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Revision as of 04:23, 18 September 2003 by 66.43.232.185 (talk)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)A tractor beam is a hypothetical device (such as by the Death Star in the Star Wars movies) used at certain lengths with a field intensity beam that "locks" on to an object and can attract that object. On the Starship Enterprise on the television show Star Trek, it is part of the deflector dish and employs graviton particles, the theoretical particles that cause gravity. The Enterprise's beam can also be used to repel objects.
An obvious problem to be overcome if a tractor beam is to be viable: Mass-Mass interaction between the source and target objects. If the object emitting the beam (source object) is significantly more massive (e.g. a planet v.s. a ship) than the targeted object, then the tractor beam will draw the target toward it.
However, if the two objects are of similar mass, then the laws of momentum conservation state that both objects will move toward their mutual center of gravity, with the more massive object moving a smaller distance. Center-of-Gravity and momentum concepts are explained in most Physics 101 textbooks within the first ten chapters.
Final note: In the case of a planet-ship interaction, the planet is so much more massive than the ship that it's motion may be disregarded, as it essentially doesn't move (with respect to the center-of-gravity). A similar case is when dealing with star-planet interactions (the star is way more massive than a planet).