In addition to tonight's full Christmas moon and the Christmas Comet's trip across the sky, yet another celestial body will be available to view on Dec. 24, Christmas Eve: an asteroid will be making a flyby 6.7 million miles above the Earth's surface.
Named both 163899 as well as 2003 SD220, the asteroid is projected to be roughly 0.43 miles in diameter (though earlier sightings first reported it as much as 0.8 miles) and travels at a rate of five miles per second.
Here are delay-Doppler images of 2003 SD220 as observed by us at @NAICobservatory these past few nights. pic.twitter.com/iOMXOIiOBy
— Arecibo Radar (@AreciboRadar) December 8, 2015
"The 2015 apparition is the first of five encounters by this object in the next 12 years when it will be close enough for a radar detection. By obtaining radar ranging measurements at each observing opportunity, it may be possible to detect non-gravitational perturbations due to the Yarkovsky effect. If so, then we can obtain an estimate of the object's mass, information that is invaluable for understanding the object's bulk density and internal structure."
As for the importance of NASA's asteroid observation during its Christmas Eve flyby? As Popular Science notes, the space agency is thinking of sending astronauts up to 163899's surface one day to explore, so any information they can glean beforehand will make the future mission as smooth as possible.
If you miss it this time, the first of the asteroid's next 12 flybys is slated for December 2018.
Via: Popular Science
