A gentle method of causing an asteroid to miss planet Earth.Will spray paint save the world?Recently, NASA scientists using the giant RADAR telescope in Puerto Rico measured changes in the orbit of the asteroid Bennu. They found that a tiny sunlight pressure of 1/2 oz on this 68 million ton object has changed it's orbit about a hundred miles over a 12 year period of time. These NASA astronomers thus measured the Yarkovsky force which was first suggested by a Russian engineer more than a hundred years ago. This Yarkovsky force, named for its proposer, occurs because sunlight absorbed by an object in space is reradiated in a directional way and thus acts like a tiny rocket motor. It is likely that, over the eons, this tiny effect has changed the course of families of asteroids between Mars and Jupiter causing some of them to be sent in our direction.