Spaghettification vs. length contraction - which one wins?

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Offline LeeE

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YABHS (Yet Another Black Hole Scenario)

You are an observer watching an object falling into a BH.  As it accelerates it will appear to contract in length, in accordance with GR.  However, at the same time, it will start to lengthen due to spaghettification.

Does this mean that you could end up seeing an object moving at relativistic speed but with no apparent foreshortening?

Working out the foreshortening factor is easy enough but I'm not so sure about the spaghettification lengthening factor to work out if they cancel.  The fact that both phenomenom arise from the same and equal cause suggests that they might but this would seem to contradict GR.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline LeeE

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Spaghettification vs. length contraction - which one wins?
« Reply #1 on: 04/07/2008 00:55:17 »
Okay - we can postulate an immensely huge rocket (lots of fuel) that slowy approaches a BH.  It's great mass will not make it accelerate more quickly than a lighter rocket, so spaghettification would seem to dominate over foreshortening.  This isn't a free-fall siituation though - energy is being supplied and must be accounted for.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline DoctorBeaver

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Spaghettification vs. length contraction - which one wins?
« Reply #2 on: 04/07/2008 06:35:15 »


I dunno. I'm just a dumb rodent
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