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berkeman
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So I have a quick question which is hopefully still on-topic for the OP's thread...renormalize said:Quadrupole.
In my simplified scenario below, would the splitting hemispheres be considered a dipole, or somehow a quadrupole? If only a dipole, how would the change in gravitation propagate away from the explosive splitting event? Thanks.
berkeman said:To try to give you a better physical scenario and also make it easier to visualize, suppose that the Sun exploded all of a sudden and broke into two hemispheres that flew apart at high velocity, with the 2 halves moving perpendicular to the Solar System's orbital (ecliptic) plane.
The change in the Sun's gravitational field would propagate outward at the same velocity as the light from the Sun, so the changes in the gravitational field from the Sun would be "noticed" on Earth at the same time that we "saw" the two hemispheres separating and flying apart.