Once you see the event, wouldn't the gravity waves have already passed? Like a shock wave at the leading edge of an atomic explosion, the other energies follow the initial burst.
seems simplistic to model gravity waves on 3d versions of wave amplitudes on a 2d surface...
if the universe has 11 dimensions, and we include darkmatter to balance out the equations, then a gravity wave may propagate in a way which our simple physics can't compute....
So then: like a single ant can't move a beetle, but an army of ants can; a single particle can't move the moon, but a heavy mass (think about Earth) surely can move the moon and many smaller objects around it.
"Could this explanation unify Newton's & Einstein's models?"
The strong forces may be folding the nearest space-time between the particle and the 'far-away'-space-time, which is more 'loose'. And this loose far-away-space-time is still being affected by the tension of the strong forces, but these looks so weak because the tremendous space-time that they are affecting.
LOL I am gonna say something that might not make sense to any of you but anyways there is a place at work that i always walk by and when i stop in that place everything around me is in slow motion and as if time is slowed down i dont know if time goes slower there or what but i have gotten a friend to stand in the same location and he hasnt notice anything i have only noticed it a couple of times but it only lasts for about 3 minutes and well i cant explain it but time is different pace there
I've never heard of this before but I just wanted to point out that if you were in a "bubble" that made everything around you appear to be moving in "slow motion" then this "time bubble" would actually be speeding time up for you (not slowing it down). Time is all relative to the observer. While to you everything would appear slow, to everything else you would appear to be moving faster. So a bubble with this effect would in fact be accelerating time for the space within it.
That makes sense and I have walked into alot of these bubbles in my life im only 28 and I already have white hair. I dont know maybe I figured it out in the future but time is really messed up for me now like I sometimes see shit on the news about things that just happened but I seen it couple of months ago. I think I messed up by steeping into some worm hole but im coming into some money and im gonna donate 250,000 to DR Ron Mallet so he can work on his time machine or shall i build my own?
i always thought gravity was just the result of a mass in spacetime. put something there, the spacetime around it has to make room . ya know? plz comment
Oscillations in mass would appear as a gravity wave, but in effect its just space dealing with or accommodating matter/mass. In my feeble idea gravity is not a wave as suggested by this nor is it an atomic particle i.e gravitron. I would like to see how varying mass and different shapes warp space in truth.
I would envision the opposite. Mass does not displace space(time) but actually is needed to create spacetime. Except, I think I heard energy can bend space if it is intense enough.
time would move faster in SPACE than on EARTH. gravity slows time, so the higher the gravitational field the slower time moves relative to an area of lesser gravity.
as for the video...i have more hope for lisa...some reason detecting gravity waves OUTSIDE of a gravity well makes more sense to me
fucking morrons you are just some ignorant people trying to look smart and cant come up with anything new imbeciles who can not see the world trying to explain everything in the same same old way and that`s why you will never be able to do it ...
If you look at galaxy, you understand that in the galaxy energy is denser as outside the galaxy . When you go galaxy inside and you look at star, you understand remote in the star energy is denser as because of outside. In the atoms' cores energy is denser as atomic outside the core . Energy in protons / neutron is denser as their outside, and so on. Outside the visible macrocosm, is energiconcentration in which energy much denser as in the visible macrocosm.
Even if one arm is perpendicular to the line pointing to the moon and the other arm is parallel to it? OK, let's build a small interferometer on a vertical turntable, spin it at it's resonant frequency and see if we actually see a gravity-induced change in the speed of light between the arms. It can even have four arms, for balance! Money is obviously no object!
Maybe you're right. I don't think a resonant system would be necessary though with such a strong signal. I wonder what length change we would be looking for ? Time for some research.
Besides, we already have a wonderful 'gravity wave' detector. It's called 'tides'. I feel pretty safe in assuming that the H2O molecules in the oceans move quite a bit further than a nuclear width.
A third of a billion dollars spent on LIGO, but it can't even see the MOON???
are the tides due to water or magma? who can tell? we suspected in 1991 that the tides are em resonance effect on molten metal...far greater than the movement of water. What do you think?
Just one problem - the spacetime interval is frame invariant. Which means that you can't use a local speed of light measurement in an inertial frame to detect changes in interferometer arm length (or, equivalently, changes in light speed). That would mean that the laws of physics change according to gravitational intensity which would violate Relativity.
I take this one back. LIGO isn't looking for changes in light speed and there isn't a violation of Relativity. I do wonder how they settled on a 26 pound mass for the mirrors, though.
This assumes (and I hate to point this out because of the careers involved) that the speed of light is independent of the space it travels in. If the light stretches and compresses along with the space (likely) then measurement becomes impractical with this device. There is a way to measure gravity waves directly, however, thanks to an improved understanding of basic electronics principles that most electronic repair technicians would know about.
I don't think that LIGO will ever detect a GW. I'm not sure if I can explain.
The clue is in that guy playing with the plastic mesh.
From our perspective (outside the mesh), it changes aspect. From the perspective of the mesh, it does not. It's still 10 squares x 10.
Einstein gave us the reason when he talked about a body approaching c. Its aspect changes but from that body's perspective, nothing's changed. Am I making sense or not ? Can someone who knows help me out? BabyEngineer ?
I think I know what you're getting at. The way I see the question is - if the light beam travels through spacetime, won't the beam itself be stretched by exactly the same factor as the distance between the mirrors, and still return with the original phase. I'm still trying to sort this one out.
I have another video that may have some bearing on this: "Why Brooklyn Is Not Expanding". If the expansion of the universe is not causing the distance between the Earth and Moon to increase, then will a gravitational wave cause the distance between the LIGO mirrors to change ?
The distance between Earth and her moon is determined because Luna is in orbit of Earth. Tie two balls together with string and repeat the process so that you have a number of pairs so constructed. Hold in the hand and throw them all.
Those which are tied by string remain tied, yet because there is no tie between each pair, they expand like our Universe.
This represents the collections of orbital systems racing away from each other. Those bodies which are orbitally tied, remain orbitally tied. The space expands, the celestial bodies aren't growing (from our perspective) and nor are their orbits.
Perhaps the whole idea is that the position of the test masses (the mirrors) does <b>not</b> change. The interferometer will then measure only the interaction of the gravitational wave with the light beams.
Interesting idea, but from the way I understand it, they're talking about the entire fabric of the Universe being deformed. If space-time is deformed, everything is, yes ?
Like drawing a face on a balloon then blowing up that balloon. The whole face expands. This is not the same as an expanding Universe. A whole pile of balloons drifting away from each other would represent an expanding Universe.
To clarify, although it's an interesting idea, it's not what is claimed in the clip you uploaded. Watch the little animation with the explanation of why it's laid out in an L shape.
Hahaha... I just watched the clip you recommended.
Coincidentally, he also said that a balloon being blown up doesn't represent an expanding Universe for exactly the reasons I stated. The way he puts it is that the dots would also expand. To me, that represents an expansion of time-space, not an expansion of the physical volume of the Universe.
Its interesting that the "phantom force" only exists because the expansion of the universe is accelerating. If the expansion was linear, there would be no force at all.
That's what the latest supernova data shows. It's why the concept of "dark energy" was invented (thought to be caused by quantum fluctuations in empty space) - it exerts a negative pressure which conteracts the gravitational attraction.
As you say, that's not Weiss' explanation. What it comes down to is - if spacetime is deformed, how does it effect the position of test masses, and how does it effect light ?
All we can do is speculate, experiment, observe and try to work out what the results mean.
However, I don't think that they spent tax-payer's money on a 4km x 4km MI on a whim. They must have a reasonably solid understanding of what they are doing and what they expect to achieve.
I'm trying to understand why my interpretation of 'space-time fabric' differs from theirs (which it MUST do because I'd never have built such a device for that purpose based on my interpretation).
The way I interpret this is that the mirrors are two fixed points in space. When the gravitational wave arrives, it curves the space between the mirrors, so that there is more distance between them, and the path length of the light beams is greater.
how can fixed mirrors measure any changes. The reason I ask is because as space expands, so does time, so the time it takes to traverse the expanded space should be the same as the less expanded space because as the space expands so does the time correlated with it. Space expands, time speeds up..so in that regard it would seem to me the sped up time in the expanded space would arrive at the same time as the non expanded space.
This is tricky. The question here is, what does the interferometer indicate? It measures the difference in arrival times of the two beams. A light beam follows the path of zero proper time - if the spacetime is curved, the path of the beam is also curved. If the curvature on the two paths is different, then an arrival time difference will be detected.
The light beams are always observed to have a velocity c. If the path lengths of the two beams are different, then the propagation times of the beams are also different.
Right after posting my question I remembered that c is constant.....although I still have a hard time swallowing the constancy of em waves. So then would the lights arrive at different times or would there be a red/blue shift with both lights arriving at the same time?
I think we all struggle with the constant speed of light :) It means here that the propagation time is proportional to the path length, so for different path lengths the arrival times are different. There is also a doppler shift as the path length changes when the GW is passing.
If you could see a change in the propagation times of light in that manner, we would have been seeing a variation in the speed of light of about 24.8 hours period in every interferometer throughout the world for the past 100 years.
The arm length seems to be the critical factor. Simulation of the LISA observatory with an arm length a million times that of LIGO show best sensitivity between about 0.002Hz to 0.02Hz.
Well, even so, you'd think that an instrument that should detect changes down to a fraction of an atomic nucleus width should be affected by the strongest signal in our neighborhood, that causes entire oceans to rise and fall! I wonder if they can build an interferometer that is resonant at 11.2 microHz, just as a proof of concept?
It is sensitive to the condition where one arm increases in length, while the other decreases in length. This would be characteristic of a GW passing perpendicular to the plane of the detector. It makes sense that it would be most sensitive when the arm length is equal to the wavelength of the GW.
ohh, god! so? if you guys found and calculate grav. waves so what's the benifit? ha? youre just wasting youre time on this worthless theory. leave that damn gravity alone for god's sake.!!
reading these conversations i suddenly feel very stupid. lol argueing over the amount of matter inbetween galaxies ive never heard of that, they must've been like professors or something.
Light is stuck on the space-time field like a boat on water. Light would appear to slow down when it travels through a galaxy. Then in a way a galaxy is larger then what we can "observe" b/c the entire thing is compressed by itself. I don't know why but It sort of reminds me of dark matter. Is there any connection?
Yes - if the light wavefront is approx flat before it encounters the galaxy, it will become concave as the part of the wavefront near the center of the galaxy lags behind. This will eventually bring the wavefront to a focus, causing the gravitational lensing effect.
I don't think its correct to say the galaxy is really larger - we just have a different viewpoint to an observer within the galaxy. The dark matter connection is that it causes almost all of the space-time distortion because it makes up about 85% of the mass.
I've never understood why the scientific community has never simply accepted that maybe their estimate of how much matter is in the universe is wrong. My feeling is that it's not "dark" matter, it's just regular matter that they hadn't calculated on. As has been said, space is not empty. There's all kinds of matter floating out there. Why not accept that there might be billions of tiny atoms floating around between galaxies that are too small for them to count?
This is a tricky subject. Its known that most of the mass in a galaxy is "dark matter" because the total mass can be calculated from the rate of rotation around the center, and the visible matter only accounts for a small part of the mass. If the "dark matter" was ordinary matter it would affect the rate of cooling of the galaxy, I think.
I have a hard time believing that we can verify the location of each black hole & star in a given galaxy. It has to be an approximation (room for error). Plus there's matter between galaxies that we can't see unless light or radiation passes behind/through it. I know clouds of dust and gas have been seen that way, but what if the gas/dust isn't dense and doesn't block/alter the light enough to be seen? There's a lot of space out there for it to be spread out amongst...
I know what you mean about the significance of matter between the galaxies - I've always felt that its overlooked. There's a good YT video "Unfolding the Universe's Dark Matter" which shows how matter is distributed over cosmic scales.
So not only is time relative but distance is relative as well? Now this is very interesting. So will light "move" faster in a less compressed space compared to a more compressed space? Or will light hold a "constant" speed? In other words, will light slow down (from an outside perspective) when it travels through a galaxy? Or will it seem to keep the same speed?
Very interesting! I found it particularly interesting that gravitational waves needed a way to be explained as being "known" throughout the Universe at the same time. I imagine that it is like Light. At the speed of Light time stops so that Light is therefore everywhere that it ever has been, or ever will be... right NOW.
Your wasting your time and money,. I discovered what gravity was in 1992.
look at gravity wave of the future 3
1234ToddgMr 2 months ago in playlist gravitational waves
Why not configure the tubes perpendicular, with one pointing toward the center of the earth?
seanmPWH 2 years ago
see the video "gravity interferometer"
seanmPWH 2 years ago
Once you see the event, wouldn't the gravity waves have already passed? Like a shock wave at the leading edge of an atomic explosion, the other energies follow the initial burst.
RuffleTheTeacher 2 years ago
And with that thought, I guess we need to build a device to perdict when a GRB is going to happen so we can point our cameras at it in advance.
RuffleTheTeacher 2 years ago
In the models would'nt the waves move inward towards a body? Or is that too simplistic
1stBoster 2 years ago
You know, it almost sounds like shes saying LEGO.
DizzyDemo 2 years ago
interesting vid
interesting discussion in commentary
especially the one two years ago...
seems simplistic to model gravity waves on 3d versions of wave amplitudes on a 2d surface...
if the universe has 11 dimensions, and we include darkmatter to balance out the equations, then a gravity wave may propagate in a way which our simple physics can't compute....
at the moment :)
happyseaurchin 2 years ago
So then: like a single ant can't move a beetle, but an army of ants can; a single particle can't move the moon, but a heavy mass (think about Earth) surely can move the moon and many smaller objects around it.
"Could this explanation unify Newton's & Einstein's models?"
haha, it's too late... I'm gonna sleep.
felix780 2 years ago
The strong forces may be folding the nearest space-time between the particle and the 'far-away'-space-time, which is more 'loose'. And this loose far-away-space-time is still being affected by the tension of the strong forces, but these looks so weak because the tremendous space-time that they are affecting.
felix780 2 years ago
LOL I am gonna say something that might not make sense to any of you but anyways there is a place at work that i always walk by and when i stop in that place everything around me is in slow motion and as if time is slowed down i dont know if time goes slower there or what but i have gotten a friend to stand in the same location and he hasnt notice anything i have only noticed it a couple of times but it only lasts for about 3 minutes and well i cant explain it but time is different pace there
makoshark26 2 years ago
I've never heard of this before but I just wanted to point out that if you were in a "bubble" that made everything around you appear to be moving in "slow motion" then this "time bubble" would actually be speeding time up for you (not slowing it down). Time is all relative to the observer. While to you everything would appear slow, to everything else you would appear to be moving faster. So a bubble with this effect would in fact be accelerating time for the space within it.
Risket 2 years ago
That makes sense and I have walked into alot of these bubbles in my life im only 28 and I already have white hair. I dont know maybe I figured it out in the future but time is really messed up for me now like I sometimes see shit on the news about things that just happened but I seen it couple of months ago. I think I messed up by steeping into some worm hole but im coming into some money and im gonna donate 250,000 to DR Ron Mallet so he can work on his time machine or shall i build my own?
makoshark26 2 years ago
i always thought gravity was just the result of a mass in spacetime. put something there, the spacetime around it has to make room . ya know? plz comment
SeaTownTrouT 2 years ago
Oscillations in mass would appear as a gravity wave, but in effect its just space dealing with or accommodating matter/mass. In my feeble idea gravity is not a wave as suggested by this nor is it an atomic particle i.e gravitron. I would like to see how varying mass and different shapes warp space in truth.
TTTopGun 2 years ago
I would envision the opposite. Mass does not displace space(time) but actually is needed to create spacetime. Except, I think I heard energy can bend space if it is intense enough.
ewmegoolies 2 years ago
Comment removed
master1140 2 years ago
time would move faster in SPACE than on EARTH. gravity slows time, so the higher the gravitational field the slower time moves relative to an area of lesser gravity.
as for the video...i have more hope for lisa...some reason detecting gravity waves OUTSIDE of a gravity well makes more sense to me
tuseroni 2 years ago
Yeah your right, don't know what the hell I was thinking about 2 months ago:P Thanks for pointing out my mistake.
master1140 2 years ago
So even the empty vacuum of space is made of something?
toggsuk 2 years ago
Can gravity be distorted???? Placed some where else??
hannigan06 2 years ago
Now, apply this idea to the coalesence of two black holes at the center of the Milky Way and.... well, um....
(Sigh) I hate being right.
RuffleTheTeacher 2 years ago
It applies perfectly unlike "..... well, um...." that would apply well to "like you-know whateva"
Simiload 2 years ago
don't waves cause oftentimes things to come up on shore?
elizabethjamespenyla 3 years ago
fucking morrons you are just some ignorant people trying to look smart and cant come up with anything new imbeciles who can not see the world trying to explain everything in the same same old way and that`s why you will never be able to do it ...
clubber001 3 years ago
He says as he types on his computer made possible by QM...as he uses his GPS made possible by GR. Are these the same old ways?
anarchopinko 3 years ago
What a long way we are from understanding gravity.
LifesVoyager 3 years ago 4
because making waves would consume energy |!
zloben9000 3 years ago
This comment has received too many negative votes show
this is a STUPID IDEA..
if there were waves there would be resistance and the MOON WOULD FALL DOWN !
zloben9000 3 years ago
WHERE IS DOWN?
hahaaaahahahahahahaaaaa!
iMBBonlyone 2 years ago
If you look at galaxy, you understand that in the galaxy energy is denser as outside the galaxy . When you go galaxy inside and you look at star, you understand remote in the star energy is denser as because of outside. In the atoms' cores energy is denser as atomic outside the core . Energy in protons / neutron is denser as their outside, and so on. Outside the visible macrocosm, is energiconcentration in which energy much denser as in the visible macrocosm.
Etimespace 3 years ago
You do not need alot of mass rember as at the speed of mass goes to infinity
airc123 3 years ago
2 dimentional to measure a 3 dimentiona?
Yea space is contracted and expanded in all directions. The GW is not polerized!
airc123 3 years ago
newton is/was correct
albert is wrong.
billions to prove newton wrong
the cost of apple to prove him correct.
gravity radiates from the atom,
if it sounds to good to be wrong
chances are it ain't.
allentazwell 3 years ago
? Every prediction made by GR has been confirmed - this will be the last one. What are you talking about. How does gravity radiate from an atom?
anarchopinko 3 years ago
Even if one arm is perpendicular to the line pointing to the moon and the other arm is parallel to it? OK, let's build a small interferometer on a vertical turntable, spin it at it's resonant frequency and see if we actually see a gravity-induced change in the speed of light between the arms. It can even have four arms, for balance! Money is obviously no object!
r06u3AP 4 years ago
Interesting - an Earth detector !
Maybe you're right. I don't think a resonant system would be necessary though with such a strong signal. I wonder what length change we would be looking for ? Time for some research.
BrunoTheQuestionable 4 years ago
Besides, we already have a wonderful 'gravity wave' detector. It's called 'tides'. I feel pretty safe in assuming that the H2O molecules in the oceans move quite a bit further than a nuclear width.
A third of a billion dollars spent on LIGO, but it can't even see the MOON???
Tell me this isn't a government project!
r06u3AP 4 years ago
are the tides due to water or magma? who can tell? we suspected in 1991 that the tides are em resonance effect on molten metal...far greater than the movement of water. What do you think?
vhbeazel 3 years ago
I have to retract that earlier statement, I now have a better understanding of how the system works. My apologies.
r06u3AP 3 years ago
Just one problem - the spacetime interval is frame invariant. Which means that you can't use a local speed of light measurement in an inertial frame to detect changes in interferometer arm length (or, equivalently, changes in light speed). That would mean that the laws of physics change according to gravitational intensity which would violate Relativity.
r06u3AP 4 years ago
I take this one back. LIGO isn't looking for changes in light speed and there isn't a violation of Relativity. I do wonder how they settled on a 26 pound mass for the mirrors, though.
r06u3AP 3 years ago
the speed of light is anything but constant!
morningrunner123 4 years ago
This assumes (and I hate to point this out because of the careers involved) that the speed of light is independent of the space it travels in. If the light stretches and compresses along with the space (likely) then measurement becomes impractical with this device. There is a way to measure gravity waves directly, however, thanks to an improved understanding of basic electronics principles that most electronic repair technicians would know about.
themanyone 4 years ago
could we keep the light in the tube like a ping-pong ball ?
scarysky 4 years ago
So that's how UFOs do it.
stang46l 4 years ago
I don't think that LIGO will ever detect a GW. I'm not sure if I can explain.
The clue is in that guy playing with the plastic mesh.
From our perspective (outside the mesh), it changes aspect. From the perspective of the mesh, it does not. It's still 10 squares x 10.
Einstein gave us the reason when he talked about a body approaching c. Its aspect changes but from that body's perspective, nothing's changed. Am I making sense or not ? Can someone who knows help me out? BabyEngineer ?
RoadRunnerLaser 4 years ago 6
I think I know what you're getting at. The way I see the question is - if the light beam travels through spacetime, won't the beam itself be stretched by exactly the same factor as the distance between the mirrors, and still return with the original phase. I'm still trying to sort this one out.
BrunoTheQuestionable 4 years ago
Yes, Bruno. That's exactly what I am getting at.
Surely, the boffins must have some answer for this. I don't think that I'm so smart that I'm the only person to have considered this issue.
RoadRunnerLaser 4 years ago
I have another video that may have some bearing on this: "Why Brooklyn Is Not Expanding". If the expansion of the universe is not causing the distance between the Earth and Moon to increase, then will a gravitational wave cause the distance between the LIGO mirrors to change ?
BrunoTheQuestionable 4 years ago
The distance between Earth and her moon is determined because Luna is in orbit of Earth. Tie two balls together with string and repeat the process so that you have a number of pairs so constructed. Hold in the hand and throw them all.
Those which are tied by string remain tied, yet because there is no tie between each pair, they expand like our Universe.
RoadRunnerLaser 4 years ago
This represents the collections of orbital systems racing away from each other. Those bodies which are orbitally tied, remain orbitally tied. The space expands, the celestial bodies aren't growing (from our perspective) and nor are their orbits.
RoadRunnerLaser 4 years ago
Perhaps the whole idea is that the position of the test masses (the mirrors) does <b>not</b> change. The interferometer will then measure only the interaction of the gravitational wave with the light beams.
BrunoTheQuestionable 4 years ago
Interesting idea, but from the way I understand it, they're talking about the entire fabric of the Universe being deformed. If space-time is deformed, everything is, yes ?
Like drawing a face on a balloon then blowing up that balloon. The whole face expands. This is not the same as an expanding Universe. A whole pile of balloons drifting away from each other would represent an expanding Universe.
RoadRunnerLaser 4 years ago
To clarify, although it's an interesting idea, it's not what is claimed in the clip you uploaded. Watch the little animation with the explanation of why it's laid out in an L shape.
RoadRunnerLaser 4 years ago
Hahaha... I just watched the clip you recommended.
Coincidentally, he also said that a balloon being blown up doesn't represent an expanding Universe for exactly the reasons I stated. The way he puts it is that the dots would also expand. To me, that represents an expansion of time-space, not an expansion of the physical volume of the Universe.
RoadRunnerLaser 4 years ago
Its interesting that the "phantom force" only exists because the expansion of the universe is accelerating. If the expansion was linear, there would be no force at all.
BrunoTheQuestionable 4 years ago
It's accelerating ???
That just goes to show how little I know.
I thought that it was decelerating !!!
RoadRunnerLaser 4 years ago
That's what the latest supernova data shows. It's why the concept of "dark energy" was invented (thought to be caused by quantum fluctuations in empty space) - it exerts a negative pressure which conteracts the gravitational attraction.
BrunoTheQuestionable 4 years ago
Really ?
That's a new one on me.
I'm going to have read up on that. Cheers.
RoadRunnerLaser 4 years ago
As you say, that's not Weiss' explanation. What it comes down to is - if spacetime is deformed, how does it effect the position of test masses, and how does it effect light ?
BrunoTheQuestionable 4 years ago
I think, therein, lies the crux of the matter.
I don't think that anyone really KNOWS.
All we can do is speculate, experiment, observe and try to work out what the results mean.
However, I don't think that they spent tax-payer's money on a 4km x 4km MI on a whim. They must have a reasonably solid understanding of what they are doing and what they expect to achieve.
RoadRunnerLaser 4 years ago
I'm trying to understand why my interpretation of 'space-time fabric' differs from theirs (which it MUST do because I'd never have built such a device for that purpose based on my interpretation).
RoadRunnerLaser 4 years ago
These questions are firmly in the realm of General Relativity, which is quite well established ! I think this requires further study.
BrunoTheQuestionable 4 years ago
I agree that it requires further study and I think, so do they - as evidenced by LIGO.
No-one builds an enormous MI just for fun...
Except me, perhaps... ;)
Thanks to whoever it was who gave my initial comment a thumbs up. Och, I feel quite proud now *sniff*...
RoadRunnerLaser 4 years ago
I found a good reference that seems to provide the answer.
web DOT syr DOT edu/~dmalling/gr DOT html
(Don't get too bogged down in the maths)
BrunoTheQuestionable 4 years ago
The way I interpret this is that the mirrors are two fixed points in space. When the gravitational wave arrives, it curves the space between the mirrors, so that there is more distance between them, and the path length of the light beams is greater.
BrunoTheQuestionable 4 years ago
how can fixed mirrors measure any changes. The reason I ask is because as space expands, so does time, so the time it takes to traverse the expanded space should be the same as the less expanded space because as the space expands so does the time correlated with it. Space expands, time speeds up..so in that regard it would seem to me the sped up time in the expanded space would arrive at the same time as the non expanded space.
pituala 4 years ago
This is tricky. The question here is, what does the interferometer indicate? It measures the difference in arrival times of the two beams. A light beam follows the path of zero proper time - if the spacetime is curved, the path of the beam is also curved. If the curvature on the two paths is different, then an arrival time difference will be detected.
BrunoTheQuestionable 4 years ago
The light beams are always observed to have a velocity c. If the path lengths of the two beams are different, then the propagation times of the beams are also different.
BrunoTheQuestionable 4 years ago
Right after posting my question I remembered that c is constant.....although I still have a hard time swallowing the constancy of em waves. So then would the lights arrive at different times or would there be a red/blue shift with both lights arriving at the same time?
pituala 4 years ago
I think we all struggle with the constant speed of light :) It means here that the propagation time is proportional to the path length, so for different path lengths the arrival times are different. There is also a doppler shift as the path length changes when the GW is passing.
BrunoTheQuestionable 4 years ago
If you could see a change in the propagation times of light in that manner, we would have been seeing a variation in the speed of light of about 24.8 hours period in every interferometer throughout the world for the past 100 years.
r06u3AP 4 years ago
LIGO is most sensitive to GWs between about 60Hz to 1kHz. A period of 24 hours is WAAAY outside its detection range.
BrunoTheQuestionable 4 years ago
Hmm, that seems strange, why should there be a 60 Hz low frequency response cutoff?
r06u3AP 4 years ago
The arm length seems to be the critical factor. Simulation of the LISA observatory with an arm length a million times that of LIGO show best sensitivity between about 0.002Hz to 0.02Hz.
BrunoTheQuestionable 4 years ago
Well, even so, you'd think that an instrument that should detect changes down to a fraction of an atomic nucleus width should be affected by the strongest signal in our neighborhood, that causes entire oceans to rise and fall! I wonder if they can build an interferometer that is resonant at 11.2 microHz, just as a proof of concept?
r06u3AP 4 years ago
Sounds like an interesting spare time project for RoadRunnerLaser !
BrunoTheQuestionable 4 years ago
It is sensitive to the condition where one arm increases in length, while the other decreases in length. This would be characteristic of a GW passing perpendicular to the plane of the detector. It makes sense that it would be most sensitive when the arm length is equal to the wavelength of the GW.
BrunoTheQuestionable 4 years ago
ohh, god! so? if you guys found and calculate grav. waves so what's the benifit? ha? youre just wasting youre time on this worthless theory. leave that damn gravity alone for god's sake.!!
untungsky 4 years ago
**ohh, god!**
**for god's sake!!**
here comes the godamn creationist....the plague and hindrance to scientific development...
snickhill 4 years ago
reading these conversations i suddenly feel very stupid. lol argueing over the amount of matter inbetween galaxies ive never heard of that, they must've been like professors or something.
GlassHalfEmpty23 4 years ago
Why doesn't everyone who is fighting just STOP IT NOW
Vikkie7 4 years ago
Light is stuck on the space-time field like a boat on water. Light would appear to slow down when it travels through a galaxy. Then in a way a galaxy is larger then what we can "observe" b/c the entire thing is compressed by itself. I don't know why but It sort of reminds me of dark matter. Is there any connection?
WhatIsGod 5 years ago
Yes - if the light wavefront is approx flat before it encounters the galaxy, it will become concave as the part of the wavefront near the center of the galaxy lags behind. This will eventually bring the wavefront to a focus, causing the gravitational lensing effect.
BrunoTheQuestionable 5 years ago
I don't think its correct to say the galaxy is really larger - we just have a different viewpoint to an observer within the galaxy. The dark matter connection is that it causes almost all of the space-time distortion because it makes up about 85% of the mass.
BrunoTheQuestionable 5 years ago
I've never understood why the scientific community has never simply accepted that maybe their estimate of how much matter is in the universe is wrong. My feeling is that it's not "dark" matter, it's just regular matter that they hadn't calculated on. As has been said, space is not empty. There's all kinds of matter floating out there. Why not accept that there might be billions of tiny atoms floating around between galaxies that are too small for them to count?
FlaPanther33781 4 years ago
This is a tricky subject. Its known that most of the mass in a galaxy is "dark matter" because the total mass can be calculated from the rate of rotation around the center, and the visible matter only accounts for a small part of the mass. If the "dark matter" was ordinary matter it would affect the rate of cooling of the galaxy, I think.
BrunoTheQuestionable 4 years ago
...Unless the extra matter is held within the supermassive black holes in the galaxy where it's not visible to us.
FlaPanther33781 4 years ago
Its possible to calculate the mass of the black hole from the speed of the nearby stars.
BrunoTheQuestionable 4 years ago
I have a hard time believing that we can verify the location of each black hole & star in a given galaxy. It has to be an approximation (room for error). Plus there's matter between galaxies that we can't see unless light or radiation passes behind/through it. I know clouds of dust and gas have been seen that way, but what if the gas/dust isn't dense and doesn't block/alter the light enough to be seen? There's a lot of space out there for it to be spread out amongst...
FlaPanther33781 4 years ago
I know what you mean about the significance of matter between the galaxies - I've always felt that its overlooked. There's a good YT video "Unfolding the Universe's Dark Matter" which shows how matter is distributed over cosmic scales.
BrunoTheQuestionable 4 years ago
Cool, I'll check it out. Thanks :o)
FlaPanther33781 4 years ago
So not only is time relative but distance is relative as well? Now this is very interesting. So will light "move" faster in a less compressed space compared to a more compressed space? Or will light hold a "constant" speed? In other words, will light slow down (from an outside perspective) when it travels through a galaxy? Or will it seem to keep the same speed?
WhatIsGod 5 years ago
Very interesting! I found it particularly interesting that gravitational waves needed a way to be explained as being "known" throughout the Universe at the same time. I imagine that it is like Light. At the speed of Light time stops so that Light is therefore everywhere that it ever has been, or ever will be... right NOW.
AllaBest 5 years ago
An observer moving at close to the speed of a gravity wave would see the universe shrink in the direction of motion ...
Of course, from our frame of reference a gravity wave does have a propagation time - this aspect of Newton's theory was incorrect.
BrunoTheQuestionable 5 years ago