In an earlier video, the guy was talking about how gravity bends light i.e. we can see stars behind the sun because the sun’s gravity has bent the light.

Here, he’s talking about gravitational waves and how we’ve only measured them indirectly e.g by observing an object spiralling into something massive (like a black hole) and the energy it’s losing is probably gravitational waves. Also that gravitational waves move through space and seem to affect space so that when a g-wave (my own term) moves over the Earth, space seems to change shape and anything moving through space will also be affected by that g-wave.

So, my question is, when gravity is bending light around a massive object, is that due to g-waves and wouldn’t that also be an observation of said g-waves?

no. the bending of the light is due to light following a “straight” path in bent spacetime.

the bending of the light is due to light following a “straight” path in bent spacetime.

a bit like flying in a plane around the world. according to your instruments you are flying straight and level but you’re not when you consider the shape of the earth.

JudgeMental said:

no. the bending of the light is due to light following a “straight” path in bent spacetime.

In that case I am completely misunderstanding the concept of gravitational waves.

gravity waves are the resulting ripples in spacetime caused by moving bodies.

rubber sheet analogy time. bowling ball resting on it causes a well. dropping the bowling ball on it causes ripples.

So how would say, light behave when travelling through g-waves? it’s bent by the bowling-ball-makes-a-well scenario, or can we not detect light and only “see” EMR?

Didn’t see any Maths

Divine Angel said:

So how would say, light behave when travelling through g-waves? it’s bent by the bowling-ball-makes-a-well scenario, or can we not detect light and only “see” EMR?

A gravitational wave is the manifestation of change in a gravitational field; it’s the field that effects the geometry of space-time.

Thus the wave is the interface between differing geometries.

gravity wave detector use lasers at right angles over long distance to see the resulting change in path length.

JudgeMental said:

Didn’t see any Maths

“ As the neutron stars gain speed, their gravitational wave production increases, leading to further energy loss and further speed-up”

Is this theorised or a known fact i.e. is their energy loss definitely going into increased gravitational waves?

waves

Divine Angel said:

“ As the neutron stars gain speed, their gravitational wave production increases, leading to further energy loss and further speed-up”

Is this theorised or a known fact i.e. is their energy loss definitely going into increased gravitational waves?

There is indirect evidence:

PSR B1913+16 (also known as PSR J1915+1606 and PSR 1913+16) is a pulsar (a radiating neutron star) which together with another neutron star is in orbit around a common center of mass, thus forming a binary star system. In 1974 it was discovered by Russell Alan Hulse and Joseph Hooton Taylor, Jr., of the University of Massachusetts Amherst. Their discovery of the system and analysis of it earned them the 1993 Nobel Prize in Physics “for the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation.”

….The orbit has decayed since the binary system was initially discovered, in precise agreement with the loss of energy due to gravitational waves predicted by Einstein’s general theory of relativity. The ratio of observed to predicted rate of orbital decay to be 0.997±0.002. The total power of the gravitational radiation (waves) emitted by this system presently, is calculated to be 7.35 × 1024 watts. For comparison, this is 1.9% of the power radiated in light by our own Sun. (Another comparison is that our own Solar System radiates only about 5000 watts in gravitational waves, due to the much larger distances and orbit times, particularly between the Sun and Jupiter).

With this comparatively large energy loss due to gravitational radiation, the rate of decrease of orbital period is 76.5 microseconds per year, the rate of decrease of semimajor axis is 3.5 meters per year, and the calculated lifetime to final inspiral is 300,000,000 years.

http://en.wikipedia.org/wiki/Hulse-Taylor_binary

I knew there was indirect evidence, the guy on the video was saying so. The website made it sound like it was an indisputable fact.

Divine Angel said:

I knew there was indirect evidence, the guy on the video was saying so. The website made it sound like it was an indisputable fact.

If I learned anything at all from SSSF it was the only indisputable fact was that we would one day reach the stars!

Dropbear said:

waves

You have abundant gravity…

OCDC said:

Dropbear said:

waves

You have abundant gravity…

e=mc hammer

JudgeMental said:

gravity wave detector use lasers at right angles over long distance to see the resulting change in path length.

What sort of board would you use for gravity waves?

What sort of board would you use for gravity waves?

a long one i guess.

JudgeMental said:

gravity wave detector use lasers at right angles over long distance to see the resulting change in path length.

Why does the gravity wave not affect the light as well as the detectors, cancelling each other out?

the gravity wave “stretches” the distance between the laser source and the mirror producing interference patterns in the detectors.

JudgeMental said:

the gravity wave “stretches” the distance between the laser source and the mirror producing interference patterns in the detectors.

Ok, But since gravity affects light by “bending” light around a star, why does it not affect the photons travelling along the detector?

they are two different things. light bending is due to the geometry of “static” space, the gravity well massive objects cause in spacetime. gravity waves are a changing gravity field. and so cause a changing geometry.

if gravity is a wave

what is its frequency?

the frequency would depend on how fast the source was moving i guess.

is the distortion produced by a gravity wave compression or expansion? Expansion might be harder to detect

JudgeMental said:

the frequency would depend on how fast the source was moving i guess.

yes its a curly one isn’t it?

I’ve heard someone say that that gravity moves at light speed but they couldn’t back that up

lets say it moves at light speed , what frequency would gravity be ?

wookiemeister said:

JudgeMental said:

the frequency would depend on how fast the source was moving i guess.

yes its a curly one isn’t it?

I’ve heard someone say that that gravity moves at light speed but they couldn’t back that up

lets say it moves at light speed , what frequency would gravity be ?

do you mean band width or frequency?

both.

The effect of a plus-polarized gravitational wave on a ring of particles.

The effect of a cross-polarized gravitational wave on a ring of particles.

Riff-in-Thyme said:

wookiemeister said:

JudgeMental said:

the frequency would depend on how fast the source was moving i guess.

yes its a curly one isn’t it?

I’ve heard someone say that that gravity moves at light speed but they couldn’t back that up

lets say it moves at light speed , what frequency would gravity be ?

do you mean band width or frequency?

frequency

all waves have a frequency

JudgeMental said:

they are two different things. light bending is due to the geometry of “static” space, the gravity well massive objects cause in spacetime. gravity waves are a changing gravity field. and so cause a changing geometry.

So the geometry changes after the photon has left the emitter, and before it reaches the detector?

lets say it moves at light speed , what frequency would gravity be ?

like i said it would vary, just like emr does.

if the gravity was travelling in free space with no meaningful distortion by other sources eg a void of some size and the speed of gravity was constant what frequency would the wave have?

one would assume that the further from the source the gravity wave would lose concentration very much in the same way as the light from a lightbulb or sun

kingy, yes. the laser is going all the time. distance is known to a accurate extent. gravity wave passes through the machine and alters the distance between the laser – mirror – detector.

wookiemeister said:

if the gravity was travelling in free space with no meaningful distortion by other sources eg a void of some size and the speed of gravity was constant what frequency would the wave have?

The same frequency as the source.

If the black holes were circulating at 1000rpm, then that would be the frequency.

Kingy said:

wookiemeister said:

if the gravity was travelling in free space with no meaningful distortion by other sources eg a void of some size and the speed of gravity was constant what frequency would the wave have?

The same frequency as the source.

If the black holes were circulating at 1000rpm, then that would be the frequency.

I’m not convinced

the sun rotates it doesn’t dictate the frequency of the light

does anyone know what the frequency of gravity is?

wookiemeister said:

does anyone know what the frequency of gravity is?

Ask Kenneth, he knows the frequency.

the sun rotating is not producing significant gravity waves. there would be some miniscule ones from the interaction with the planets but i reckon they would be next to impossible to detect.

gravity doesn’t have a frequency.

wookiemeister said:

Kingy said:

wookiemeister said:

if the gravity was travelling in free space with no meaningful distortion by other sources eg a void of some size and the speed of gravity was constant what frequency would the wave have?

The same frequency as the source.

If the black holes were circulating at 1000rpm, then that would be the frequency.

I’m not convinced

the sun rotates it doesn’t dictate the frequency of the light

that is because the suns rotation doesn’t create the light where the pulsars does

from what I’m looking at they’ve got the wrong end of the stick

measuring the distance between a light source and mirror doesn’t measure frequency of a gravity wave at all

it just measures the concentration of the gravity or volume of the gravity wave

as far as I can see they’ve got diddly squat

JudgeMental said:

kingy, yes. the laser is going all the time. distance is known to a accurate extent. gravity wave passes through the machine and alters the distance between the laser – mirror – detector.

But the photons travel at C, just like the gravity wave. This is where my understanding of it falls over. I can’t see how there would be a difference between the photons path and the emitter/mirror/detector path. It may be explained in the link that you posted earlier but I haven’t had time to read it.

The sun-earth system likely produces exceedingly weak gravity waves, wookie. Immeasurably weak.

A single body does not produce a gravity wave.

Riff-in-Thyme said:

wookiemeister said:

Kingy said:

The same frequency as the source.

If the black holes were circulating at 1000rpm, then that would be the frequency.

I’m not convinced

the sun rotates it doesn’t dictate the frequency of the light

that is because the suns rotation doesn’t create the light where the pulsars does create the gravity wave

if gravity had a true frequency rather than just volume then you could create a gravitational frequency generator in 180 deg out of synch with the frequency of gravity

then you’d have a antigravity device

star wars speeder style

you’d need a device that could speed up and slow particles within a doughnut shaped vessel

the vessel would be nuclear powered of course

I’m suggesting that “wave “ is the wrong word, its more like volume

the volume of gravity – there I’ve coined a phrase

I’m sorry miss

your gravity is too big – I can’t hear you

that always goes down well

wookiemeister said:

I’m suggesting that “wave “ is the wrong word, its more like volume

the volume of gravity – there I’ve coined a phrase

amplitude is the term

the distance changes so therefore the photons path changes. this will cause interference patterns as the wave either reinforce or cancel. the dector, the bit you are interested in the most is the preferred frame of reference in the experiment and so is “stationary”.

wookiemeister said:

I’m suggesting that “wave “ is the wrong word, its more like volume

the volume of gravity – there I’ve coined a phrase

So if you go to a party in a black hole, they turn the volume up to eleven?

Riff-in-Thyme said:

wookiemeister said:

I’m suggesting that “wave “ is the wrong word, its more like volume

the volume of gravity – there I’ve coined a phrase

amplitude is the term

yeah I know but I like “volume”

Kingy said:

wookiemeister said:

I’m suggesting that “wave “ is the wrong word, its more like volume

the volume of gravity – there I’ve coined a phrase

So if you go to a party in a black hole, they turn the volume up to eleven?

whoa

gravity police, turn down that black hole

Kingy said:

wookiemeister said:

I’m suggesting that “wave “ is the wrong word, its more like volume

the volume of gravity – there I’ve coined a phrase

So if you go to a party in a black hole, they turn the volume up to eleven?

yeah that is way better than ten

this will cause interference patterns as the wave either reinforce or cancel. the dector, the bit you are interested in the most is the preferred frame of reference in the experiment and so is “stationary”.

this will cause interference patterns as the waves either reinforce or cancel. the detector, the bit you are interested in the most, is the preferred frame of reference in the experiment and so is “stationary”.

fixed.

JudgeMental said:

the distance changes so therefore the photons path changes. this will cause interference patterns as the wave either reinforce or cancel. the dector, the bit you are interested in the most is the preferred frame of reference in the experiment and so is “stationary”.

I’m gonna have to admit that I don’t understand it enough to comprehend how the detector works, but thanks for trying, Boris.

one of the ideas I’ve had is that in the future we will be able to blow up black holes by appearing a device into the heart of the black hole to deconstruct it explosively

its how we’ll save the universe from the threat of roaming black holes

we’ll simply be changing mass into energy and vica versa in a sustainable and renewable way

there will be no end of the universe – its against our interests

I enjoy gravity discussions. It’s like everyone is milling about looking for a fight but can’t get confrontatinal traction. :D

Kingy said:

JudgeMental said:

the distance changes so therefore the photons path changes. this will cause interference patterns as the wave either reinforce or cancel. the dector, the bit you are interested in the most is the preferred frame of reference in the experiment and so is “stationary”.

I’m gonna have to admit that I don’t understand it enough to comprehend how the detector works, but thanks for trying, Boris.

they are assuming that gravity waves will attract the detector and emitter as they pass by

a big assumption

wookiemeister said:

Kingy said:

JudgeMental said:

the distance changes so therefore the photons path changes. this will cause interference patterns as the wave either reinforce or cancel. the dector, the bit you are interested in the most is the preferred frame of reference in the experiment and so is “stationary”.

I’m gonna have to admit that I don’t understand it enough to comprehend how the detector works, but thanks for trying, Boris.

they are assuming that gravity waves will attract the detector and emitter as they pass by

a big assumption

attract?

wookiemeister said:

one of the ideas I’ve had is that in the future we will be able to blow up black holes by appearing a device into the heart of the black hole to deconstruct it explosively

its how we’ll save the universe from the threat of roaming black holes

we’ll simply be changing mass into energy and vica versa in a sustainable and renewable way

there will be no end of the universe – its against our interests

you push the beast into a type of criticality and turn the mass into energy – big bang stay clear

they are assuming that gravity waves will attract the detector and emitter as they pass by

no.

instead of posting crap and things you think are so how about reading and learning?

the biggest problem will be somehow deflecting the Andromeda galaxy that’s about to hit us

the only thing I can think of to stop this happening is to appear an artificial gravity source near Andromeda to draw it towards that rather than us

then as it approached the gravity source you turn it off and Andromeda passes by without destroying us

wookiemeister said:

Kingy said:

JudgeMental said:

the distance changes so therefore the photons path changes. this will cause interference patterns as the wave either reinforce or cancel. the dector, the bit you are interested in the most is the preferred frame of reference in the experiment and so is “stationary”.

I’m gonna have to admit that I don’t understand it enough to comprehend how the detector works, but thanks for trying, Boris.

they are assuming that gravity waves will attract the detector and emitter as they pass by

a big assumption

(sigh)

JudgeMental said:

instead of posting crap and things you think are so how about reading and learning?

as I said I think they’ve got the wrong end of the stick

gone

when do you file the patent for your ‘appearing’ mechanism? sounds handy

In this case, the minimum distance to find waves is R ≈ 1 light-year, so typical amplitudes will be h ≈ 10−26. That is, a ring of particles would stretch or squeeze by just one part in 1026. This is well under the detectability limit of all conceivable detectors.
http://en.wikipedia.org/wiki/Gravitational_wave

wookie is H.G.Wells

which is what i said about the sun planets. even without reading it on wiki.

wookiemeister said:

In this case, the minimum distance to find waves is R ≈ 1 light-year, so typical amplitudes will be h ≈ 10−26. That is, a ring of particles would stretch or squeeze by just one part in 1026. This is well under the detectability limit of all conceivable detectors.
http://en.wikipedia.org/wiki/Gravitational_wave

10^26 is not 1026
It is one part in 100000000000000000000000000.

Riff-in-Thyme said:

wookie is H.G.Wells

not really

I follow all logical routes to the inevitable conclusion as it presents

it might be that “aliens” are from either this galaxy or Andromeda or elsewhere and are seeing what we come up with to save our galaxy

its scouting out to see whats ticking in the brain box of various organisms or thinking machines

the heart of the organic machine is sentimental and will try to save the galaxy – the machine will simply pull up stumps and go elsewhere?????

Kingy said:

wookiemeister said:

In this case, the minimum distance to find waves is R ≈ 1 light-year, so typical amplitudes will be h ≈ 10−26. That is, a ring of particles would stretch or squeeze by just one part in 1026. This is well under the detectability limit of all conceivable detectors.
http://en.wikipedia.org/wiki/Gravitational_wave

10^26 is not 1026
It is one part in 100000000000000000000000000.

go and argue with wiki typo

wookiemeister said:

Riff-in-Thyme said:

wookie is H.G.Wells

not really

I follow all logical routes to the inevitable conclusion as it presents

it might be that “aliens” are from either this galaxy or Andromeda or elsewhere and are seeing what we come up with to save our galaxy

its scouting out to see whats ticking in the brain box of various organisms or thinking machines

the heart of the organic machine is sentimental and will try to save the galaxy – the machine will simply pull up stumps and go elsewhere?????

i was referring to your terminology-appearing device, gravity volumisation etc. The stretches of your imagination are more Escher……

wookiemeister said:

Kingy said:

wookiemeister said:

In this case, the minimum distance to find waves is R ≈ 1 light-year, so typical amplitudes will be h ≈ 10−26. That is, a ring of particles would stretch or squeeze by just one part in 1026. This is well under the detectability limit of all conceivable detectors.
http://en.wikipedia.org/wiki/Gravitational_wave

10^26 is not 1026
It is one part in 100000000000000000000000000.

go and argue with wiki typo

Gosh!

Riff-in-Thyme said:

wookiemeister said:

Riff-in-Thyme said:

wookie is H.G.Wells

not really

I follow all logical routes to the inevitable conclusion as it presents

it might be that “aliens” are from either this galaxy or Andromeda or elsewhere and are seeing what we come up with to save our galaxy

its scouting out to see whats ticking in the brain box of various organisms or thinking machines

the heart of the organic machine is sentimental and will try to save the galaxy – the machine will simply pull up stumps and go elsewhere?????

i was referring to your terminology-appearing device, gravity volumisation etc. The stretches of your imagination are more Escher……

what could be better?

wookiemeister said:

Riff-in-Thyme said:

wookiemeister said:

not really

I follow all logical routes to the inevitable conclusion as it presents

it might be that “aliens” are from either this galaxy or Andromeda or elsewhere and are seeing what we come up with to save our galaxy

its scouting out to see whats ticking in the brain box of various organisms or thinking machines

the heart of the organic machine is sentimental and will try to save the galaxy – the machine will simply pull up stumps and go elsewhere?????

i was referring to your terminology-appearing device, gravity volumisation etc. The stretches of your imagination are more Escher……

what could be better?

it takes all sorts

Riff-in-Thyme said:

wookiemeister said:

Riff-in-Thyme said:

i was referring to your terminology-appearing device, gravity volumisation etc. The stretches of your imagination are more Escher……

what could be better?

it takes all sorts

I think that given a few more brains and a different throw of the dice and the absence of people trying to injure me and kill me in the past……….. now its all just buggered. in these circumstances you’ve got to have a hobby to keep you amused.

wookiemeister said:

Riff-in-Thyme said:

wookiemeister said:

what could be better?

it takes all sorts

I think that given a few more brains and a different throw of the dice and the absence of people trying to injure me and kill me in the past……….. now its all just buggered. in these circumstances you’ve got to have a hobby to keep you amused.

I take it you’ve never conquered the known world only to discover the hollowness of the victory. You can’t look back to go forward

You can’t look back to go forward
—————————-
What about rowing???

Riff-in-Thyme said:

wookiemeister said:

Riff-in-Thyme said:

it takes all sorts

I think that given a few more brains and a different throw of the dice and the absence of people trying to injure me and kill me in the past……….. now its all just buggered. in these circumstances you’ve got to have a hobby to keep you amused.

I take it you’ve never conquered the known world only to discover the hollowness of the victory. You can’t look back to go forward

kneels down and takes a handful of dirt and rubs it between my fingers

victory is mine!

Stealth said:

You can’t look back to go forward
—————————-
What about rowing???

What? You know how much oaries get paid? They face backward cause they’ll never have anything to look forward to.

wookiemeister said:

Riff-in-Thyme said:

wookiemeister said:

I think that given a few more brains and a different throw of the dice and the absence of people trying to injure me and kill me in the past……….. now its all just buggered. in these circumstances you’ve got to have a hobby to keep you amused.

I take it you’ve never conquered the known world only to discover the hollowness of the victory. You can’t look back to go forward

kneels down and takes a handful of dirt and rubs it between my fingers

victory is mine!

just make sure you wash your hands before dinner sweetheart……

> when gravity is bending light around a massive object, is that due to g-waves and wouldn’t that also be an observation of said g-waves?

This is probably already answered above. Gravitational waves, like ocean waves, are a time-dependent phenomena. The gravitational bending of light by a massive object is a steady-state phenomenon, so cannot be said to be an observation of gravitational waves.

mollwollfumble said:

> when gravity is bending light around a massive object, is that due to g-waves and wouldn’t that also be an observation of said g-waves?

This is probably already answered above. Gravitational waves, like ocean waves, are a time-dependent phenomena. The gravitational bending of light by a massive object is a steady-state phenomenon, so cannot be said to be an observation of gravitational waves.

I thought about this and I think I finally understand. For some reason, I had it stuck in my head that waves were constant, even though the concept of water waves says otherwise. I was stuck thinking that even though one wave moves, there’s always waves. Once I got around that mental block, gravitational waves made sense (finally :p )

so you’re pretty well up on what grav waves etc are now? from a layman POV of course.

JudgeMental said:

so you’re pretty well up on what grav waves etc are now? from a layman POV of course.

Yes. It’s at the limits of my smarts, but the good news is that my smarts limits are being stretched :) Kingy’s comments about detectors is answered with a simple “it just is” and ATM that’s good enough for me!

As a result of passing this short course, they’ve recommended the next step (should I wish to further in this field) is Physical Sciences majoring in Physics… I think I’ll give that one a miss :)

Divine Angel said:

JudgeMental said:

so you’re pretty well up on what grav waves etc are now? from a layman POV of course.

Yes. It’s at the limits of my smarts, but the good news is that my smarts limits are being stretched :) Kingy’s comments about detectors is answered with a simple “it just is” and ATM that’s good enough for me!

As a result of passing this short course, they’ve recommended the next step (should I wish to further in this field) is Physical Sciences majoring in Physics… I think I’ll give that one a miss :)

But think of all the calculus you’ll be missing out on!

I’m already missing calculus, the dentist cleaned it all off last week.

http://www.icrar.org/news/news_items/media-releases/gravitational-waves-help-understand-black-hole-weight-gain

Supermassive black holes: every large galaxy’s got one. But here’s a real conundrum: how did they grow so big?

A paper in today’s issue of Science pits the front-running ideas about the growth of supermassive black holes against observational data — a limit on the strength of gravitational waves, obtained with CSIRO’s Parkes radio telescope in eastern Australia.

“This is the first time we’ve been able to use information about gravitational waves to study another aspect of the Universe — the growth of massive black holes,” co-author Dr Ramesh Bhat from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) said.

“Black holes are almost impossible to observe directly, but armed with this powerful new tool we’re in for some exciting times in astronomy. One model for how black holes grow has already been discounted, and now we’re going to start looking at the others.”

The study was jointly led by Dr Ryan Shannon, a Postdoctoral Fellow with CSIRO, and Mr Vikram Ravi, a PhD student co-supervised by the University of Melbourne and CSIRO.

Einstein predicted gravitational waves — ripples in space-time, generated by massive bodies changing speed or direction, bodies like pairs of black holes orbiting each other.

When galaxies merge, their central black holes are doomed to meet. They first waltz together then enter a desperate embrace and merge.

“When the black holes get close to meeting they emit gravitational waves at just the frequency that we should be able to detect,” Dr Bhat said.

Played out again and again across the Universe, such encounters create a background of gravitational waves, like the noise from a restless crowd.

Astronomers have been searching for gravitational waves with the Parkes radio telescope and a set of 20 small, spinning stars called pulsars.

Pulsars act as extremely precise clocks in space. The arrival time of their pulses on Earth are measured with exquisite precision, to within a tenth of a microsecond.

When the waves roll through an area of space-time, they temporarily swell or shrink the distances between objects in that region, altering the arrival time of the pulses on Earth.

The Parkes Pulsar Timing Array (PPTA), and an earlier collaboration between CSIRO and Swinburne University, together provide nearly 20 years worth of timing data. This isn’t long enough to detect gravitational waves outright, but the team say they’re now in the right ballpark.

“The PPTA results are showing us how low the background rate of gravitational waves is,” said Dr Bhat.

“The strength of the gravitational wave background depends on how often supermassive black holes spiral together and merge, how massive they are, and how far away they are. So if the background is low, that puts a limit on one or more of those factors.”

Armed with the PPTA data, the researchers tested four models of black-hole growth. They effectively ruled out black holes gaining mass only through mergers, but the other three models are still a possibility.

Dr Bhat also said the Curtin University-led Murchison Widefield Array (MWA) radio telescope will be used to support the PPTA project in the future.

“The MWA’s large view of the sky can be exploited to observe many pulsars at once, adding valuable data to the PPTA project as well as collecting interesting information on pulsars and their properties,” Dr Bhat said.

there is a short video explaining the process down bottom of the page.