Today I Learned
The Yarkovsky Effect and YORP Effect
Yarkovsky Efffect1: Asteroids obsorbs sunlight, heated up by the light and emmits thermal radiation. The thermal radiations can produce a tiny force but accumulated through decades to change the orbit of asteroids of size less than 30 - 40 km.
YORP Effect1: Similarly the reflection of sunlight and thermal radiation can cause a torque on the small objects.