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Suppose object X is hidden somewhere on Earth and can, somehow, produce "weak" gravitational waves, that do not cause anything perceivable by people, but can be detected by all gravitational wave sensors on Earth. (I understand it's impossible due to mass issues, but just suppose it happened by a currently unknown phenomena, a detectable gravitational wave was produced on Earth by some not yet developed technology, despite being currently impossible for us.)

QUESTION: Would it be possible to triangulate the location of object X, by analysis of the gravitational waves it produced?

If yes, could you give me a brief description of how it would be done? If not, why not? What would be needed to triangulate this position?

This would be for a short story. It has an impossible element (the wave being produced on Earth), but the reaction to the situation has to be plausible. Thank you for helping. :)

peterh
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Anne Mae
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2 Answers2

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Yes it would, though you need at least three detectors so we couldn't do it right now. It would be possible when more GW detectors are commissioned, and indeed more detectors are being built as I type.

The way you do this is by measuring the times the wave arrives at the detectors. Gravitational waves travel at the speed of light, so if for example the wave arrives a microsecond later at detector B than at detector A you know the distance from the source to B must be $300$m greater than the distance from the source to A. That difference of $300$m is the time difference of $1\mu$s multiplied by the speed of light. With enough detectors you can work out where the source is from the different distances to the detectors.

John Rennie
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QUESTION: Would it be possible to triangulate the location of object X, by analysis of the gravitational waves it produced?

Gravitational waves to be detectable, need enormous masses in asymmetric distributions, as for example the gravitational waves detected by the LIGO experiment. "Triangulation" gave an approximate location of the source, with astronomical distances.

No masses at the center of the earth will give detectable gravitational waves, due to the, comparatively with heavenly bodies . very small masses and the weak nature of gravitational interactions.

anna v
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