An explanation for the shift in an asteroid's orbit around the Sun due to a thermal thrust caused by the body's uneven heating by sunlight. The illuminated side of an asteroid absorbs the sunlight and heats up. After a short delay produced by thermal inertia, the asteroid re-radiates the thermal energy and this causes a recoil spin that pushes the asteroid away from its current orbital path. In 2003, scientists used radar data from the Arecibo Observatory of Asteroid 6489 "Golevka" to obtain the first-ever measurements of the Yarkovsky Effect. (Named for the Russian engineer who came up with the idea around the year 1900. )