Small and seemingly harmless changes in the amount of sunlight hitting an asteroid over time can actually alter its course. This phenomenon is better know as the Yarkovsky effect, after the Russian civil engineer who published a pamphlet around 1900 describing this now very important occurrence. It is thanks to the Yarkovsky effect that scientists can now make extremely accurate measurements of an asteroids trajectory, taking into account even the tiny but important changes caused by sunlight.
The path of asteroids and how sunlight impacts them was the topic of a recent presentation at the “Asteroids, Comets, and Meteors 2012″ meeting in Japan where scientists discussed the planned mission to asteroid RQ36. The mission, “Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx),” involves sending a probe to land on the asteroid and then return to Earth with a sample. Being able to take into account the Yarkovsky effect allows for the extremely accurate measurements that will be needed for the probe to successfully reach RQ36 in the year 2019.
How good are the current measurements? According to Christopher Crockett of EarthSky, “Repeated observations in 1999, 2005, and 2011, using the Arecibo and Goldstone radio telescopes, refined the 30 million kilometer closest approach distance to an accuracy of about 300 meters!”
Photo: Dave Makes / flickr