Radar image of asteroid 2005 YU55. Image credit: NASA/Cornell/Arecibo

Kind of following up Marian’s post about asteroids, scientists at JPL have “imaged” the near-earth asteroid 2005 YU55 using the Arecibo Radar Telescope in Puerto Rico back on April 19, 2010.

Orbital track of 2005 YU55. Courtesy JPL

The asteroid at one time was listed as a potential threat because its orbital path brings it very close to Earth on occasion, a few passes of which could not be ruled out for possibility of impact.  It takes a number of observations to be able to predict an orbit.  It follows that the predictions can only be as accurate as the observed position.  You can appreciate when looking through a telescope how difficult it can be to get a very precise position.  Sure you can get very close but even a small error can add up over a long distance.

With the Arecibo Radar Telescope the scientists were able to track the asteroid with very fine accuracy.  The image above was take on April 19, 2010 and while described as ghostly (which it is) the resolution is 25 feet (7.5 meters) per pixel, not bad for an object 1,300 feet (400 meters) across.  The asteroid also appears spherical in shape.  By tracking the asteroid from April 19th to the 21st , scientists were able to reduce the uncertainties in the orbit by half and we know there no chance of a collision for at least 100 years.  More observations will enable longer term predictions.

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