against a background of stationary stars. As WISE circled the Earth, scanning the sky above, it observed the asteroid several times during a period of 36 hours before it moved away.
Researchers then used the University of Hawaii's 2.2-metre visible-light telescope near the summit of Mauna Kea to follow up and confirm the discovery.
The asteroid is currently about 158 million km from the Earth. It is estimated to be roughly one km across and circles the sun in an elliptical orbit tilted to the plane of our solar system.
The object comes as close to the sun as Earth, but because of its tilted orbit, it will not pass very close to the Earth for many centuries. Additional asteroid and comet detections will continue to come from WISE, said a NASA release.
The observations will be automatically sent to the clearinghouse for solar system bodies, the Minor Planet Center in Cambridge, Massachusetts, for comparison against the known catalogue of solar system objects.