If an object were to threaten
Earth, it would only be necessary
to move the object by one Earth
radius, a very small distance in
space terms. One idea
suggested for a smaller asteroid
is to anchor a shuttle-type engine
onto the moving space rock and
gently speed it up or slow it
down. Another possible strategy
would be to attach solar sails to
a potentially hazardous body and
allow the gentle pressure of
sunlight to deflect the threatening
asteroid away from Earth.