A dangerously large asteroid could hit the earth in 2182 - and it needs to be deflected by 2080 at the latest, according to a global research team.
Scientists from NASA's Jet Propulsion Laboratory and European universities estimated and monitored potential impacts usingtwo mathematical models.
They found that asteroid (101955) 1999 RQ36 has a one-in-a-thousand chance of impacting the Earth, most probably in the year 2182. Knowing this may help deflect it.
It was discovered in 1999 and is around 560m in diameter.
Because of the asteroid's erratic orbit, opportunities to deflect it are limited, says the team. It approaches the Earth closely between 2060 and 2080, again in 2162, and 2182 is the most likely year for the collision.
"The consequence of this complex dynamic is not just the likelihood of a comparatively large impact, but also tha a realistic deflection procedure - path deviation - could only be made before the impact in 2080, and more easily, before 2060," says María Eugenia Sansaturio, co-author of the study and a researcher at Universidad de Valladolid.
"If this object had been discovered after 2080, the deflection would require a technology that is not currently available."
She warns that current impact monitoring does not cover more than 80 or 100 years, and that eforts should be made to ensure that in future they can encompass more than one century.