If you were to be inside say, an elevator, what you feel whilst standing inside the box for your body weight would be indistinguishable from whether the elevator was static at the surface of the earth, or whether it was onboard a spaceship in deep space accelerating at 9.8m/s2.
Or some combination of the two .... not afar, but also not too near Earth and also accelerating. Whatever gravity/inertial summation gives 9.8 m/s^2 ....
This was Einstein's brilliant insight. You will find some airframe/component limits quoted as say -2g to +6g, with an implicit 'here on planet Earth' assumption. So you add 1g to get the range as experienced within : -1g to +7g. See the Vomit Comet, where you can be in 'free fall' even as you go on the upwards leg of the parabola.
[ it's a historical point that humans have generally/mostly experienced the downgoing arcs of parabolae ]
It's harder to grasp, but I prefer to say 'affected only by the force of gravity' in place of 'free fall'.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
A Planck length long by a Planck length wide get's you a Planck area. As thick as two short Planck's .... :-)
Very good... :-)
Quote:
With or without a factor of PI, 2 or 4 or even G ( depending on who you ask ) gives you a bit's worth of information/entropy.
But, as Martin says, this is an abstraction. The idea of reconstructing the state of the interior of a volume from it's bounding surface is a derivation. It's a bit like a magic square, or the inversion of a matrix as per computerised tomography. It's sounds like a cheat in that one can 'compress' volume information to an area
I guess if you were happy to 'compress' your holographic data so that you have a non-uniform representation of the volume, you could super-resolve some parts of the volume to detail that is much finer than two short plancks... :-p
For example, have an undulating bounding surface such that some parts of the volume are super-resolved at the expense of other parts being more "fuzzy".
Quote:
but it is important to understand that you have to have an algorithm to do that. So :
Volume information = Area information + algorithm
thus you've 'hidden' information in the presence/complexity/need for an algorithm. As programmers know one can often trade executable size for data file size ( thus speed for memory generally ). Take zip/unzip technology for instance ....
I think an impressive example is the demoscene of the 1990's. There were some phenomenal results from just 64k bytes (524288 bits or less) of code and data running on a DOS PC. One that stunned me at the time is:
Note the list of statistics at the end. All within the 16bit address space of an 8bit microcomputer. Or for comparison, all within just a few seconds of mp3 music, or less than a second of DVD video!
Note: That is a long time before today's fancy graphics cards!
We also have the example of DNA, except there the 'algorithm' isn't compltely deterministic as it is with the demoscene code. For example, how identical are 'identical' twins physically and mentally?
Quote:
( edit ) And when Mr Kaku wants to represent a Theory Of Everything by an equation 'a few inches long', he is hiding a huge interpretative machinery to unwrap the content for a given application...
Or an entire universe of physics to play out the results for a real world result. If you want a different result, then you need a different universe to play out your different rules for the interpretation.
Another example is the Mandelbrot set. You can get infinitely varied but completely repeatable and consistent imagery by tweaking how you visualise the iterative function that is the Mandelbrot set. And then there are also the Julia set and others...
Bit twiddling aside. Has information theory and information entropy been able to make any useful predictions cosmologically? The only example I can think of is the twist for the information loss for black holes that suggests the existance of Hawking radiation that then lets them evaporate away...
If you were to be inside say, an elevator, what you feel whilst standing inside the box for your body weight would be indistinguishable from whether the elevator was static at the surface of the earth, or whether it was onboard a spaceship in deep space accelerating at 9.8m/s2.
Or some combination of the two .... not afar, but also not too near Earth and also accelerating. Whatever gravity/inertial summation gives 9.8 m/s^2 ....
This was Einstein's brilliant insight. ...
It's harder to grasp, but I prefer to say 'affected only by the force of gravity' in place of 'free fall'.
I still consider it fascinating how 'gravity' appears to in effect be (is indistinguishable from) acceleration.
We may yet be trying to research an ethereal pseudo force...
Hopefully, the LHC will throw up a few clues.
Another aspect is that each leap of understanding in physics has required another assumed "absolute" to be reappraised as "relative"... It is all very much a case of viewpoint!
I guess if you were happy to 'compress' your holographic data so that you have a non-uniform representation of the volume, you could super-resolve some parts of the volume to detail that is much finer than two short plancks... :-p
For example, have an undulating bounding surface such that some parts of the volume are super-resolved at the expense of other parts being more "fuzzy".
My understanding is that the bounding area information, which will change with time ( or successive slices of a spacetime 'tunnel' ), plus the algorithm to unwrap yields all the interactions between the particles within. Personally I view this as a compression technique based on the regularities/rules rather than anything fundamental. Accounting after the fact. But being within the object of discussion, I would say that wouldn't I ??? :-)
Quote:
I think an impressive example is the demoscene of the 1990's .......... fancy graphics cards!
Very impressive indeed, effectively good examples of (pre)compilation vs. interpretation too.
Quote:
We also have the example of DNA, except there the 'algorithm' isn't compltely deterministic as it is with the demoscene code. For example, how identical are 'identical' twins physically and mentally?
Their identity diverges from the moment the fertilised ovum splits.
A self altering algorithm, in that gene action is only 'sensible' in the presence of a milieu of genes. I think the error rate of DNA polymerases ( the 'DNA photocopiers' ) is about one per billion bases. Not enough to worry everyday use, but enough to act on longer timescales to introduce variation - not the only mechanism of variation though.
Quote:
Another example is the Mandelbrot set. You can get infinitely varied but completely repeatable and consistent imagery by tweaking how you visualise the iterative function that is the Mandelbrot set. And then there are also the Julia set and others...
An good example. Interestingly because of the iterative nature of the calculation the precision and rounding errors become part of the repeatability.
Quote:
Bit twiddling aside. Has information theory and information entropy been able to make any useful predictions cosmologically? The only example I can think of is the twist for the information loss for black holes that suggests the existance of Hawking radiation that then lets them evaporate away...
One can deduce Hawking radiation without thermodynamics. Apply QED to nearby the horizon. GR is a classic theory so the horizon becomes a fuzzy layer rather than an exact infinitely thin surface. Quantum ideas allow the creation of particle/antiparticle pairs ( Heisenberg uncertainty permitting large enough energy fluctuations over sufficiently short time intervals ), and then probabilistic capture ( extension of the wave wave function to well enough within the horizon radius ) of one of the pair. The other escapes to distance and thus removing mass/energy from the deal. The entropy aspect was related later on by the work of Susskind and others.
Quote:
I still consider it fascinating how 'gravity' appears to in effect be (is indistinguishable from) acceleration.
We may yet be trying to research an ethereal pseudo force...
Hopefully, the LHC will throw up a few clues.
Well, we deal with 'effective' theories. Meaning that they apply within denoted scales. Newton still works great for bridges etc. GPS is the only everyday thing I can think of that really needs GR, say [ will wander by 10+ km's per day if no GR time corrections are applied ].
Quote:
Another aspect is that each leap of understanding in physics has required another assumed "absolute" to be reappraised as "relative"... It is all very much a case of viewpoint!
Curiously Einstein wanted to call SR 'invariant theory' but was talked out of it. He wanted to emphasise what remained constant between reference frames ( speed of light, spacetime intervals ... ). As for GR I guess the one real constant is the mass proportionality of gravity/inertia. If you have a force or effect which depends only on that then GR is applicable ( as opposed to electric charge, quantum spin number or whatever ). Sharp punters will note the neat circularity here as mass is measured/benchmarked upon inertial or gravitational grounds anyway. But it is self consistent none-the-less and leads to a workable framework.
Cheers, Mike.
( edit )
Quote:
..... without thermodynamics.
Well, you have to have conservation of energy. :-)
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
I still consider it fascinating how 'gravity' appears to in effect be (is indistinguishable from) acceleration.
Try this for another aspect - 'little' versions of The Twin's Paradox are happening all the time :
I get up from a chair and walk out of the room, later returning to sit back down with you who stayed put.
Two sailors in a catamaran turning around a marker bouy. One is at the tiller, the other leaning back out over the gunnel.
I go for a drive in the countryside, up hill and down dale, visit this town, take in the view from that peak, wind along a valley. You stayed home watching the cricket on the TV.
The bowler walks back to his crease, runs a up and delivers the ball, and then waits while the batsmen run between the wickets.
.... right up to Neil and Buzz ( and Michael. Everyone forgets Michael !! ), who spend a week away from the planet. After splashdown they get checked out by the very doctor that OK'ed them for launch.
Everybody, everyday, are undergoing different acceleration histories. Utterly trivial in effect with the speed of light being the magnitude that it is compared to us. Imagine if c was much less, or if our a's and v's were much more ....
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
I still consider it fascinating how 'gravity' appears to in effect be (is indistinguishable from) acceleration.
Try this for another aspect - 'little' versions of The Twin's Paradox are happening all the time :
[...]
I go for a drive in the countryside, up hill and down dale, ...
Everybody, everyday, are undergoing different acceleration histories. Utterly trivial in effect with the speed of light being the magnitude that it is compared to us. Imagine if c was much less, or if our a's and v's were much more ....
Indeed so, even if you are splitting very small fractions of seconds.
However, for what relativity longevity you might gain from lots of driving, I'm sure you'll age biologically many times faster than that due to the stress of the driving and from the unhealthy fumes whilst trapped in the metal box!
One theory of gravity is that gravitational force is mediated by 'particles' called 'gravitons'. Indeed, one of the aims of the LHC is to search for the Higgs boson that is implicated with such stuff...
So...
If the graviton has energy, how does the source itself not lose energy in emitting such particles?
The graviton must be very weakly interacting with matter so as not to be shielded by matter, yet how would any 'force' be transferred by such an infinitesimally rare or weak an interaction with a target?
Indeed so, even if you are splitting very small fractions of seconds.
However, for what relativity longevity you might gain from lots of driving, I'm sure you'll age biologically many times faster than that due to the stress of the driving and from the unhealthy fumes whilst trapped in the metal box!
Absolutely! In any case your subjective experience as a driver is not special, in that when you return home everyone else will be a bit older than what you would have expected otherwise. The time effect is beyond clocks, so compared to the stay-at-homers you heart is beating fewer times, the electrical impulses in your brain are slower etc .... you won't feel any slow-motion going on.
Here's a thought : try The Triplet's Paradox ( my invention ). Have one stay on planet Earth ( call him/her Static ) but the other two go to Alpha Centauri and back [ leaving simultaneously ].
However one ( Slowpoke ) travels at one-tenth light speed, 'instantly' accelerating to that speed from the get-go, flipping the rocket over at Alpha Centauri and 'immediately' return back at the same speed.
The third triplet ( Zippy ) also goes there and back to Alpha Centauri in a identical fashion to Slowpoke but at nine-tenths of light speed.
Assuming light always takes 8 years to do the same round trip to Alpha Centauri for the duration of this escapade, then :
- who does Static see first come back ( Slowpoke or Zippy ), when in Static's timeline, and what's the age difference?
- ditto for the remaining triplet.
Ignore Earth and Alpha Centauri in the gravitational sense, or anything else, as they are just markers for journey endpoints.
I'll post the answer later ..... :-)
Quote:
One theory of gravity is that gravitational force is mediated by 'particles' called 'gravitons'. Indeed, one of the aims of the LHC is to search for the Higgs boson that is implicated with such stuff...
So...
If the graviton has energy, how does the source itself not lose energy in emitting such particles?
The graviton must be very weakly interacting with matter so as not to be shielded by matter, yet how would any 'force' be transferred by such an infinitesimally rare or weak an interaction with a target?
It's a modelling thing. There are no such things as waves. There are no such things as particles. What we have are real world phenomena or 'things' which we choose to describe by wave or particle models or a blend like QED. The 'graviton' is a way of saying that gravity comes in bunches similiar to the way light comes in photons.
But if a photon crosses past another photon then ( ignoring particle creation if the energies are high ) they will not affect each other. Any effect on the rest of the universe will be a linear superposition of the two, including phase as well as magnitudes.
Not so for gravitons, as presently modelled at least. In essence two nearby gravitons do affect each other and the effect for the rest of us is not linear.
With QED the denominator in the probability calculation for some event can be readily 'normalised' ( or 'renormalised' actually ). It's a way of ensuring that all probabilities must add up to one - that is something must happen, where something includes the scenario that nothing changed. The attempts to quantise gravity, meaning you make lumps called gravitons, gives incalculable/infinite denominators. That's like saying what is the probability of a double six on a dice throw but you don't know the full range of possible dice face combinations. The failure to form the denominator is linked to the non-linearity.
So why is gravity non-linear? Essentially because the Einstein GR equations are non-linear. They have linearised forms for sure, but using approximations ( low field strengths typically ). So I can have something along the X-direction which affects the Y-direction metric component ( a 'length' ) that then asserts itself upon the Z-direction metric which then ...... you get the idea. To solve all ten ( the independent subgroup out of a set of sixteen ) equations is very, very hard.
Quote:
Or is this indeed all a game of pseudo forces?
In ( most modern ) planes there is the 'balance ball'. Take a short glass tube bent into an even curve - a small part of a circular arc. Fill it with a mildly viscous fluid and a dense ball of slightly smaller diameter than the inner diameter of the glass tube. Carefully insert into the cockpit such that when stationary and sitting 'square' on the ground the ball sits in the middle of the tube - at the lowest point. It has an equal amount of tube either side of the ball, both 'uphill' because of the curve :
This is reminiscent of the air bubble in the builder's level. If the ball is midway b/w the markers you have a 'balanced' turn or co-ordinated manouevre. It is telling you which direction is 'down' in the inertial sense. Passengers in the craft will feel the g's in a direction exactly towards the floor, albeit possibly greater than the usual 1 g.
Now if we make a turn to the left, but our ailerons/rudder is not such that balance occurs, with the ball situated to the left of the neutral mark then passengers will feel a 'lean' towards the left bulkhead. They sense that the plane is moving away from them toward the right. This is denoted as a 'slip' or slipping into the turn.
If the ball is to the right side in a left turn then passengers feel a lean to the right bulkhead and thus sense the plane moving towards their left. This is called a 'skid', much like you would feel in a skidding car. Indeed when taxiing and turning on the ground you will see the ball go to the outer side of the turn in this fashion.
[ But I've seen disagreement upon what subjective sensation ought be applied to the either word skid or slip. ]
The terrific beauty of this gadget is that, provided it is intact and not inverted, it will always work. No electricity, nor vacuum/suction, is required. Strictly speaking it is a little bit of general relativity in the cockpit. It tells you what the local summation of gravity and inertia is.
[ The usual correction for out-of-balance is to apply rudder to the side of the ball's displacement - 'step on the ball' - although it is really the aileron/rudder combination doing stuff. There is a yaw/roll link with use of either of those controls. Generally the elevator is determining the angle of attack, and together with aileron the turn rate. So the rudder is the remaining control degree to use to achieve balance ... even though you don't have to be in balance, it's certainly more comfortable. ]
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
- who does Static see first come back ( Slowpoke or Zippy )
Cheers, Mike.
I would say neither would come back as, if they accelerated to that speed instantly … they would both be DEAD !
If they have some clever 'warp drive' that merely lets them ride the spacetime curvature down to a lower level ("deeper into a gravity well") to then zip along at whatever speed to then ride up the spacetime curvature at their destination, they won't feel a thing!
Ooops... That sounds just like riding on anti-gravity from star to star!!
Quote:
Then again ….. maybe Rod Serling will appear here any minute at my home and, explain it all to me :-)
OK... Who's he?
Something to do with engines and heat conversion?
Cheers,
Martin
(I'll need another brew or few before commenting on the prior posting... :-o Later...)
RE: If you were to be
)
Or some combination of the two .... not afar, but also not too near Earth and also accelerating. Whatever gravity/inertial summation gives 9.8 m/s^2 ....
This was Einstein's brilliant insight. You will find some airframe/component limits quoted as say -2g to +6g, with an implicit 'here on planet Earth' assumption. So you add 1g to get the range as experienced within : -1g to +7g. See the Vomit Comet, where you can be in 'free fall' even as you go on the upwards leg of the parabola.
[ it's a historical point that humans have generally/mostly experienced the downgoing arcs of parabolae ]
It's harder to grasp, but I prefer to say 'affected only by the force of gravity' in place of 'free fall'.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: A Planck length long by
)
Very good... :-)
I guess if you were happy to 'compress' your holographic data so that you have a non-uniform representation of the volume, you could super-resolve some parts of the volume to detail that is much finer than two short plancks... :-p
For example, have an undulating bounding surface such that some parts of the volume are super-resolved at the expense of other parts being more "fuzzy".
I think an impressive example is the demoscene of the 1990's. There were some phenomenal results from just 64k bytes (524288 bits or less) of code and data running on a DOS PC. One that stunned me at the time is:
Farbrausch - fr-08: .the .product
Note the list of statistics at the end. All within the 16bit address space of an 8bit microcomputer. Or for comparison, all within just a few seconds of mp3 music, or less than a second of DVD video!
Further examples for those interested:
Fairlight - Come Clean
Fairlight - Dead Ringer
the wonderful world of 64k intros.
Note: That is a long time before today's fancy graphics cards!
We also have the example of DNA, except there the 'algorithm' isn't compltely deterministic as it is with the demoscene code. For example, how identical are 'identical' twins physically and mentally?
Or an entire universe of physics to play out the results for a real world result. If you want a different result, then you need a different universe to play out your different rules for the interpretation.
Another example is the Mandelbrot set. You can get infinitely varied but completely repeatable and consistent imagery by tweaking how you visualise the iterative function that is the Mandelbrot set. And then there are also the Julia set and others...
Bit twiddling aside. Has information theory and information entropy been able to make any useful predictions cosmologically? The only example I can think of is the twist for the information loss for black holes that suggests the existance of Hawking radiation that then lets them evaporate away...
?
Regards,
Martin
See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)
RE: RE: If you were to be
)
I still consider it fascinating how 'gravity' appears to in effect be (is indistinguishable from) acceleration.
We may yet be trying to research an ethereal pseudo force...
Hopefully, the LHC will throw up a few clues.
Another aspect is that each leap of understanding in physics has required another assumed "absolute" to be reappraised as "relative"... It is all very much a case of viewpoint!
Regards,
Martin
See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)
RE: I guess if you were
)
My understanding is that the bounding area information, which will change with time ( or successive slices of a spacetime 'tunnel' ), plus the algorithm to unwrap yields all the interactions between the particles within. Personally I view this as a compression technique based on the regularities/rules rather than anything fundamental. Accounting after the fact. But being within the object of discussion, I would say that wouldn't I ??? :-)
Very impressive indeed, effectively good examples of (pre)compilation vs. interpretation too.
Their identity diverges from the moment the fertilised ovum splits.
A self altering algorithm, in that gene action is only 'sensible' in the presence of a milieu of genes. I think the error rate of DNA polymerases ( the 'DNA photocopiers' ) is about one per billion bases. Not enough to worry everyday use, but enough to act on longer timescales to introduce variation - not the only mechanism of variation though.
An good example. Interestingly because of the iterative nature of the calculation the precision and rounding errors become part of the repeatability.
One can deduce Hawking radiation without thermodynamics. Apply QED to nearby the horizon. GR is a classic theory so the horizon becomes a fuzzy layer rather than an exact infinitely thin surface. Quantum ideas allow the creation of particle/antiparticle pairs ( Heisenberg uncertainty permitting large enough energy fluctuations over sufficiently short time intervals ), and then probabilistic capture ( extension of the wave wave function to well enough within the horizon radius ) of one of the pair. The other escapes to distance and thus removing mass/energy from the deal. The entropy aspect was related later on by the work of Susskind and others.
Well, we deal with 'effective' theories. Meaning that they apply within denoted scales. Newton still works great for bridges etc. GPS is the only everyday thing I can think of that really needs GR, say [ will wander by 10+ km's per day if no GR time corrections are applied ].
Curiously Einstein wanted to call SR 'invariant theory' but was talked out of it. He wanted to emphasise what remained constant between reference frames ( speed of light, spacetime intervals ... ). As for GR I guess the one real constant is the mass proportionality of gravity/inertia. If you have a force or effect which depends only on that then GR is applicable ( as opposed to electric charge, quantum spin number or whatever ). Sharp punters will note the neat circularity here as mass is measured/benchmarked upon inertial or gravitational grounds anyway. But it is self consistent none-the-less and leads to a workable framework.
Cheers, Mike.
( edit )
Well, you have to have conservation of energy. :-)
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: I still consider it
)
Try this for another aspect - 'little' versions of The Twin's Paradox are happening all the time :
I get up from a chair and walk out of the room, later returning to sit back down with you who stayed put.
Two sailors in a catamaran turning around a marker bouy. One is at the tiller, the other leaning back out over the gunnel.
I go for a drive in the countryside, up hill and down dale, visit this town, take in the view from that peak, wind along a valley. You stayed home watching the cricket on the TV.
The bowler walks back to his crease, runs a up and delivers the ball, and then waits while the batsmen run between the wickets.
.... right up to Neil and Buzz ( and Michael. Everyone forgets Michael !! ), who spend a week away from the planet. After splashdown they get checked out by the very doctor that OK'ed them for launch.
Everybody, everyday, are undergoing different acceleration histories. Utterly trivial in effect with the speed of light being the magnitude that it is compared to us. Imagine if c was much less, or if our a's and v's were much more ....
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: RE: I still consider
)
Indeed so, even if you are splitting very small fractions of seconds.
However, for what relativity longevity you might gain from lots of driving, I'm sure you'll age biologically many times faster than that due to the stress of the driving and from the unhealthy fumes whilst trapped in the metal box!
Cheers,
Martin
See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)
One theory of gravity is that
)
One theory of gravity is that gravitational force is mediated by 'particles' called 'gravitons'. Indeed, one of the aims of the LHC is to search for the Higgs boson that is implicated with such stuff...
So...
If the graviton has energy, how does the source itself not lose energy in emitting such particles?
The graviton must be very weakly interacting with matter so as not to be shielded by matter, yet how would any 'force' be transferred by such an infinitesimally rare or weak an interaction with a target?
Or is this indeed all a game of pseudo forces?
Cheers,
Martin
See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)
RE: Indeed so, even if you
)
Absolutely! In any case your subjective experience as a driver is not special, in that when you return home everyone else will be a bit older than what you would have expected otherwise. The time effect is beyond clocks, so compared to the stay-at-homers you heart is beating fewer times, the electrical impulses in your brain are slower etc .... you won't feel any slow-motion going on.
Here's a thought : try The Triplet's Paradox ( my invention ). Have one stay on planet Earth ( call him/her Static ) but the other two go to Alpha Centauri and back [ leaving simultaneously ].
However one ( Slowpoke ) travels at one-tenth light speed, 'instantly' accelerating to that speed from the get-go, flipping the rocket over at Alpha Centauri and 'immediately' return back at the same speed.
The third triplet ( Zippy ) also goes there and back to Alpha Centauri in a identical fashion to Slowpoke but at nine-tenths of light speed.
Assuming light always takes 8 years to do the same round trip to Alpha Centauri for the duration of this escapade, then :
- who does Static see first come back ( Slowpoke or Zippy ), when in Static's timeline, and what's the age difference?
- ditto for the remaining triplet.
Ignore Earth and Alpha Centauri in the gravitational sense, or anything else, as they are just markers for journey endpoints.
I'll post the answer later ..... :-)
It's a modelling thing. There are no such things as waves. There are no such things as particles. What we have are real world phenomena or 'things' which we choose to describe by wave or particle models or a blend like QED. The 'graviton' is a way of saying that gravity comes in bunches similiar to the way light comes in photons.
But if a photon crosses past another photon then ( ignoring particle creation if the energies are high ) they will not affect each other. Any effect on the rest of the universe will be a linear superposition of the two, including phase as well as magnitudes.
Not so for gravitons, as presently modelled at least. In essence two nearby gravitons do affect each other and the effect for the rest of us is not linear.
With QED the denominator in the probability calculation for some event can be readily 'normalised' ( or 'renormalised' actually ). It's a way of ensuring that all probabilities must add up to one - that is something must happen, where something includes the scenario that nothing changed. The attempts to quantise gravity, meaning you make lumps called gravitons, gives incalculable/infinite denominators. That's like saying what is the probability of a double six on a dice throw but you don't know the full range of possible dice face combinations. The failure to form the denominator is linked to the non-linearity.
So why is gravity non-linear? Essentially because the Einstein GR equations are non-linear. They have linearised forms for sure, but using approximations ( low field strengths typically ). So I can have something along the X-direction which affects the Y-direction metric component ( a 'length' ) that then asserts itself upon the Z-direction metric which then ...... you get the idea. To solve all ten ( the independent subgroup out of a set of sixteen ) equations is very, very hard.
In ( most modern ) planes there is the 'balance ball'. Take a short glass tube bent into an even curve - a small part of a circular arc. Fill it with a mildly viscous fluid and a dense ball of slightly smaller diameter than the inner diameter of the glass tube. Carefully insert into the cockpit such that when stationary and sitting 'square' on the ground the ball sits in the middle of the tube - at the lowest point. It has an equal amount of tube either side of the ball, both 'uphill' because of the curve :
This is reminiscent of the air bubble in the builder's level. If the ball is midway b/w the markers you have a 'balanced' turn or co-ordinated manouevre. It is telling you which direction is 'down' in the inertial sense. Passengers in the craft will feel the g's in a direction exactly towards the floor, albeit possibly greater than the usual 1 g.
Now if we make a turn to the left, but our ailerons/rudder is not such that balance occurs, with the ball situated to the left of the neutral mark then passengers will feel a 'lean' towards the left bulkhead. They sense that the plane is moving away from them toward the right. This is denoted as a 'slip' or slipping into the turn.
If the ball is to the right side in a left turn then passengers feel a lean to the right bulkhead and thus sense the plane moving towards their left. This is called a 'skid', much like you would feel in a skidding car. Indeed when taxiing and turning on the ground you will see the ball go to the outer side of the turn in this fashion.
[ But I've seen disagreement upon what subjective sensation ought be applied to the either word skid or slip. ]
The terrific beauty of this gadget is that, provided it is intact and not inverted, it will always work. No electricity, nor vacuum/suction, is required. Strictly speaking it is a little bit of general relativity in the cockpit. It tells you what the local summation of gravity and inertia is.
[ The usual correction for out-of-balance is to apply rudder to the side of the ball's displacement - 'step on the ball' - although it is really the aileron/rudder combination doing stuff. There is a yaw/roll link with use of either of those controls. Generally the elevator is determining the angle of attack, and together with aileron the turn rate. So the rudder is the remaining control degree to use to achieve balance ... even though you don't have to be in balance, it's certainly more comfortable. ]
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: - who does Static see
)
I would say neither would come back as, if they accelerated to that speed instantly … they would both be DEAD !
Then again ….. maybe Rod Serling will appear here any minute at my home and, explain it all to me :-)
Bill
RE: RE: - who does
)
If they have some clever 'warp drive' that merely lets them ride the spacetime curvature down to a lower level ("deeper into a gravity well") to then zip along at whatever speed to then ride up the spacetime curvature at their destination, they won't feel a thing!
Ooops... That sounds just like riding on anti-gravity from star to star!!
OK... Who's he?
Something to do with engines and heat conversion?
Cheers,
Martin
(I'll need another brew or few before commenting on the prior posting... :-o Later...)
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