"Doug Miller" wrote in message
What part of "one and a half million miles a day" are you having
trouble understanding?

If you are chasing another car at 100 MPH on a straight road across
Texas neither the car nor the horizon appears to move. Likewise an
object approaching along the line of Earth's orbital path may not
shift enough to notice against the starfield.
http://en.wikipedia.org/wiki/Blink_comparator