"Solar sails would thus be especially useful for journeys to distant planets or vastly more distant stars"
But, as the distance from Sun increases, light intensity DECREASES as SQUARE of distance.
When the sail reaches half way to another star, Sun will push it almost as much as that star (ok, a bit less because of difference in reflection).
Slashdot Mirror
"Solar sails would thus be especially useful for journeys to distant planets or vastly more distant stars" But, as the distance from Sun increases, light intensity DECREASES as SQUARE of distance. When the sail reaches half way to another star, Sun will push it almost as much as that star (ok, a bit less because of difference in reflection).