Is gravity an infinite source of energy?

[Xtensity]

I was thinking about Hydroelectric generator turbines which are built underwater to utilize the energy of the waves/current.

I was thinking that if the waves are generated by the moons gravitational pull... would the presence of the moon cause the waves to continually being made, resulting in a seemingly infinite source of energy?

Perhaps this is the wrong section of the forum, but is gravity an infinite force since it is created by the presence of Mass? Whether it's gravitons doing it or simply bends in the Space-Time Continuum.


Ideas?

 

[Borek]

No, gravity is not an infinite source of energy.

TANSTAAFL

Using tidal waves for electricity generation slows down the Earth rotation.

 

[Xtensity]

You did not address the question though.

I have discussed the idea of robbing the Earth's kinetic energy as a source of energy many times, and yes it would slow the Earth's rotation.

I said nothing about tidal waves because they're utilizing energy from tectonic plate movement, which if we used that for electrical energy the Earth's rotation would slow. I am talking about normal waves. Waves not generated by tectonic plate movement.

Waves generated as a direct result from wind AND the gravitation pull of the moon.

Does some of the energy in waves not come from the moons gravitational pull? If not then why do waves get larger and more powerful(aka more energy in them) during full moons or at night.

Meaning if gravity can increase the energy of the tides, then why can the gravitational energy of the moon not be utilized to generate some kind of energy?

I actually am thinking you didn't even read the thread because based upon your response, it seems you formed your response after seeing the words "infinite", "Gravity", and "wave".

Can you explain why gravity is not infinite.

If gravity is a force, and energy is not infinite, would an object loose its gravitational pull over time despite still having the mass which originally produced the gravity?

Whether that gravity is caused by gravitons being created by the presence of mass, or simply bends in Space-Time forcing objects to roll towards massive enough objects.

 

[n.karthick]

Using tidal waves for electricity generation slows down the Earth rotation.

If the above statement is true, then if I jump up and down it would disturb Earth's rotation.

 

[Xtensity]

If the above statement is true, then if I jump up and down it would disturb Earth's rotation.

Yes, but by a negligible amount.

When the tidal waves hit a Turbine, the turbines kinetic energy is turned into electrical energy which is stored...

If the turbine is never hit then the energy simply goes back into the earth/ocean as it smashes down.

Though I do not know of any turbine that can withstand a tidal wave and even if we somehow did absorb all of the energy from a tidal wave, the Earth's rotation would not slow by any noticeable amount unless we did this for a very long time with every tidal wave that occurs. The same goes with leeching off the Earth's rotational energy, it slows it down, but it may take quite a bit of down for a noticeable difference.

 

[Borek]

If the turbine is never hit then the energy simply goes back into the earth/ocean as it smashes down.

Not exactly - part of the energy is dispersed as a heat, so the slowing takes place whether we harvest the energy or not. See below.

Though I do not know of any turbine that can withstand a tidal wave

The idea is to find a narrow bay, then to close it with a dam, so that tidal wave can be trapped. Then you use normal turbines.

and even if we somehow did absorb all of the energy from a tidal wave, the Earth's rotation would not slow by any noticeable amount unless we did this for a very long time with every tidal wave that occurs. The same goes with leeching off the Earth's rotational energy, it slows it down, but it may take quite a bit of down for a noticeable difference.

Process is slow, but observable, especially in long periods of time. Paleontological evidence suggests Devonian year was around 400 days, which means Earth was rotating substantially faster.

 

[Xtensity]

Not exactly - part of the energy is dispersed as a heat, so the slowing takes place whether we harvest the energy or not. See below.



The idea is to find a narrow bay, then to close it with a dam, so that tidal wave can be trapped. Then you use normal turbines.



Process is slow, but observable, especially in long periods of time. Paleontological evidence suggests Devonian year was around 400 days, which means Earth was rotating substantially faster.

All of that is true, I wasn't thinking about the heat aspect.

Though you still never addressed what I asked about gravitation effects on the waves, and if gravity will ever actually run out assuming the object producing the gravity remains.

 

[sophiecentaur]

All of that is true, I wasn't thinking about the heat aspect.

Though you still never addressed what I asked about gravitation effects on the waves, and if gravity will ever actually run out assuming the object producing the gravity remains.

You state the question in a strange way. "Gravity" is a form of Potential Energy. The energy is 'there' because of the separation of two objects. As they get closer together, the potential gets lower and lower. It's only gone when they are resting right next to each other.
There is another factor, of course, and that is that Orbital Energy consists of a combination of Kinetic and Potential energy. Only in cases like Hydro Power, on the surface of the Earth, are we just talking in terms of stored Potential Energy. Mostly, we are dealing with KE and PE.

 

[Xtensity]

You state the question in a strange way. "Gravity" is a form of Potential Energy. The energy is 'there' because of the separation of two objects. As they get closer together, the potential gets lower and lower. It's only gone when they are resting right next to each other.
There is another factor, of course, and that is that Orbital Energy consists of a combination of Kinetic and Potential energy. Only in cases like Hydro Power, on the surface of the Earth, are we just talking in terms of stored Potential Energy. Mostly, we are dealing with KE and PE.

How can energy/pull be "Gone" if they are resting right next to each other? When they are resting right next to each other, there is still an attraction between the 2 objects.

As far as I am aware, gravity has been theorized as bends in Space-Time, which results in objects rolling along the fabric of space-time via the Curvature of the bend which the massive object created.
[URL]http://akorra.com/blog/wp-content/uploads/2009/02/theory-of-gravity.jpg[/URL]

Then there's the theoretical particle gravitons which are massless and generated by the simple presence of mass. They travel at infinite speed due to having no mass so their location can not be measured. An object simply existing it is producing "Gravitons" in all direction at infinite speed. Gravitons pass through all matter and because of their spin they create the force which seemingly pulls objects in whichever direction the graviton came from.

Whichever of these theories of gravity are true, neither of them contradict because they both have the same properties. Instantaneous effect in all directions. Regardless of all this... Can you explain why tides and waves are strengthened during heightened lunar activity(at night, etc). If the waves are becoming larger, then this must mean more energy is entering the wave from somewhere... which it has been said is the graviational pull.

What mistake in my thinking am I making, since based on what I observe to be the moons gravitational effects on the waves, this is what is happening. (sorry if this last sentence is foggy, I am having a hard time putting that into words)

 

[n.karthick]

Then there's the theoretical particle gravitons which are massless and generated by the simple presence of mass. They travel at infinite speed due to having no mass so their location can not be measured. An object simply existing it is producing "Gravitons" in all direction at infinite speed. Gravitons pass through all matter and because of their spin they create the force which seemingly pulls objects in whichever direction the graviton came from.

Whichever of these theories of gravity are true, neither of them contradict because they both have the same properties. Instantaneous effect in all directions.

As far as I know from physics, nothing can travel faster than light. Infinite speed for anything is not possible at all. Even effect of gravity can travel at light speed only. That is what Einstein theory of relativity says. If sun disappears suddenly we cannot know it (including its gravitational effect) for 8 minutes (approx). I am confused with your saying that gravitons travel at infinite speed, their instantaneous effect .

 

[Borek]

Whichever of these theories of gravity are true, neither of them contradict because they both have the same properties. Instantaneous effect in all directions.

Gravity is not instantaneous, it travels at c.

 

[russ_watters]

Though you still never addressed what I asked about gravitation effects on the waves, and if gravity will ever actually run out assuming the object producing the gravity remains.

Actually, he did, but you're confusing two separate issues here, which is why you aren't seeing it. "Gravity" is not an energy source, it is a field or a static force. So it is meaningless to ask if it will "run out". A book sitting on a table will always have about the same force pulling it to the table and that force will never "run out", but there is no energy usage associated with it.

Tidal power plants don't steal "gravity" energy, they steal rotational kinetic energy. A changing gravitational field is just how the rotational energy is transported. This energy source will "run out" when the Earth and moon become tidally locked.

Similarly, a hydroelectric dam is ultimately powered by the sun. Gravity's involvement is just in transporting the water up and down. This is also similar to a typical steam engine, where a pump transports the steam, but the boiler is what supplies the energy to run the turbine.

Regardless of all this... Can you explain why tides and waves are strengthened during heightened lunar activity(at night, etc). If the waves are becoming larger, then this must mean more energy is entering the wave from somewhere... which it has been said is the graviational pull.

Well the moon can be in the sky at any time, not just at night, but this is also a peculiar question. The phrase "lunar activity" has no meaning that I can discern.

Tides are on a daily cycle (with two peaks) that changes very little from day to day. The tides get stronger when heavenly bodies align and when the distance changes by a significant amount. Both of these occur on nearly monthly cycles (again, with two peaks).

 

[Xtensity]

Actually, he did, but you're confusing two separate issues here, which is why you aren't seeing it. "Gravity" is not an energy source, it is a field or a static force. So it is meaningless to ask if it will "run out". A book sitting on a table will always have about the same force pulling it to the table and that force will never "run out", but there is no energy usage associated with it.

Tidal power plants don't steal "gravity" energy, they steal rotational kinetic energy. A changing gravitational field is just how the rotational energy is transported. This energy source will "run out" when the Earth and moon become tidally locked.

Similarly, a hydroelectric dam is ultimately powered by the sun. Gravity's involvement is just in transporting the water up and down. This is also similar to a typical steam engine, where a pump transports the steam, but the boiler is what supplies the energy to run the turbine. Well the moon can be in the sky at any time, not just at night, but this is also a peculiar question. The phrase "lunar activity" has no meaning that I can discern.

Tides are on a daily cycle (with two peaks) that changes very little from day to day. The tides get stronger when heavenly bodies align and when the distance changes by a significant amount. Both of these occur on nearly monthly cycles (again, with two peaks).

Regardless, is energy being put in the waves as a result of the existence of gravity? If gravity is not influencing energy over the waves, then in theory a wave should have no physical impact on anything.(which we know is not true).

If the moon influences a wave to rise, and a turbine is under that wave, then that turbine rotates and generates energy as a direct result of the wave hitting it, what is the original source of energy?

Also let me ask this. Would there be such a thing as "Waves" if the Earth did not rotate or orbit around the sun. Putting aside the fact that it would freeze then burn on one side, if somehow the climate was maintained, would there be waves? and if so were would the energy be coming from.

Gravity is not instantaneous, it travels at c.

I'm pretty sure this is a heavily debated issue
[off topic portion deleted]

 

[russ_watters]

Regardless, is energy being put in the waves as a result of the existence of gravity? If gravity is not influencing energy over the waves, then in theory a wave should have no physical impact on anything.(which we know is not true).

No. Energy is being put into waves due to the rotation of the earth. The tidal force creates a bulge, but that bulge would be stationary if the Earth was not rotating. The rotation of the Earth causes it to move, moving water around the Earth in a large wave, with countless secondary effects.

If the moon influences a wave to rise, and a turbine is under that wave, then that turbine rotates and generates energy as a direct result of the wave hitting it, what is the original source of energy?

The rotation of the earth. Unless the moon appeared and disappeared repeatedly in the same spot, what you describe could not happen without the rotation of the earth. There would be no rising and falling.

Also let me ask this. Would there be such a thing as "Waves" if the Earth did not rotate or orbit around the sun.

Yes, certainly. Most waves (on water) are caused by wind, not the tides.

[re: speed of gravity] I'm pretty sure this is a heavily debated issue.

No, it isn't. At least, not among real scientists. It is a component of Einstein's General theory of Relativity. Virtually everything you have said about its implications is wrong. Read the wiki on "speed of gravity" and ask any questions you still have in the Relativity forum. It isn't relevant to this topic. For that matter, this topic isn't engineering, it is astronomy. So I'm moving the thread to astronomy.

 

[Chronos]

Ocean waves slow the Earth's rotation over time regardless of whether we harvest their energy, or not. In that sense it is 'free' energy. Please note the term 'tidal waves', as used by SA's in this thread, are not the same thing as tsunami. The two are totally unrelated. 'Tidal waves' are generated by the gravity of the moon and sun, tsunami are generated by plate tectonics and colossal landslides.

 

[sophiecentaur]

Regardless, is energy being put in the waves as a result of the existence of gravity? If gravity is not influencing energy over the waves, then in theory a wave should have no physical impact on anything.(which we know is not true).

Of course gravity is relevant to the phenomenon of tides and tidal energy (the forces involved are gravitational) but it is not the 'source' of energy any more than the gearbox of a car is the source of energy to drive it forward.
Your statements seem to be somewhat 'tangential' to the actual Science involved. If you use the accepted terminology then you may find the subject more accessible.

 

[zeromodz]

Gravity is not instantaneous, it travels at c.

He is right, gravity does travel at c. No information can travel faster than light. The graviton would need imaginary mass to travel faster than c.

 

[russ_watters]

Let's try to circle back around the question in the OP. The OP asked about hydroelectric turbines using underwater to generate power. AFAIK, there are three related types:

1. Turbines at the bottom of a river.
2. Turbines in an ocean current such as the Gulf Stream.
3. Turbines at the mouth of a large bay, generating power as the tides cause the bay to fill and empty.

All three can generate power for a very long period of time. The first is powered by the sun transporting water from the ocean to land through the atmosphere. The second may be powered by a combination of the sun and the rotation of the Earth due to the coriolis effect, depending on the particular current. The third is powered by the rotation of the Earth moving the tidal bulge around the earth.

The OP also mentions waves. None of the above devies generates energy from regular ocean waves. Ocean waves do not involve any mass transport and therefore to harness them, you have to harness the oscillation itself: you have to use some kind of bobbing device (or tiny turbine) on the surface. However it is done, normal waves are powered primarily by the wind, which is powered by the sun. And they are in most cases not really related to the tides. In other words, it is not really correct to call motion of water due to the tides a "wave": the term "tidal wave" is a colloquial term, not a scientific one.

I don't see how terms like "seemingly infinite" in the OP are useful to discuss, much less argue about. It should be clear to everyone that there are no truly infinite sources of energy available to us, but there are sources of energy that have such longevity that they will certainly outlive us. For practical purposes, that's all that is required.

But the clarification made several times above is important to understand: "gravity" is not an energy source, infinite or otherwise.

 

[sophiecentaur]

I sail a lot in the Solent. There are regular (even during neap tides) fast tidal currents there (four times a day) and I'm convinced that a set of turbines under the water could produce oodles of energy. Of course, there's the problem of shipping (me included).
It seems to me that there are many advantages; they are not an eyesore, they are protected from the ravages of the weather, there is no problem of silting which happens with 'estuary / gravitational potential energy' systems and I can't imagine any other serious environmental issues. There are some systems for yachts that use water turbines rather than wind turbines and they work well (afaik) although they are more expensive than the wind variety.
Edit - second thoughts on the silting - there can be some surprising effects on sandbanks but these things could be re-sited if necessary (?).

 

[stewartcs]

...Ocean waves do not involve any mass transport...

Ocean waves do involve some mass transport IIRC (e.g. Stokes drift).

CS

 

[Xtensity]

Let's try to circle back around the question in the OP. The OP asked about hydroelectric turbines using underwater to generate power. AFAIK, there are three related types:

1. Turbines at the bottom of a river.
2. Turbines in an ocean current such as the Gulf Stream.
3. Turbines at the mouth of a large bay, generating power as the tides cause the bay to fill and empty.

All three can generate power for a very long period of time. The first is powered by the sun transporting water from the ocean to land through the atmosphere. The second may be powered by a combination of the sun and the rotation of the Earth due to the coriolis effect, depending on the particular current. The third is powered by the rotation of the Earth moving the tidal bulge around the earth.

The OP also mentions waves. None of the above devies generates energy from regular ocean waves. Ocean waves do not involve any mass transport and therefore to harness them, you have to harness the oscillation itself: you have to use some kind of bobbing device (or tiny turbine) on the surface. However it is done, normal waves are powered primarily by the wind, which is powered by the sun. And they are in most cases not really related to the tides. In other words, it is not really correct to call motion of water due to the tides a "wave": the term "tidal wave" is a colloquial term, not a scientific one.

I don't see how terms like "seemingly infinite" in the OP are useful to discuss, much less argue about. It should be clear to everyone that there are no truly infinite sources of energy available to us, but there are sources of energy that have such longevity that they will certainly outlive us. For practical purposes, that's all that is required.

But the clarification made several times above is important to understand: "gravity" is not an energy source, infinite or otherwise.

I know there isn't such a thing as infinite anything in this finite universe, but I was asking for an explanation of why gravity is not if it has an effect on the size of the waves. I know it isn't infinite, I was asking for an explanation on why.As for what zeromodz said, saying no information travels faster than the speed of light implies that the photon is the lightest particle? right? The photon has a mass, I don't understand why there can't be a particle lighter than a photon. If it was lighter than a photon would it not travel faster than the photon? I want to know why this is wrong since you all are saying nothing travels faster than light.

 

[stewartcs]

I know there isn't such a thing as infinite anything in this finite universe, but I was asking for an explanation of why gravity is not if it has an effect on the size of the waves. I know it isn't infinite, I was asking for an explanation on why.

You need to read up on gravity waves. That should explain how gravity plays a role in the phenomenon but isn't the source of the energy.

As for what zeromodz said, saying no information travels faster than the speed of light implies that the photon is the lightest particle? right? The photon has a mass, I don't understand why there can't be a particle lighter than a photon. If it was lighter than a photon would it not travel faster than the photon? I want to know why this is wrong since you all are saying nothing travels faster than light.

Photons do not have mass .

CS

 

[Xtensity]

You need to read up on gravity waves. That should explain how gravity plays a role in the phenomenon but isn't the source of the energy.

Photons do not have mass .

CS

Well the wiki page should be corrected then if I am going to be directed at reading the wiki pages for photons and the speed of gravity.
This gov. paper says Gauge Bosons are "Mass m < 1 × 10^−18 eV"

http://pdg.lbl.gov/2009/tables/rpp2009-sum-gauge-higgs-bosons.pdf
1st page like 2nd line.

That weight for gauge bosons is on the photon page, while on the gauge boson page it says that all of the gauge bosons are under that weight(1 × 10^−18 eV"), except for the photon which is massless.

and russ told me

Please read the wiki on "speed of gravity" as well as the wiki for "photon".

If the photon wiki has inaccurate data and I'm being told to get my data from there by russ, then others are telling me it's wrong... it should be clarified/fixed.

So the photon page should be corrected? Why is the mass on the photon page saying > 1 × 10^−18 eV if we are positive it is massless, unless there is a degree of uncertainty.

 

[Borek]

Why is the mass on the photon page saying > 1 × 10^−18 eV if we are positive it is massless, unless there is a degree of uncertainty.

As far as I can tell it says < 10^-18 eV, not > 10^-18 eV. And zero is for sure less than 10^-18.

 

[Xtensity]

As far as I can tell it says < 10^-18 eV, not > 10^-18 eV. And zero is for sure less than 10^-18.

Sorry about that. I mixed up my < and > signs. If you look at my first and second main paragraphs you can see I intended less than.

This gov. paper says Gauge Bosons are "Mass m < 1 × 10^−18 eV"

under that weight(1 × 10^−18 eV")

That > at the end was a mistype on my behalf. Can you you confirm that the photon mass on that wiki page should be zero and not < 1 × 10^−18 eV if we know that it is massless?

Why does it have that uncertainty weight if we know it is massless? If this could be explained then this would fix my entire confusion of why I thought gravity could be instant... If you can explain that I'll be able to understand my mixup about the previous misconception about gravitational waves.

 

[Borek]

Simplest explanation - in GR photon is massless, best measurements confirm its mass is below 10^-18 eV.

 

[Xtensity]

If we measure and can confirm its mass is under 10^-18 eV, then where did the notion that it's massless come from if we can only confirm that it is under a specific mass? Er more specifically, what in GR measured/estimated the photon to be massless?

 

[russ_watters]

"massless" is not something you can really measure since no measurement is exact so the best a measurement can get is close to zero.

You're really reaching here. If you really read the wiki, you'd see that it states in crystal clear terms that the photon is massless.

It also discusses the historical development - where the idea that it is massless came from. (it is a consequense of Maxwell's theory)

 

[russ_watters]

Ocean waves do involve some mass transport IIRC (e.g. Stokes drift).

CS

I'm not clear on if that is a function of the wave motion itself or if it is a biproduct of wind friction on the water surface or even a combination of both. Point taken, though.

 

[Xtensity]

The wiki says the photon is currently believed to be massless.

Then it also says

If the photon is not a strictly massless particle, it would not move at the exact speed of light in vacuum, c.

Isn't the entire point of the speed of light, being the speed of a photon. Wasn't the speed of light derived from the potential notion that the photon was massless, if the photon was massless then the speed of light would be stop speed. Meaning if it was not truly massless, then another particle could exist that travels faster than the speed of the photon... also I have read the speed of light wiki page and am aware of the precision we can measure to, though measurements are simply certain units of size that we have quantified in order to measure with. Meaning there can very easily be units smaller than what we can currently measure.

This is also because the speed of light can not be the perfect speed. Saying math is absolutely true is unscientific; Math just corresponds very close to exact objects it nature, which is why it is so reliable on the scale which we use it. How can precision ever be ensured when you start getting to such smaller measurements. Because in fact, if the photons mass is so small, and there does exist a lighter particle traveling faster than the photon, then how would we know because it could very easily be to fast for us to measure it. Just as, several decades ago, quarks and other particles existence were to small to be measured.

How do we know this is not the case?

Basically I think what I'm trying to ask is, if we derived the speed of light from measuring the photon, how do we not know if there is particles out there, hypothetically 1000x smaller than a photon, meaning they would travel much faster than the measured speed of the photon, we just can't measure them and currently have trouble detecting them.

How else would we come up with the speed of light besides measuring a particle which we thought was massless, if the photon truly had some excruciatingly small mass that we just say to be massless, what is stopping another particle from existing that is smaller which we can't measure yet?

 

[Borek]

Iwhere did the notion that it's massless come from if we can only confirm that it is under a specific mass?

Theory.

When you are checking things experimentally you can only do the experiment with a finite accuracy. That means you can never say "exactly zero" but "zero within the accuracy of the experiment". Best experimental accuracy so far proved mass is below 10^-18 eV.

Similarly - when talking about mass, we in fact talk about two different properties of matter, inertial mass and gravitational mass. Seems like they are identical - but experimentally we were so far able to prove it "only" with accuracy around 10^-12 (that was result of Braginski & Panow from 1972, could be there are better results available now).

 

[Xtensity]

Theory.

When you are checking things experimentally you can only do the experiment with a finite accuracy. That means you can never say "exactly zero" but "zero within the accuracy of the experiment". Best experimental accuracy so far proved mass is below 10^-18 eV.

Similarly - when talking about mass, we in fact talk about two different properties of matter, inertial mass and gravitational mass. Seems like they are identical - but experimentally we were so far able to prove it "only" with accuracy around 10^-12 (that was result of Braginski & Panow from 1972, could be there are better results available now).

Yes I understand that, but I don't understand what's preventing smaller particles from existing. If the speed of light is the measured speed of a photon, to as much accuracy as we can measure, would lighter particles not travel faster? If not, why would they not travel faster. Btw please don't interpret this as me trying to "debunk" science, because that's what people have said that's what it appears I'm doing, but I am not, I am trying to get a clear picture, when thoughts/questions pop in my head on various subjects.

 

[Borek]

Yes I understand that, but I don't understand what's preventing smaller particles from existing.

You want them to have mass lower than zero?

Massless photon is part of a theory that is already over 100 years old, during this time it was successfully tested over and over. It doesn't mean theory is 100% sure - single, reproducible experiment that will give results differing from predicted is enough to show the theory is limited. But there was no such experiment, quite the opposite - countless experiments proved theory is valid. So it is not only best we have, we are also trying it for over 100 years - and so far we fail to invalidate it.

Note that experiments that try to measure photon mass are in fact trying to invalidate the theory - IF the results of some experiment will be 7+/-2 it will be obvious we were wrong But so far it seems like photon is massless with a very high accuracy.

 

[Xtensity]

There's key words here though. Very high accuracy, "seems like". Of course with such its fragile size that we can not measure it perfectly, as the probability of that is very low. Though I am confused in the area of, if we are so sure that it is massless, then why is there that area of uncertainty?

I realize that the point of experiments is to try to disprove theories, meaning if these attempts to disprove keep failing then the area of certainty increases. When you simply look at the mass range we have confirmed that it IS under a certain mark, but how much lower can it go? Is there a scientific point that separates 0 mass from "> 0" mass? Numbers are an invention to quantify things in reality which has lead us to development of higher mathematics

Massless, means without mass, meaning 0. I very well see the point you are making but the speed of light is based off the photon which we have tested over and over again. How are we supposed to confirm 0 mass. We can't. All we can do is keep experimenting and testing with smaller and smaller numbers, into higher and higher decimal places. There's no doubt that the mass of a photon is under a certain mark, but I fail to see where such a level of certainty comes from that it is completely massless. Surely it would be unscientific to say that it is entirely massless? Of course we can agree that it is under a certain mark, which we can confirm and test, but saying it is completely massless, is a very big claim considering how small numbers can get...infinitely small... which almost represents a logical paradox in itself.

Think of it this way. As technology advances, we are able to measure to higher degrees of uncertainty as the numbers get smaller and smaller. Recently in the past 38 years the level of certainty about Light Speed had increased by 100x. Meaning, what is to prevent technology from continually advancing. We can keep estimating it smaller and smaller, but how small can we go? Do we just assume that it is massless because the range which we can measure it to be under is so small?

How can something that is massless be measured? The only thing we know with a very very high accuracy is that it is under a specific very small range, we can confirm this with test.

Countless experiments only prove that the theory is extremely accurate. For it to be proven 100% valid(that the photon is massless), we would have to be able to measure to infinitely small numbers, can we agree on this? That there IS a level of uncertainty. Meaning that there IS a chance that the speed of light is not top speed, but only the speed of particles with the mass of a photon. Meaning if there is a chance that the photon is not massless, then there could be particles which have less mass, meaning they travel faster. Can we agree on this part? You just said yourself, it doesn't mean the theory is 100% true and accurate, but it is extremely accurate. You must keep in mind how small values can actually go and how small we can currently quantify.

With this all being said, 'is' there a possibility that there could be a particle lighter than a photon, if the photon was not massless. We can't confirm masslessness, we can only confirm mass under a very small range.

Or if what I have said is all wrong, how have we jumped from "range that its beneath" to masslessness... and this can not be based off comparing measurements to light speed as the max speed, because the notion of light speed being the universal speed limit is founded on the notion that the photon is massless, which would in turn be circular reasoning. Also before you misunderstand me, I am agreeing with you on the fact that we can't measure to 100% precision, but we CAN measure it to a very small range... I'm just confused as to why we assume its massless(besides aforementioned speed of light reason)

 

[Blenton]

Photon has energy. E = mc^2. Therefore photon has mass.

 

[Xtensity]

Photon has energy. E = mc^2. Therefore photon has mass.

See this is where I get confused to a degree. That formula is based on a constant which is derived from a measured speed of a photon.

If c is just the speed of the photon, and the photon has a mass.. If there exist a particle lighter than a photon, then why would we still use C as what it currently is? Or am I misunderstanding something?

Edit: Would this insinuate that we do have a very accurate measure for energy, but the discovery of a lighter particle would also lead to discoveries of a higher speed, which would inturn lead to more accurate predictions of energy content(to higher decimal places)... Since the formula is the energy more or less as mass approaches the limit of 0?

 

[russ_watters]

There's key words here though. Very high accuracy, "seems like". Of course with such its fragile size that we can not measure it perfectly, as the probability of that is very low. Though I am confused in the area of, if we are so sure that it is massless, then why is there that area of uncertainty?

That's just how science works: no measurement can ever be 100% accurate and no theory can ever be 100% proven. So the best we can do is 99.9999999999999% certain.

 

[Xtensity]

That's just how science works: no measurement can ever be 100% accurate and no theory can ever be 100% proven. So the best we can do is 99.9999999999999% certain.

I realize exactly that, which is why we can only measure to a certain level of mass accuracy.

Does that not defy the Mass–energy equivalence formula to say that the photon is massless, when the formula says otherwise? We know the photon has energy.

Isn't it unscientific to say the speed of light is the top speed? Wouldn't it be more accurate to say it's the highest speed we can measure, but there very easily could be higher speeds if lighter particles existed that we don't have the current technology to measure? I'm sure everyone can agree it will always be unscientific to say we've reached the peak of universal discoveries.

 

[n.karthick]

I'm just confused as to why we assume its massless(besides aforementioned speed of light reason)

Reading a physics book and understanding the theory first before jumping into doubts/conclusions can solve all your confusions.

What is discussed till now is 100 years old theory and if you comprehend it, you will be in a better position to ask right questions. All the best.

 

[russ_watters]

Does that not defy the Mass–energy equivalence formula to say that the photon is massless, when the formula says otherwise? We know the photon has energy.

That formula is not saying the photon has mass. That's a common misuse of the formula.

Isn't it unscientific to say the speed of light is the top speed?

Of course not! A theory predicts it, all evidence we have to date validates the theory, and no other theory exists that can explain the evidence. That's perfectly scientific.

Wouldn't it be more accurate to say it's the highest speed we can measure, but there very easily could be higher speeds if lighter particles existed that we don't have the current technology to measure?

Certainly not. There is no theory that predicts a non-zero mass for the photon that doesn't contradict the evidence we already have.

I'm sure everyone can agree it will always be unscientific to say we've reached the peak of universal discoveries.

Of course. That's not what's being claimed. What you're claiming is no less profound: That a 100 year-old, exquisitely well proven theory is wrong. That would be Earth'shattering.

 

[Xtensity]

Russ I understand what you're saying, but why is there that area of uncertainty.

Yes there are countless test reverifying that the mass of a photon is very small. Just because no theory exist predicting otherwise does not mean that 'otherwise' isn't true. If a smaller mass, under the already known range, were predicted, that wouldn't contradict the current test done on the speed of light.

I'm baffled at the level of certainty that exist for something so small. I mean, I can completely understand the it being measured under <1×10−18 eV, because we can confirm this.

But we can not confirm masslessness, we can only predict really close to it, which is why it baffles me that we can just say, there is no mass. We can't verify no mass, it's logically impossible, we can only verify extremely small masses.

Edit: you also say

Of course. That's not what's being claimed. What you're claiming is no less profound: That a 100 year-old, exquisitely well proven theory is wrong. That would be Earth'shattering.

I'm not saying the proven theory is wrong. In fact, I wouldn't use the word proven. All the test that have been done only reassure us that it lies under a certain range. It does not prove massless, it only proves that it is under a certain range.

Or unless you know of a way to measure, the lack of mass. Which would have to go on the assumption that we can measure things infinitely small, which we can't, there's limits to our technology, this fact can not be argued, the method can though. So if you have some method I am unaware of for measuring masslessness or infinitely small numbers, please do post it.

 

[russ_watters]

Russ I understand what you're saying, but why is there that area of uncertainty.

We're starting to go in circles here: It is a combination of logic and measurement imperfection. The uncertainty in the measurement exists because it is impossible to have 100% measurement accuracy. At the very least, measurement devices are man-made and therefore have flaws that can never be completely eliminated.

And logically, the uncertainty in the measurement plus the fact that you can't ever measure the speed of every photon means that you can't ever prove that every photon moves at C.

Do not make the mistake of believing that this little opening is a place where scientists should be looking to build a theory of a massive photon. It's simply a demonstration of the level of scientific certainty and its limits.

Yes there are countless test reverifying that the mass of a photon is very small. Just because no theory exist predicting otherwise does not mean that 'otherwise' isn't true.

Of course: Being 99.999999999% sure of one thing means there is a 0.0000000000001% chance that there is something being missed.

But we can not confirm masslessness, we can only predict really close to it, which is why it baffles me that we can just say, there is no mass. We can't verify no mass, it's logically impossible, we can only verify extremely small masses.

That's not quite right. First, the prediction is masslessness. I think you meant measurement: A measurement would say something like 0.01 +-.02, which verifies that the mass is somewhere between -.01 and +.03. .03 is an upper bound in the range. So the experiment verifies no mass (because 0 is inside that range) to within a certain accuracy.

 

[Xtensity]

We both agree there is that level of uncertainty. Can we agree that the possibility for a very small mass of a photon does exist, we just can't measure it? The theory of a "massive photon" would not contradict any theories, other than the notion of it being massless(which can't be 100% accurate obviously).

I'm not trying to establish any scientific theories here, just trying to establish that the possibility 'does' exist. It's talked about as if it's nonexistent, when it very well may be measurable in the future.

(also if you want to take the time, could you clarify why "That's a common misuse of the formula.", so I can understand for future references)

 

[DLuckyE]

Isn't mass just energy in a different form? And a photon is just energy? Which would make it impossible for a photon to have mass(per definition that is)?

 

[Xtensity]

Isn't mass just energy in a different form? And a photon is just energy? Which would make it impossible for a photon to have mass(per definition that is)?

That would clarify a lot if true, but if that's true, then what is the entire point of attempting the measure the mass of a photon?

 

[xAxis]

I think this shouldn't really be discussed here, but well. No theory can be 100% proven. The entire point of measuring the mass of a photon is in my opinnion that it would disprove the theory "directly".
And I think this is the mistake:

"The theory of a "massive photon" would not contradict any theories, other than the notion of it being massless"

The theory is not just one notion. Measuring the mass of a photon would disprove the entire theory of relativity, and probably some other things and concepts too.

 

[Xtensity]

I think this shouldn't really be discussed here, but well. No theory can be 100% proven. The entire point of measuring the mass of a photon is in my opinnion that it would disprove the theory "directly".
And I think this is the mistake:

"The theory of a "massive photon" would not contradict any theories, other than the notion of it being massless"

The theory is not just one notion. Measuring the mass of a photon would disprove the entire theory of relativity, and probably some other things and concepts too.

It wouldn't disprove the theory of relativity because we have already tested it and can verify a large portion of it. It may alter the theory, but that's it.

If a photon mass was discovered then it could lead to the discovery of other particles, which would make it so there would be better numbers to use than c in the mass equivalence formula... but the overall measure of the amount of energy would only change slightly. It would expand the formula or open up another formula for use.

The discovery of a potential massive photon would not destroy all of the current theory of relativity, I don't understand how you can say that when a majority of it has already been proven. All it would do is redefine it and make it more accurate.

Edit: If you haven't realized, Massless is not an undefinable number, massless means 0. Think of it this way, if a mass was discovered for a photon(smaller than we can currently measure obviously), then it would just move the scale up slightly. I don't see how you can say it would destroy the entire theory.

 

[xAxis]

I am not an expert on R.T., but am pretty sure it would destroy it, someone might back me on it. But again, it really shouldn't be discussed under this topic.
Also you should understand that no theory can be 100% proven, that's how physics works.

 

[Xtensity]

I am not an expert on R.T., but am pretty sure it would destroy it, someone might back me on it. But again, it really shouldn't be discussed under this topic.
Also you should understand that no theory can be 100% proven, that's how physics works.

I understand no theory can be 100%.

If it would destroy it, I am curious as to why, because from my PoV that doesn't seem like it would happen, but I'm probably wrong..

 

[Jack21222]

Of course it's possible that photons have mass. It's also possible that I'll quantum-tunnel my way into your room after I make this post to tell you that in person.

I am not aware of any coherent theories that predict a massive photon. When you come up with one, let us know. Otherwise it makes no more sense to talk about a massive photon than it does to talk about a 5-headed unicorn that lives underneath the Gobi desert.