InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
An Earth starship has been sent to check an Earth outpost on the planet P1407, whose moon houses a battle group of the often hostile Reptulians. As the ship follows a straightline course first past the planet and then past the moon, it detects a high-energy microwaveburst at the Reptulian moon base and then, 1.10 s later, an explosion at the Earth outpost, which is 4.00xx10^(8) m from the Reptulian base as measured from the ship's reference frame. The Reptulians have obviously attacked the Earth outpost, and so the starship begins to prepare for a confrontation with them. Did the burst cause the explosion, or vice versa? |
|
Answer» Solution :KEY IDEA The sequence of events measured in the planet-moon reference FRAME is the reverse of that measured in the ship frame. In either situration, if there is a causal RELATIONSHIP between the two events, information MUST travel from the location of one event to the location of the other to cause it. Checking the speed: Let us check the required speed of the information. In the ship frame, this speed is `v_("info")=(Deltax)/(Deltat)=(4.00xx10^(8)m)/(1.10s)=3.64xx10^(8)m//s, ` but the speed is impossible because it exceeds c. In the planet-moon frame, the speed comes but to be `3.70xx10^(8)m//s`, also impossible. Therefore, neither event could POSSIBLY have caused the other event, that is, they are unrelated events. Thus, the starship should STAND down and not confront the Reptulians. |
|