maybe I was wrong when I accused you of knowing everything......you surely missed out on this:
http://en.wikipedia.org/wiki/Centrifugal_force
this applies to changing the weight of the comet as well as changing weights of all orbiting objects, with or without strings attached :)
I still say it wound be wiser to have chosen a comet not integral to our solar system, given the (admittedly small) chance that its mass might be altered sufficient to alter the orbit.
BTW, do you actually bother to type that first line of each of your posts, or do you have some doo-dad that does it automatically?
In the News/Activism forum, on a thread titled *Live Thread* -- 7/3/05 NASA "Deep Impact" Comet, Vn_survivor_67-68 wrote:
"maybe I was wrong when I accused you of knowing everything......you surely missed out on this:
http://en.wikipedia.org/wiki/Centrifugal_force
this applies to changing the weight of the comet as well as changing weights of all orbiting objects, with or without strings attached :)
I still say it wound be wiser to have chosen a comet not integral to our solar system, given the (admittedly small) chance that its mass might be altered sufficient to alter the orbit."
Okay: quick physics lesson. A comet, or any other body orbiting the Sun, has its path determined by the balance between the "centrifugal" force (really inertia) of its motion and the gravitational pull of the Sun and other objects. The path of the comet would be _the same_ whether or not it is in one big piece or lots of little pieces.
So the only danger would be if the impactor probe knocked a piece of the comet off into an orbit which might someday intersect the Earth. As I demonstrated in a previous message, there just isn't enough energy in the impact to make that a danger.
As to your suggestion that it would be wiser to choose a comet "not integral to our solar system": comets are short-lived objects on a stellar timescale. None of them are integral. Hitting a long-period comet in the outer solar system would have required a much bigger rocket, making the mission impossibly expensive.
Look, don't you think the people at NASA _think_ about stuff like this _before_ they launch? "Oh, gee, what if it hits the Earth and kills everyone? Whoops, too late!"