Arecibo Observatory has observed near-Earth asteroid (NEA) 2003 SD220, which will have its closest approach to Earth on December 24. Although designated as “potentially hazardous,” this asteroid will be 28 times further away than our Moon and therefore poses no present danger to Earth. There is neither chance of impact nor any other effects due to its flyby.
The NASA-funded planetary radar system at Arecibo measured 2003 SD220 to be very elongated and more than 2 km (1.25 miles) long. It also rotates very slowly, taking more than 11 days to complete one full rotation.
If this size asteroid hit the earth then the impact energy would be about 100,000 megatons. This would make a 12 mile wide crater. This size of asteroid hits the earth once every million years.
The NASA Jet Propulsion Laboratory’s Goldstone Solar System Radar and the National Radio Astronomy Observatory’s Green Bank Telescope and Very Long Baseline Array also conducted observations of 2003 SD220. Data from all of these observations are used to determine the asteroid’s shape, rotation, and surface properties as well as allow for refinement of the asteroid’s orbit, which can be used to better assess its impact hazard.
This year’s close approach is the first of five predicted encounters between Earth and 2003 SD220 in the next twelve years. High-precision measurements now will help better prepare for future passes.