LIGO gravitational wave announcement

GodMark2 said:
No less than 180km (the radius of the resultant black hold post-merger).
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I finally found this that explains in more detail than most searches.

http://www.tapir.caltech.edu/~teviet/Waves/gwave_spectrum.html

I note that LIGO has a detection range around (+ and -) 10^6 meters, although I also note that the wavelength is greater than the causing object, but 180 km is within that lower range.

However since gravity waves do not actually interact with mass or transfer energy to it, it is hard to see how it can actually cause damage to a mass. After all it simply changes, briefly, the space time nature of any mass it passes and we no doubt have those passing through even as we have this discussion.

The only way I can imagine a destructive effect is if the wavelength and amplitude were such that it pulled atoms apart so much that the nuclear forces holding them in their configurations and interactions were disrupted and they turned into some kind of plasma to recombine in unknown ways; but I have no idea if that is even theoretically possible given that the nuclear forces are many many magnitudes stronger than gravity.
 
Yes, but I don't think it really answers the question. It implies that you could but it is so feeble that you wouldn't, which of course we know. But would you if you were closer?
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You cannot be at the same time close enough to feel any tidal forces without being reduced to plasma.
 
macdoc said:
You cannot be at the same time close enough to feel any tidal forces without being reduced to plasma.
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Are tidal forces not capable of operating at various levels of intensity, such that one might feel a slight effect, without being thereby reduced to plasma? Or an event that would reduce a nearby mass to plasma, might have a smaller, but still detectable, effect on a somewhat more distant object?
 
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Maartenn100 said:
"ripples in the fabric of space and time." Nice words, but no human being can really grasp what it means. No scientist can grasp: a big bang, spacetime, quantumphysics, singularities etc. You think you understand these things because you gave it a fancy name. It is beyond our human capacity to actually understand what's going on in this world on these levels. ;)
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It's spacetime, not two separate things added. The fact that you have made this ugly false picture of what General Relativity is about is evidence that you really are ignorant.

Your assertion that all GR does is name things is another indicator that you are blowing raspberries out your arse.

If you had ever bothered to actually take a science course, you would have more respect for the maths. And our limited human conceptual tools are not sufficient to "understand" with a simple image or analogy to things we do understand, that much is true. But the maths is a different story, which can indeed be fully understood.

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Edited to remove breach of rule 0 and rule 12
 
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might have a smaller, but still detectable, effect on a somewhat more distant object?
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This is what we do withi LIGO.. can we "feel it"...under any circumstance where we are not in the volume of space blasted by the energy release - very very unlikely in my view.
 
Craig B said:
Are tidal forces not capable of operating at various levels of intensity, such that one might feel a slight effect, without being thereby reduced to plasma? Or an event that would reduce a nearby mass to plasma, might have a smaller, but still detectable, effect on a somewhat more distant object?
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In a link on this page it noted that being near 2 colliding, 10 solar mass black holes moving at light speed would produce a gravity wave around 1% the size of an atom. Which would obviously be impossible to feel but the tidal forces would be huge.

So to produce a macroscopic gravity wave there would need to be around 10^15 more colliding black holes. So I guess tidal forces and other problems always get in the way.
 
Tests beginning soon on The LISA Pathfinder mission. It's a technology demonstrator for a proposed (but as yet unfunded...) mission to scale up the LIGO measurements. So it's measuring the distance between two free-floating blocks only 38cm apart, but with incredible levels of accuracy.

http://www.bbc.com/news/science-environment-35689814
 
Originally Posted by Craig B View Post
Are tidal forces not capable of operating at various levels of intensity, such that one might feel a slight effect, without being thereby reduced to plasma?
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careful...it's not the gravity wave reducing you to plasma if nearby...it's what caused the gravity wave.....the gravity wave is a consequence of the event.....as is your plasma make over.
 
macdoc said:
careful...it's not the gravity wave reducing you to plasma if nearby...it's what caused the gravity wave.....the gravity wave is a consequence of the event.....as is your plasma make over.
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Why would two orbiting black holes reduce you to plasma?
 
GodMark2 said:
Two Words:

Accretion diskWP
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Do we have reason to think there was an accretion disk?

ETA: And why would the accretion disk cause gravitational waves? (see the post I was replying to if that question doesn't make sense to you).
 
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RecoveringYuppy said:
Do we have reason to think there was an accretion disk?

ETA: And why would the accretion disk cause gravitational waves? (see the post I was replying to if that question doesn't make sense to you).
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There is no evidence one way or other on the accretion disk. And accretion disk would not have any influence on the gravitational waves. The later was caused by the two black holes orbiting very close to each other.
 
rjh01 said:
There is no evidence one way or other on the accretion disk. And accretion disk would not have any influence on the gravitational waves. The later was caused by the two black holes orbiting very close to each other.
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Yes, I agree.
 
RecoveringYuppy said:
Do we have reason to think there was an accretion disk?

<snip>
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We don't.

However, if you were close to the two black holes, you'd be converted to a plasma very quickly indeed, and that plasma would form into a (very thin!) accretion disk (albeit not so quickly).

There may not have been much plasma near the two black holes, in the days leading up to the merger, but what little there was (and there certainly was at least some) would have made your life close to the BHs very uncomfortable indeed. Not to mention getting spaghettified ...:D
 
JeanTate said:
We don't.

However, if you were close to the two black holes, you'd be converted to a plasma very quickly indeed, and that plasma would form into a (very thin!) accretion disk (albeit not so quickly).

There may not have been much plasma near the two black holes, in the days leading up to the merger, but what little there was (and there certainly was at least some) would have made your life close to the BHs very uncomfortable indeed. Not to mention getting spaghettified ...:D
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Yeah, I get that. My post was questioning macdocs scenario. He said the even that causes the gravity (think he meant gravitational) waves would also turn you to plasma. I don't know why that would be.

The phenomena you're talking about doesn't require orbiting black holes and happens even in the absence of gravitational waves.

So I'm not sure what connection macdoc is referring to.
 
He said the even that causes the gravity (think he meant gravitational) waves would also turn you to plasma
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RY...I don't think you understand what the process is.

Very close to two back holes you are going to be plasma but for a different reason....near vicinity is very violent space.

Further out you could in theory orbit the two but a long ways out

In neither case are there gravitational waves produced that we could detect.

When the two black holes merged however...3 solar masses were turned from mass to energy in an instant.

That event produced the gravitational wave we detected .....

That event would ALSO turn your distant orbiting space ship to plasma

.....but it's not the GW turning you stardust ....it's the energy release....equivalent to 50 x the output of all the stars in the universe for a very brief moment. That's the point at which you join the stardust contingent ......but it's not the gravity wave dismembering you .....it's the energy release.

The GW is a result of the change in gravity caused by converting mass to energy on an enormous scale.....3 solar masses worth..
Your dismemberment is a result of the energy release not of effects of the gravity wave on you.
 
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According to these guys at 1AU it would feel more like standing next to a loudspeaker, which if true is pretty awesome (if you're at a concert that is, pretty underwhelming if you're 1AU from a collapsing black hole)
https ://www .reddit.com/r/askscience/comments/45n0sz/how_close_to_gw150914_the_black_hole_merger_would/

(I've broken the link as I'm not allowed to post them yet)
 
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