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Does light generate a gravitational field?The discoveries of Rancourt and Neuman by Giovanni on 22 Aug, 2018 19:20
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An important but not very well known novelty in the world of physics is the following: it seems, from measurements made in recent experiments, that light generates a gravitational field.
https://www.researchgate.net/publication/258546838_Effect_of_light_on_gravitational_attraction
https://www.researchgate.net/publication/281189646_Further_Experiments_Demonstrating_the_Effect_of_Light_on_Gravitation
https://www.researchgate.net/publication/317773258_Experimental_verification_of_electromagnetic-gravity_effect_Weighing_light_and_heat
Applications are easy to imagine. For example, think of the following setup:
1) an unmanned spacecraft equipped with a very powerful light source.
2) a crewed ship that follows her by gravity.
The spaceship 1 could accelerate in a certain direction with a very high acceleration (say 10G) and emit light through two lasers in two opposite directions and both orthogonal to its direction of advancement.
The spaceship 2 follows the 1 due to the gravity generated by the light source mounted on 1. The power of the light source and the initial distance between the two spaceships could be set so that the spaceship 2 also undergoes an acceleration of 10G.
The peculiarity of this setup is that although the spaceship 2 has an acceleration of 10G, its crew does not feel any G: this is a feature of gravity. (a consequence of the fact that the acceleration imposed by gravity is the same on all points of the system made up of the pilots + the spaceship).
This setup requires light sources of great power (depending on the acceleration you want and the distance between spaceship 1 and 2 but let's say between 1016 and 1019 W. These numbers can be obtained by reading in the article by Neumann that 1 W of power generates the gravitational field of about 15 kg of mass). With such power it is necessary to use antimatter: in addition, exawatt lasers are not there yet.
I was therefore thinking of a different setup in which instead of a light source the spaceship 1 is equipped with a hollow container whose inner surface is perfectly reflective that is filled with light. There are many technical problems in realizing a decent approximation of this ideal setup (https://www.quora.com/Can-we-trap-light-in-box-that-is-perfectly-reflecting-from-inside) but it should be emphasized that the container must not be reusable, it must not contain light for an indefinite time: only for the time of travel.
I hope I have not made too many mistakes and I hope the articles by Roucourt, Tattersall and Neumann interest you.
Greetings.
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#1 by meberbs on 22 Aug, 2018 22:23
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From the first link:Quote
If light can block gravity, then the attraction between the 2 masses would decrease and the mobile mass would move away a little. But the opposite always happened: the mobile mass was getting closer as if the attraction was increased. Since that made no sense, the experiment was redone many times, checking if other factors were causing that movement.
"light blocking gravity" is a fairly nonsensical hypothesis.
Gravitational attraction towards the light makes sense, and when they claim it doesn't make sense, they demonstrate their lack of understanding of general relativity.
I sincerely doubt the magnitude of gravitation attraction of a mass towards light would be measurable. It is difficult to even measure gravitational attraction. The best that we even known the gravitational constant to is 46 parts per million. That means if you measured the force from a 1 kg mass, you could tell its mass to within 46 mg. 46 mg would be equivalent to 4 TJ of energy, and that is certainly not how much power they were using.
My conclusion is they these people clearly don't understand any of the physics they are talking about and most likely therefore made major flaws in their experimental design. It does not seem worth my time to figure out where their mistakes are (I'd have to check everything in detail since they have nonsense about gravitation being a "pushing" rather than "pulling" force, they probably don't even understand the expected behavior of their setup), but someone else can if they feel like it. -
#2 by Giovanni on 23 Aug, 2018 07:39
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Rancourt has his own theory on gravitation. But it's not important. The important fact here is that there are experimental evidences: light attracts matter. The experiments are not complicated or expensive. Maybe Eagleworks can try to reproduce the effect.
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#3 by meberbs on 23 Aug, 2018 08:17
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Light attracts matter is not news. It is a standard part of general relativity. It is too small of an effect to measure in a practical case, but the inverse "matter attracts light" is equivalent due to conservation of momentum. Matter bending light is much easier to detect, light of stars passing near the sun has been observed, and using gravitational lensing is a standard practice in astronomy. Also gravitational redshifts are essentially an attraction, as momentum of the light is reduced.
The measurements are not simple at all. There is a known real effect but it is much smaller than what can be detected by any current instrument. Since there is no meaningful theory presented in the paper, you would have to develop an instrument that could somehow measure things many orders of magnitude better than is currently possible. This is the same problem the emDrive has. The original thrust claims have been conclusively shown to be wrong, but since measurement accuracy is still larger than a photon rocket, and there is no good theory to provide a lower bound, people keep taking the slightest detectable signal as evidence they should keep looking.
In this case it is quite obvious that the author has absolutely no clue what they are talking about:QuoteThis gives a high sensitivity and most of the restoring force is done not by the torsion of the wires because there is almost no torsion but by the weight of the pendulum itself that tends to go to its lowest level after moving left or right.
Their description of the torsional pendulum claims it is not operating as a torsional pendulum. It would be difficult to find a more clear cut case of incompetence. Anyone spending any non-negligible time or money on this by anyone is a waste of resources that could be put to use exploring something that has a non-zero chance of success. If they are personal resources, then they are free to waste that money of course. -
#4 by Giovanni on 23 Aug, 2018 08:32
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The effect observed is far larger than the effect predicted from General Relativity. Just do the experiment: if you obtain a null result the money is not wasted....you can contact Rancourt or Neumann for dettails about their experiments.
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#5 by meberbs on 23 Aug, 2018 09:05
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The effect observed is far larger than the effect predicted from General Relativity. Just do the experiment: if you obtain a null result the money is not wasted....you can contact Rancourt or Neumann for dettails about their experiments.
Did you even read my post? It is beyond the capabilities of current technology to build an experiment that consistently would produce a null result.
Also, they describe their setup as a broken torsional pendulum. Building a broken torsional pendulum and then demonstrating that it is broken is useless.
Even if the above statements weren't true, your insistence that I do it when you haven't is disingenuous at the least. -
#6 by Giovanni on 23 Aug, 2018 09:22
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"There is a known real effect but it is much smaller than what can be detected by any current instrument. " you must not check the effect predicted by GR but the effect predicted by Rancourt.
For Eagleworks: Simply reproduce the Rancourt experiment and if the effect is not present with the magnitude Rancourt describes the question is closed. -
#7 by speedevil on 23 Aug, 2018 09:25
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"There is a known real effect but it is much smaller than what can be detected by any current instrument. " you must not check the effect predicted by GR but the effect predicted by Rancourt.
I claim that if you think really hard of unicorns, your body experiences a 1mN thrust towards galactic north.
For Eagleworks: Simply reproduce the Rancourt experiment and if the effect is not present with the magnitude Rancourt describes the question is closed.
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#8 by meberbs on 23 Aug, 2018 14:58
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you must not check the effect predicted by GR but the effect predicted by Rancourt.
I did not see any theory there making actual predictions, at least not in the first link.(And given the level of gibberish I am not inclined to read the others looking for something that probably isn't there.) The emDrive actually had force predictions made, yet we are still here long after those predictions have failed to be met many times over.For Eagleworks: Simply reproduce the Rancourt experiment and if the effect is not present with the magnitude Rancourt describes the question is closed.
Again what experiment? They straight up said that they built a broken torsional pendulum. Replicating that is pointless. Also, you are asking a U.S. government agency to waste money because some random person ran a bad experiment and misinterpreted the results. -
#9 by Giovanni on 23 Aug, 2018 15:26
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Try the experiments in the second link (i repeat the link here: https://www.researchgate.net/publication/281189646_Further_Experiments_Demonstrating_the_Effect_of_Light_on_Gravitation)
They are conceptually simpler, do not require a torsion pendulum (only a balance and some lamps) and are well described in the document linked. The result presented in "Effect of light on gravitational attraction" are published in physics essays (a peer-reviewed publication): the possibilities of errors are minimal. -
#10 by meberbs on 23 Aug, 2018 17:53
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Try the experiments in the second link (i repeat the link here: https://www.researchgate.net/publication/281189646_Further_Experiments_Demonstrating_the_Effect_of_Light_on_Gravitation)
So you are saying they moved from the standard best method for measuring tiny forces to something else. The obvious conclusion that these experiments are even less convincing, and there is further reason to doubt their competence. There is no reason to go to something else to begin with, since torsion pendulums are not that hard to build if you know what you are doing.
They are conceptually simpler, do not require a torsion pendulum (only a balance and some lamps) and are well described in the document linked. The result presented in "Effect of light on gravitational attraction" are published in physics essays (a peer-reviewed publication): the possibilities of errors are minimal.
Peer review is not some magic perfect process, and nonsense sometimes gets through. In fact, there has been research on the peer review process, and a disturbing number of publications were willing to publish auto-generated gibberish. Clearly this was not actually reviewed carefully, since the paper in the first link is so blatantly unprofessional. (They end a paragraph with "Wow...") -
#11 by Giovanni on 23 Aug, 2018 18:52
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Ok I have presented the articles, I have done my job: the implications for space exploration are clearly important.
I hope that Eagleworks will try to reproduce.
I add a little link with an interview of Louis Rancourt (dated 2012):
Thank you for the discussion. -
#12 by meberbs on 23 Aug, 2018 19:29
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Ok I have presented the articles, I have done my job: the implications for space exploration are clearly important.
There are no implications for space exploration. The only implication is that the experimenters don't know what they are doing.Thank you for the discussion.
What discussion? You are just ignoring everything that has been said here. -
#13 by whitelancer64 on 23 Aug, 2018 20:01
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This may be helpful, but I found Rancourt's website, which has descriptions and diagrams of what he has done. http://www.gravityforces.com/
In a researchgate.com comment he describes the experiment: "a gravity control panel 4 feet by 4 feet was built and using 945 watts of light giving 63000 lumen, it was discovered that over 0.1% of the weight of a 200 g mass was reduced when [the light beam was] placed under the panel or increased when placed over the panel."
So he claims there is 0.2 grams difference in a 200 g test mass if the light beam is placed below or above it. (I wonder how many data runs were necessary to figure this out
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Needless to say, this seems wildly implausible. The placement of lighting fixtures, or simply turning them on or off, in laboratories would constantly be throwing off the results of highly sensitive experiments all the time. -
#14 by Giovanni on 23 Aug, 2018 20:31
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The distance from the source is also important: I think the 'gravity control panel' is closer than lighting fixtures. It's plausible that the force decrease with the square of the distance as usual for gravity so the effect of lighting fixtures would be irrelevant. Furthermore the power of lighting fixtures should be in 25-400 W range.
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#15 by whitelancer64 on 23 Aug, 2018 23:09
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The distance from the source is also important: I think the 'gravity control panel' is closer than lighting fixtures. It's plausible that the force decrease with the square of the distance as usual for gravity so the effect of lighting fixtures would be irrelevant. Furthermore the power of lighting fixtures should be in 25-400 W range.
There are commercially available 1000 watt lights that are quite cheap. They are commonly used as grow lamps.
Even considering the inverse square law, for very highly sensitive measurements they would have a noticeable effect.
It would have been a plague upon high precision science for decades now. -
#16 by Giovanni on 24 Aug, 2018 05:55
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Stronger dependencies from distance are also possibles. They should be experimentally investigated. The problem is that if we do not try the first time we will never know.
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#17 by ChrisWilson68 on 24 Aug, 2018 08:33
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Stronger dependencies from distance are also possibles. They should be experimentally investigated. The problem is that if we do not try the first time we will never know.
If that were true, it would have caused all sorts of effects in many, many different kinds of experiments. Scientists couldn't have helped but noticed, because there would have been unexplained signals in their data.
That's what whitelancer64 already told you.
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#18 by Giovanni on 24 Aug, 2018 08:53
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With " stronger dependecies " I mean a force that goes as r-4 or e-r. In those cases the effect could easily go unnoticed.
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#19 by francesco nicoli on 24 Aug, 2018 09:39
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The distance from the source is also important: I think the 'gravity control panel' is closer than lighting fixtures. It's plausible that the force decrease with the square of the distance as usual for gravity so the effect of lighting fixtures would be irrelevant. Furthermore the power of lighting fixtures should be in 25-400 W range.
There are commercially available 1000 watt lights that are quite cheap. They are commonly used as grow lamps.
Even considering the inverse square law, for very highly sensitive measurements they would have a noticeable effect.
It would have been a plague upon high precision science for decades now.
that must be why I feel so pushed to work under the horrible enormous lamps of my office...
)