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How to Detect Extra Dimensions

PBS Space Time · 1.6M views · 2018-10-03 · 15:48

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Overview

A PBS Space Time episode on how gravitational wave observations of a neutron star merger, GW170817, can limit the number of spacetime dimensions. It is based on a 2018 paper.

On Hacker News

HN points to it as a clear explanation of the evidence that gravity does not propagate into extra dimensions.

Recommended by 3 HN people across 1 months · HN mentions 2018–2020

Topics

Cosmology & astrophysicsFundamental physics
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gravitational wavesgw170817cosmologypbs space timegeneral relativity

What people said

dwaltrip · 2018-10 · Recommendation

Well, it has a gravitational effect, so it definitely exists inside of our normal spacetime. Scientists have explored alternative models of gravity or spacetime with additional spatial dimensions and things like that. As far as I know, none of them are very promising. There was an interesting PBS space time video about one example recently: [VIDEO] Of course, it is definitely interesting to think about :)

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stephengillie · 2018-10 · Recommendation

The problem is that gravity, like EM, follows an inverse-square rule. If gravity had a 4th dimensional component, we would expect to see an inverse-cube situation. The equation is: 1/(1-dimensions) Youtube video that explains this in depth: [VIDEO]

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Twisol · 2018-10 · Recommendation

For what it’s worth, evidence has come out (explained well by this PBS Space Time episode [1]) that makes the “gravity propagates over more than three spatial dimensions” theory a bit less likely. [1] [VIDEO]

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Sources

Video by PBS Space Time, played through YouTube.

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