What would happen if I were 1 ly from a black hole merger?

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Discussion Overview

The discussion revolves around the effects of gravitational waves from a black hole merger on a person located 1 light year away. Participants explore the implications of gravitational wave interactions, including potential physical distortions and the nature of sound perception in such conditions. The scope includes theoretical considerations, mathematical reasoning, and speculative scenarios.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant calculates that at 1 light year from a black hole merger, the deflection would be approximately 9 meters over 4 kilometers, leading to significant physical stretching.
  • Another participant suggests that molecular bonds in the body would resist such compression and expansion, but expresses uncertainty about the overall effects.
  • A later reply proposes that the amplitude of gravitational waves varies linearly with distance, leading to a revised calculation of 3 nanometers of deflection at 1 light year.
  • Questions are raised about how sound perception might be affected by spacetime distortion, including potential shifts in pitch and temperature changes due to molecular vibrations.
  • One participant speculates on the isotropy of gravitational wave effects and the possibility of directional jolts from the merger.
  • Another participant corrects their earlier post, noting that oscillations in time and space would not alter the perception of sound notes.
  • Concerns are expressed about the mathematical assumptions being made, particularly regarding the relationship of deflection to distance, with one participant recalling a 1/r relationship instead of 1/r².
  • One participant reflects on the small effects of gravitational waves despite the massive energy involved in black hole mergers, emphasizing the weakness of gravity.

Areas of Agreement / Disagreement

Participants express varying interpretations of the effects of gravitational waves, with no consensus reached on the calculations or implications. Multiple competing views remain regarding the nature of gravitational wave interactions and their physical consequences.

Contextual Notes

Participants acknowledge limitations in their calculations and the potential oversight of General Relativity in their reasoning. There is also uncertainty regarding the assumptions made about the behavior of gravitational waves and their effects on physical bodies.

Pete Muller
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I was reading about the latest black hole merger discovered by LIGO.

https://www.ligo.caltech.edu/news/ligo20170601

The article states that the deflection of the arms over 4km was 1×10^-18 meters for an event 3 billion light years (ly) away. If I assume that gravitational waves follow the inverse square law, then at 1 ly the deflection would be 9 meters over the same 4km. More importantly to me, it would be about 4mm over my 1.8 meter height. I would think that would be highly unpleasant!

Worse, at 0.1 ly the effect would be 100 times greater so I would stretch 0.4 meters. Not going to survive that!

So, is my math correct?
 
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That's an interesting question. If I understand things correctly, this "compression" and "expansion" are opposed by the molecular bonds making up your body, explaining why the LIGO experiments often talk about the strain of their detectors. Alas I'm not actually sure what would happen. Perhaps curling up into a ball would help?
 
How much is eardrum deflected by 1 db sound?
 
snorkack said:
How much is eardrum deflected by 1 db sound?

If space time is distorted would the pitch oscillate? For instance "middle a" tone would shift to A sharp and A flat/G sharp? The change might be too fast to register in the brain.

Drakkith said:
That's an interesting question. If I understand things correctly, this "compression" and "expansion" are opposed by the molecular bonds making up your body, explaining why the LIGO experiments often talk about the strain of their detectors. Alas I'm not actually sure what would happen. Perhaps curling up into a ball would help?

Temperature is based on vibrations in molecular bonds. I would expect a distortion oscillation of space could alter the effective temperature. I am not sure that hot cold and back to normal at light speed would change anything. Just speculation but maybe something that was super cooled and ready to freeze or super heated and ready to boil might make the phase transition. Might also effect the activation energy for some chemical reactions. The probability of tunneling events?
 
Will it be isotropic ? Or concentrated in the merger plane ??
Be nasty if there's a planar jolt plus a polar outburst...
 
My post was wrong. If time and space oscillate the both the hairs in the cochlea and the sound wave will oscillate. The hair(s) that registers the note "A" will still resonate in all parts of the gravity wave. Would not hear anything odd.
 
Pete Muller said:
If I assume that gravitational waves follow the inverse square law,
I seem to recall that the deflection follows a 1/r relationship, not the 1/r2.

Oh -you have already noted that in #3
 
I extrapolated to 1 million km and got 28 mm for LIGO and about 13 micrometers for me. Clearly I am pushing the math here not to mention ignoring General Relativity. But still, the amazing thing is that 2 solar masses were converted to gravitational energy and the effect is so small. Gravity truly is weak!
 

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