tar

iNow, I am leaning in StringJunky's direction. Particularly noting how Muhammed brought together the warring idol worshipping tribes. If you are basing your morals on tribal, pack mentality, then one is liable to exactly not be tolerant of someone not in your tribe, stealing your resources and your mates and your gold...unless you have an overarching maker of the rules that is going to judge even kings and emperors. And as for other animals having morals based on the pack. This morning my wife was screaming in panic at the dog who had chased a rabbit across the yard, cornered it against the fence and it died of shock or perhaps it broke its neck. Same dog spent the winter chasing squirrels off the bird feeder at my command. It was a game of sorts, I would hear the woodpecker on the house or see the squirrel on the feeder and I would open the door and the dog would go charging out. She never caught a squirrel as they would dash over the fence or up a tree. I think she was expecting the rabbit to scale the fence. It did not. She killed it. Regards, TAR

no. But phone conversations can be multiplexed more heavily than data lines. And data transfer needs high frequency carrier waves. We only have one main wave with some weak precursors that we don't even know are related, until after the wave is figured. We are only looking at the last gasp of two small in diameter black holes spiraling around each other at .6C. And I have no doubt we can tell a lot about the masses and their spin and speed and how many solar masses are lost in energy to the wave, but I was reversing myself on any hope of finding the signatures of other GWs on the ones we sense. We don't see enough of the wave to see what the wave looks like just 10 miles away. If we had a LIGO every mile for all the distance between this and another one, then we could hope to read the space that the wave traveled through. or how about a LIGO on the center of each of the 12 segments of the sphere, the sphere being Earth never mind about the 12 spots Great in theory because you could figure direction really well and get all sorts of info the width and depth of the earth separation would provide since every station would have a twin on the opposite side of the earth and two stations one 90 degrees to the left and one 90 degrees to the right...except most of the required positions would be in an ocean which would create a whole different wave problem

on further musing I do not think we sense enough of the wavefront to get a good read on the history of the wave as a whole in essence we just get a point in diameter core sample of the shell, just in that one tiny area covered by the experiment, and another thin core sample at the location of the other beam splitter setup for instance, there could be a "dent" in the wavefront that was missed because the dent was in the area of the wave that passed between the experiments or there could be an attribute of the wave front that was missed because the lead edge of the wave front hit the one experiment while it was at amplitude h and it was slightly less or more when it hit the other experiment That is, given a stack of planes of gigantic size to represent the wave front, we have as information only something about a single line, a second long, going through the planes, normal to the wave front. The plane of the wave front hits the other station at a different time, so wavers in the wave between the time it hits station 1 and 2 are not known about. and the beam, before it hits the splitter, is bounced back and forth 500 times or something to leverage the change in the distance between the mirrors, and this will not give us any information about the differences in the gravity wav e that occurred over that entire distance...it would just give us the average of the amplitude of the wave portion that was in the experiment, during the time beam made the trip...but maybe since its continuously read it works out...but seems like since the wave is also going the speed of light...you blink, and you miss something... only take a reading every 500 blinks, you might not have a solid stream of data... could you make heads or tails from every 500th letter in a book?

Perhaps my approach is not great. It is not working out for me at the moment. Some adjustment is required.

Mordred, Your post was beyond me as I am not versed in fourier transforms and guassian stationary backgrounds and the like, but I get the idea, that you could judge, by the characteristics of a GW, something about its history. That is, not only what caused it, but what scattered it, or attenuated it, this way or that way, or interfered with it. Thinking that maybe could allow us to reconstruct a wave that long ago passed through here going south, by reading the signature that it left on the GWcoming from the South that we just read. That way we would not have to wait for a wave to pass through Earth to read it, we could form a mathematical "picture" of all the expanding shells that a GW passed through and draw a model of waves we have not yet seen and that have already passed, just by carefully analyzing one. Regards, TAR and maybe reconstruct a non-stationary background that a wave must have passed through to have the characteristics that it has sort of like getting an x-ray image of space The black holes merging sent a simple very powerful wave out, and we can read the shape of space between by reading what came through. I think I made a mistake in logic there somewhere. We could figure waves that already passed through, but I don't think there is a geometrical way for the signature of a future wave to be on an arriving wave. The mathematical picture we drew would have to imply a future wave, not read its signature... I am confused...expanding shells of one event are difficult to think about, especially on universal scales that we can not easily switch into and out of mentally. Or at least I cannot.

Thread, Thanks to Function, the poster, in Suggestions, I now remember how to post a spoiler. So here is my approach. I think the solution is near by either completing the thought, or adjusting it in some workable manner. Regards, TAR

Function, Thank you for that. My excuse for not knowing how to do it will be a secret between you and me, except for those who want to know. Spoiler alert! Excuse explained here. Regards, TAR

I have forgotten how to post a clue to a puzzle and make it only viewable to those who click on the button.

well right, understood, but when a wave cancels out another, like when you hold your fingers close together and see the black lines, where does the energy go? I am using the sine wave as an analogy to the stress of compression cancelling out the stress of stretching in the orthogonal direction.

Strange, Was wondering about the conservation of energy thing, when I take a square grid and pull on the corners. The diamond shows no sign of wanting to pop back into square shape. It is perfectly satisfied to stay in the new configuration. Somehow, though all the wires and lengths between welds is exactly the same, the welds seem to be balanced in terms of being compressed one way and stretched the other. They perhaps store potential energy, but two portions of the weld are wanting to relax by expanding from being compressed, while the other two opposite portions are wanting to return to their relaxed state by compressing from being stretched. Regards, TAR

Strange, I wonder if what you say about the waves continuing on undisturbed after intersection is completely true. I would imagine that when the sum of the amplitudes of two overlaid sine waves(1/4 wavelength out of phase) is zero there is actually no amplitude. In the case of GW waves I would imagine that means H+ and Hx cancel each other out, annihilate each other, like two antiparticles would. Like gone. In which case the stretching influence, the strain, is relieved. Here is a thing I was working on for my 12 segments of a sphere topic that I never posted because it did not work, as I did not have the curvature of the pieces right, but I post it to show that if you take a square grid of wire and pull on two corners you can get the 75 degree and 105 degree intersection in the middle of the diamond. Shown to show how space might be stressed so the orthogonal direction is decreased as the other orthogonal direction is increased. Also shown to show that the x of the colored threads is 90 degrees offset from the x of the wire grid. Just to visualize 3d intersections of gravity waves which would be basically two planes intersecting at a line. But to the point, after an intersection would both waves, each taken as a spherical shell, be still completely intact or would certain portions of the shell be attenuated or damped by passing through another? Regards, TAR Ignore the grey and pink yarn, it is just used to sew the sections together and has no analog important to the discussion.

Commander, Nice puzzle. I did not solve it yet, but I think I have a good approach. I will post the approach as a hint if you remind me how to post a spoiler. Regards, TAR

"In the case of two isolated black holes, there would be no visible result." But there could be EM results, like some sort of x-ray or gamma ray burst. And after all, a hole is a hole. A mass as dense as a black hole would do something to the light backlighting it. Either lens it, or absorb it. And are not black holes suppose to have fountains of energy spewing out "the poles"? ...but then again if the two holes are so close as to merge, it would be difficult to say what was caused by the one or the other or the both, of the EM variety of evidence. "Rather like shining one light beam though another; it has no effect." Rather odd statement on a thread based on the interference, no signal effect of two halves of a beam coming back together 1/4 wavelength out of phase. that is, one needs to consider what happens to space if two gravity waves are there at the same time, coming in from orthogonal directions

Strange, "How the wave is stretched and compressed as it passes through the zillions of other waves it would have to have navigated in the last 1.3 billion years. " You said there would be no effect, but I think you mean passing through an electromagnetic field type wave would have no effect. I was not thinking of EM waves, I was thinking of GM waves and failed to specify in the sentence. I was envisioning space shaped like the rubber sheet with bowling balls on it with a million gw event firemen holding the sheet. Each tug on the edge of the sheet would ripple through the whole sheet with time. So my zillion waves are ripples of space, the sheet. So the question I was having was, doesn't one gw have to navigate the compressions and rarefactions of space caused by another GW, as well as transverse the gravity wells caused by all masses? That is, if a photon has to stay within the rubber, does not a gravity wave have to as well? Regards, TAR So specifically I am thinking that although we only experience an event a year, that means that there are currently on the order of lets say 100,000 gw shell like wave fronts currently in the Milkyway. Each ripple has to pass through all the other ripples to get to us. Like refraction at the boundary of two substances the angle of incidence of the wave, like the rank of soldiers entering the swamp, would turn the wave. So other masses and other gravity waves, if they indeed are warping space itself, are to be taken into account when considering the path and origin of a GW. At least I would guess.

Strange, We could take it into account, but do we? If we are associating a GW with an optically verifiable mass, and the gravity took a different course though warped space then did the light by which we build the image of the optically verifiable mass, then there is a delay equal to the difference in path length between the image gained optically or by radio wave or x-ray detector, and the image gained by calculating the waves within the chirp. Given the distances involved a different path could mean days or weeks or months or years or decades or maybe thousands of years. So to associate a GW event with a electromagnetic field event, you would have to account for a timing difference and a direction difference. Perhaps analogous to tying a particular clap of thunder echoing off the side of the garage, with a particular flash of lightning lighting up the side of the garage. Regards, TAR

zapatos, Yes, but that is my sort of point about noticing the wave. It is really not tremendously important for you to know which way my television was facing or what channel I was on a particular day, and not only would your speculation be wrong when you pieced together the scarce facts you had into a theory of what happened in that spot, but you would be wrong in two general ways that had little to do with the specific speculations. One, I am accidently retired and was probably not away from the spot the eight hours you are speculating about monitoring, and two, due to the rotation of the Earth and the revolution of the Earth around the Sun and the Sun's revolution around the Milky Way's core, that spot has been vacated by not only my TV but a whole lot of Earth and Solar System. That spot, may or may not be within the Heliosphere by now. Which brings up another point about reconstructing an event that happened so far away, based on one little distortion of the LIGO experiment. We do not know what effect the Heliopause has on a gravity wave. How it attenuates the signal. How the wave is stretched and compressed as it passes through the zillions of other waves it would have to have navigated in the last 1.3 billion years. Does the galaxy have a galaxypause, where a bunch of particles are piled up against the radiation pressure coming in from surrounding galaxies? Do the equations we use subtract the effect that this mass has on the wave and how it attenuates it? What if we are attributing a characteristic of the LIGO signal t o the spin or mass of one of the holes, when the characteristic is an artifact of some other masses, that we are not figuring for? Regards, TAR which brings up another issue a gravity wave is an unstudied creature we theorize it travels through space at the same rate as photons/light but we also theorize it attenuates space itself photons ride on a complex wave through magnetic field orthogonal to electric field where it is hard to imagine what is media and what is message light is bent around massive galaxies as space is curved by the gravity If light is lensed in this way, are gravity waves as well? That is if we figure a gravity wave is coming from the same spot as a galaxy we know is there, or was there by the light, is it certain that the gravity wave would have taken the same route through space to where we can overlay the image of the gw with our image of the galaxy and be sure they actually represent the same event? for instance the time of day the spot on Earth the time of year the angle of the Solar system's equator compared to the center of the galaxy would all be contributory to deciding if the wave was coming in from away from the Milkyway core or through it. And if there is a black hole at the center of our own galaxy, this would have to make a difference in the attitude of the GW. Is all this figured for?

Strange, Sorry it is a vague construction. I guess I mean basically that the universe is extremely large and extremely long lived, and sensing a black hole merger 1.3 billion lys away is quite a shakey proposition. Not that the wave was not caused by the holes merging, but that we cannot tell, from here, what is currently in that spot where the holes merged. We have no way to send out a reporter and take a picture of the event. And if we look at that spot now I suppose we will see a freshly formed massive black hole...but we really don't know a darn thing about what happened in that spot over the last 1.3 billion years. Regards, TAR

so it is important to note that the simulations do not "show" anything that is currently extant in the universe and the picture of two giant holes close to each other, is a picture of what things might have looked like WAY before the merger and not what things looked like during the second before merger in other words, there are not black holes out there merging that we will EVER sense, as if they are out there and we have not found them yet, and once we find them we can take their picture

Strange, The Rate p​aper dealt with the sensitivity of the equipment as well as what signals are to be called GWs to what level of confidence, and ramped up expectations into the future observation cycles based on known or projected sensitivity. That is not how I was looking at it. Given the sensitivity of the system when we saw GW150914, and a guesstimate of the rate of black hole mergers or neutron star collisions, events that could produce a detectable GW across a steady state universe taken all at once, once, all of the events we will ever witness (in the next 100 years) have already occurred, unless an event happens within 100 lys which is not likely unless two neutron stars dash into the area and collide, which would also be the last gw we see. So I was not looking at our ability to detect, but looking at how many are on their way here, and how many have passed, as in if you were anywhere in the universe, how often would a GW, like the three we have seen, come by. Regards, TAR I suppose I don't like the way people think about the universe, because it is not always clear what people are calling now, as I am always arguing for the two now position, and not everybody complies in their thinking, or their descriptions in terms of what they are calling GW150914. Is it the merger, which happened 1.3 billion years ago 1.3billion lys away, or is it the event when the wave passed and we sensed it with LIGO, or is it the wave itself, which still exists and is known presently to the universe as an ever expanding concentric sphere surface a light second thick? in my thinking every black hole merger that ever happened is now a wave in space, that 1 second thick expanding shell On Earth, we are either inside a black whole merger's wave, in which case it already passed, or we are outside the shell in which case the wave is on its way at the speed of light toward us.

studio, Thanks for the full quote, I think I get what Einstein meant when he said, "To this there also belongs the faith in the possibility that the regulations valid for the world of existence are rational, that is, comprehensible to reason." I think that means that to be a scientist and trust in math and natural laws and such you have to trust that objective reality can be counted on, unconditionally. To this there is a direct analogy to "trust in God". Without this faith, that 2 plus 2 will always be 4, science is lame. But without science, without reason and facts and experimentation, there would be nothing of objective reality to actually know . Like you were walking around with your eyes closed, or you were blind to the actual objective reality you had faith in. Regards, TAR So...Science without religion is lame, and religion without science is blind.

The people at Caltech that said "which might occur on a yearly basis within a volume of radius 6×1020km (20 megaparsecs)." That is 6x10(to the 20th)km. The superscript 20 failed to copy over from the link.

SwansonT, The original link in #94 did work and was a nice layout. Thanks. I think I have it now. In terms of frequency of black hole mergers though, I am not sure of the thinking. Let's say for instance we have one going on now at the center of our galaxy, like let's say it happens tomorrow at 6. We would not get the wave for 30,000 years, or however far we are at light speed from the event. However if in 10 nearby galaxies there were 10 incidents that happened and each was exactly as far away as each incident was long ago, we could get all 10 waves next Thursday. So it seems the range of a wave would dictate what volume of space we could expect a wave from, but I do not understand on what basis we are predicting the frequency, or so to speak, if we should expect one or two or three or so every two years. Past performance is no guarantee of future performance. But that is neither here nor there, the thread question is whether LIGO can detect gravity waves, and it appears like it not only can, but did. Three times as a system. What do you think, aramis720? Regards, TAR On the frequency, I am thinking that any black hole mergers in the local area, say within 100million lys, that happened 101million years ago or before...we have already missed. They came through and we didn't have our ears on. And most of those that did happen within the last 100million years are on average still scores of millions of years from getting here and bending our space. So if we think of shells of space at further and further distances, each of a certain thickness in terms of radial distance from here, the volumes of the further shells would be greater and hold more stars and galaxies and if black hole mergers are equally distributed per volume, larger volume shells, would have more mergers. So each shell as you go out would have more candidates, and we should expect more distant than local gws .

well forget the comet question. Comets are just a little dust and gas, not massive at all. But when a planet orbits, I understand that it is in essence, falling around the Sun, or a moon falling around its mother planet. They are accelerating and therefore would have a non zero integral.

swansont, The simulation is way misleading. There are big stars in the foreground and tiny stars further back giving an impression that you are looking at massive in diameter holes with clouds of stars around their perimeter. I would say it is meant to give the impression of a view from 10s of thousands of light ​​years...but hey its a simulation, not worth arguing over, it does not mean anything, there is no real components to it. f But back to the gravity gradient. The link gave me a 404 error so I am just going by your two test mass description, and I am not sure whether the test masses are far from the source of the gradient or the two masses creating the gradient. The strain on the space within the interferometer is what I thought we were measuring, and the distance between the mirrors is not exactly the distance of the path of the beam, because the beam is sent back and forth quite a few times before recombined. So the strain on the mirror at the end of the path and at the leveraging mirrors near the half silvered one, is different at any t only by the gradient between, not the full beam path distance implied gradient. All this is probably figured, but I am concerned as to what we figure the distance between the mirrors means in terms of what happened with the black holes, 1.3 billion years ago. That is, if the gradient between the mirrors squishes the space between the width of a partial proton, and that is because some huge mass was accelerating very close to another huge mass 1.3 billion years ago, wouldn't a comet making its close approach to the Sun cause a little chirp itself? Regards, TAR relativity wise does it matter if the Sun is M1 and the comet is M2? that is can you consider the Sun accelerating toward the comet?