a Thinking Man's discussion

[galaxyblur]

Wow, a busy day at work and look what I've missed

 

Thank you all for your responses, I will try to read them thoroughly in the morning. I have glanced over a few though...

 

lucaspa, I first assumed and will always assume that it is from a lack of knowledge that I personally cannot explain this apparent situation. I think much confusion has come from the fact that I am not a scientist, and although I read and study as a hobby, this is obviously a limited scope from which to make an argument. Hence, I am here seeking second opinions. If I thought I had all the answers, I would never have needed to post in a forum such as this

 

In the same way I could not speak to you in terminology and semantics native to my profession and expect you to grasp it all, I am not in a 100% "scientific" mindset. I have my roots in art and philosophy, and this is my perspective towards science.

 

When I say "law of nature", I am not referring to laws that we have created from data that pertain to certain experiences and not necessarily others. I mean, nature's true self... the "universal constant", GUT's, TOE's, etc. Things we have not yet begun to understand, but I greatly desire to understand them. If there is a better term I should use rather than "law", please enlighten me.

 

And, I know that Einstein took Galileo's Relativity Principle and expanded upon it 10-fold, but you also must realize that Galileo's principle and Einstein's theory are vastly different things. Galileo constructed not only a scientific principle, but a philosophical one as well.... it reaches beyond the realm of science. Kind of along the lines of Existentialism. One of those things that makes SO much sense, it MUST be true. It reaches beyond proofs and data; it is simply the only possible outcome.... kind of like Darwin's Evolution. So, with no disrespect to Einstein or his contemporaries, I don't think SR or GR should have to enter into this equation at all. They involve many more complexities, and I think Einstein would agree that simplicity and minimalism is the universe's true nature. Occam's Razor, etc. Perhaps we have come full circle (E=MC2 style), or perhaps not.

 

So, I hope you're all enjoying this discussion and are not just trying to thwart me away from your forum and shut me up Because I'm enjoying trying to see things from your angle. So, not to use a bad pun, but please humor my perspective and bear with me.

 

Like I said, I'll read your responses more thoroughly in the morning.

[someguy]

actually einstein was very much philosophical he came up with his theories by doing thought experiments not tests in a lab or strictly mathematical formulas in fact it wasn't until later that we had the proper tools to be able to test his theories. And I think it was partially because of this that he had alot of trouble getting his theory accepted by many in the scientific community.

[swansont]

but i think your mass does change, relative to other objects that did not partake in the same acceleration you did. no? matter is energy.

 

But as you cannot be in their frame of reference, it's irrelevant. You never see your own mass changing. You are always in your own frame of reference.

 

maybe i should have said accelerated. granted if you look at two moving objects you could not know that one is stationary and the other isn't, they are both moving compared to each other. but if they were the same mass when moving at the same speed and you accelerated one of them this would be an identifiable thing no? because otherwise if a spaceship accelerating away from earth increases in mass then so would the earth and that doesn't make a lick of sense to me since no energy was added to the earth. and in this thought experiment one of the balls never accelerated and therefore would never have altered its mass/energy and the other ones would have traded speed and mass assuming they were all the exact same mass when at relative rest.

 

As has been discussed here and in another thread, conservation of energy does not apply when transforming from one frame of reference to another. The "extra energy" the external observer sees isn't a valid comparison.

 

So basically if I am just traveling in space for example and I come upon a asteroid traveling in space the only thing I can understanding at that point is purely relational to my position and other variables such as maybe whatever speed I am traveling at?

 

To me it sounds like such goes along on some degree basically with the uncertainty principal, am I generalizing to much?

 

All you can say is the asteroid is moving relative to you. You might consider yourself to be moving, but there's no experiment that can show that you are the one that's moving, in an absolute sense — whatever test you run will work out the same in another frame of reference. The best you can do is determine motion relative to something else.

 

One of those things that makes SO much sense, it MUST be true.

 

There have been a number of things that make SO much sense, that they must be true, and weren't. Everybody agreed that heavier things fall faster, that the earth was the center of the universe, that space and time were absolute, because that made SO much sense.

 

But in science you have to test these things, try and falsify them, before you can have any real confidence that they are, in fact, true.

[galaxyblur]

actually einstein was very much philosophical he came up with his theories by doing thought experiments not tests in a lab or strictly mathematical formulas in fact it wasn't until later that we had the proper tools to be able to test his theories. And I think it was partially because of this that he had alot of trouble getting his theory accepted by many in the scientific community.

 

good point. very true, and I admire that side of him.

 

There have been a number of things that make SO much sense, that they must be true, and weren't. Everybody agreed that heavier things fall faster, that the earth was the center of the universe, that space and time were absolute, because that made SO much sense.

 

But in science you have to test these things, try and falsify them, before you can have any real confidence that they are, in fact, true.

 

I'll concede that there is a chance that relativity is an illusion or just an artifact of our ignorance about the universe, but I personally don't believe that is the case.

 

according to Relativity though, you could say that the Earth is the center of the universe and you'd be just as correct And heavier things do fall faster, its just not noticeable to us because they're so small compared to the Earth. But perhaps that's another thread

[swansont]

I'll concede that there is a chance that relativity is an illusion or just an artifact of our ignorance about the universe, but I personally don't believe that is the case.

 

according to Relativity though, you could say that the Earth is the center of the universe and you'd be just as correct And heavier things do fall faster, its just not noticeable to us because they're so small compared to the Earth. But perhaps that's another thread

 

Non-sequitur, no, and no.

[galaxyblur]

Non-sequitur, no, and no.

 

Please explain your non-sequitur comment...

 

As far as the Earth being the center of the universe, perhaps it depends on your definition of universe.

 

 

and according to this thread:

 

http://www.scienceforums.net/forum/showthread.php?t=27466

 

I am not the only one to make such a claim about gravity.

[swansont]

Please explain your non-sequitur comment...

 

As far as the Earth being the center of the universe, perhaps it depends on your definition of universe.

 

 

and according to this thread:

 

http://www.scienceforums.net/forum/showthread.php?t=27466

 

I am not the only one to make such a claim about gravity.

 

Conceding that relativity may be an illusion would not seem to bear any relation to my comment. Relativity has been tested, and passed those tests, replacing the Galilean view that made sense to a lot of people. Something that made a lot of sense was wrong. Special relativity is not intuitive to many; it does not make sense. (if you're referring to something other than that when you say "relativity" then you need to be more clear. That's how it is generally taken.)

 

"Universe" doesn't really have much latitude in its definition, but making an argument true by changing the definition of a word is equivocation, which is a logical fallacy.

 

The conclusion of the linked post is that the feather and hammer fall at the same speed (they have the same acceleration); if they are dropped simultaneously they will hit at the same time. Making a claim is irrelevant. I can claim the moon is made of cheese. Anyone can make an incorrect claim.

[galaxyblur]

Conceding that relativity may be an illusion would not seem to bear any relation to my comment. Relativity has been tested, and passed those tests, replacing the Galilean view that made sense to a lot of people. Something that made a lot of sense was wrong. Special relativity is not intuitive to many; it does not make sense. (if you're referring to something other than that when you say "relativity" then you need to be more clear. That's how it is generally taken.)

 

when i say relativity, i'm referring to the principle. the theory merely expanded upon the principle and used it as a postulate, but did not replace it. Galilean Relativity did make sense to a lot of people (including Einstein) and still does make sense. It was never wrong.

 

"Universe" doesn't really have much latitude in its definition, but making an argument true by changing the definition of a word is equivocation, which is a logical fallacy.

 

The definition of universe gets changed all the time. Its an abstract idea. How would you define it?

 

The conclusion of the linked post is that the feather and hammer fall at the same speed (they have the same acceleration); if they are dropped simultaneously they will hit at the same time. Making a claim is irrelevant. I can claim the moon is made of cheese. Anyone can make an incorrect claim.

 

It was stated in the thread that they must accelerate at different rates, but perhaps immeasurably different. Someone went on to say that there was once a heated thread on this very topic. So I can't be the only one ever to make that "claim".

[someguy]

But as you cannot be in their frame of reference, it's irrelevant. You never see your own mass changing. You are always in your own frame of reference.

 

I see your point. but you could still for one notice that one of the balls changes mass and the other doesn't. I think this is just a difficulty of measurement right? because you yourself and everything else pegged in your frame all increases in mass. but.. i'm wondering if you couldn't.. if you could accelerate two objects of equal rest mass exactly evenly, wouldn't they spontaneously begin to accelerate towards one another as their speed increases (or rather increase their acceleration rate towards each other) even though you only apply the force in a direction that would cause the two objects to travel parallel to each other? because as their mass increases they attract each other more and more. if this is so then it would be possible to test your increase in mass. because though mass is not quantity of matter and becoming more massive is not equivalent to adding matter to yourself, mass does cause warping of space/time and therefore you could simply define mass as being propensity to warp space/time, and since E=mc^2 mass is equivalent to energy, and therefore energy warps space/time, and that means that increasing the kinetic energy of an object will cause that object to increase the bend it causes in space-time and you could measure this increase in the slope of the warped space time. is that not right?

 

on earth all objects accelerate at the same rate, granted. but on the moon they don't accelerate towards the center of the moon at the same rate as they would accelerate towards the center of the earth. this is because there are no objects on earth that are significantly massive enough compared to each other to make a difference but the moon is so much less massive than the earth you can notice the difference. adding speed to an object increases its mass and thus the slope of the disruption in space-time it is causing, and therefore if you accelerated the earth significantly enough, things would not accelerate at 9.8m/s^2 anymore but at some faster rate of acceleration, same thing if you could super heat the earth enough. if mass was not an issue than shouldn't we weigh the same thing on the moon as we do on earth?

 

I think we could just say instead that you could have a clock on board and the pool balls could have clocks on them and you could know by watching your clock compared to theirs which pool balls are trading kinetic energy with one another. the point is that adding energy whether it be motion or heat or anything changes an object and you can identify what is going on independently from any frame of reference.

[swansont]

when i say relativity, i'm referring to the principle. the theory merely expanded upon the principle and used it as a postulate, but did not replace it. Galilean Relativity did make sense to a lot of people (including Einstein) and still does make sense. It was never wrong.

 

And it replaced Aristotle's view, which was held as making SO much sense for a very long time. Until it was tested, and found to be in error. Galilean relativity principles are tested; they are not accepted solely because they make sense. And things that make sense are sometimes wrong, which was my point earlier; making sense cannot be equated with valid science.

 

The definition of universe gets changed all the time. Its an abstract idea. How would you define it?

 

All matter and space.

 

It was stated in the thread that they must accelerate at different rates, but perhaps immeasurably different. Someone went on to say that there was once a heated thread on this very topic. So I can't be the only one ever to make that "claim".

 

There are some subtle variations in how those problems can be worded, and if one does not define terms precisely, that's what can happen. But all of that is irrelevant. People claim that quantum mechanics, evolution, and other things are wrong. There is no scientific value in observing that there are claims. Science is not a democracy, it is a meritocracy. The claims have to have merit.

[lucaspa]

When I say "law of nature", I am not referring to laws that we have created from data that pertain to certain experiences and not necessarily others. I mean, nature's true self... the "universal constant", GUT's, TOE's, etc. Things we have not yet begun to understand, but I greatly desire to understand them. If there is a better term I should use rather than "law", please enlighten me.

 

Right now there is no better term and you are going to have to use "theories". "Law" was used historically by scientists precisely because they thought they had found "nature's true self". At the beginning of the 20th century it was found that "laws" were really well-supported theories and, as you said, constructed from data. When new data was found that didn't fit the "law" (such as velocities close to the speed of light), well, then, the "law" had to change. So now the term "law" isn't used anymore -- at least in physics and the other disciplines are catching up. We have the THEORY of Relativity and the THEORY of Quantum Mechanics. Both are as well confirmed as Newton's LAWS of motion, but we don't call them "laws" anymore.

 

One of those things that makes SO much sense, it MUST be true. It reaches beyond proofs and data; it is simply the only possible outcome.... kind of like Darwin's Evolution.

 

I'm glad you confessed that science is not your field. Therefore you won't be upset when I say that this is NOT the way to do science. The best description of how science operates is here:

 

"...what we learned in school about the scientific method can be reduced to two basic principles.

"1. All our theory, ideas, preconceptions, instincts, and prejudices about how things logically ought to be, how they in all fairness ought to be, or how we would prefer them to be, must be tested against external reality --what they *really* are. How do we determine what they really are? Through direct experience of the universe itself.

2. The testing, the experience, has to be public, repeatable -- in the public domain. If the results are derived only once, if the experience is that of only one person and isn't available to others who attempt the same test or observation under approximately the same conditions, science must reject the findings as invalid -- not necessarily false, but uselss. One-time, private experience is not acceptable." Kitty Ferguson, The Fire in the Equations, pg. 38.

 

As Swansont pointed out, no matter how "true" Galilean Relativity looks, it MUST be tested. If it doesn't correspond to what we observe, it is wrong.

"Galilean relativity principles are tested; they are not accepted solely because they make sense. And things that make sense are sometimes wrong, which was my point earlier; making sense cannot be equated with valid science. "

 

I think Einstein would agree that simplicity and minimalism is the universe's true nature. Occam's Razor, etc.

 

Again, several problems with your knowledge of science. Not all your fault, this misrepresentation of Occam's Razor is very common. The idea that the simplest answer is the correct one is actually the position Ockham argued against. This idea comes more from Newton. Ockham said "don't use any more entities than necessary to describe an observation" Ockham's example (from his own time) was:

1. An object moves because of an impetus.

2. An object moves.

 

Ockham argued that motion is change of position with time. The phrase "because of an impetus" was unnecessary and should be dropped.

 

In biology, we have found that simplicity is absolutely NOT "the universe's true nature." In fact, because of natural selection, organisms are unnecessarily complicated.

 

So, I hope you're all enjoying this discussion and are not just trying to thwart me away from your forum and shut me up

 

No. In fact Swansont gave the answer in more detail. I hope you can understand and accept it.

 

Swansont: "Universe" doesn't really have much latitude in its definition, but making an argument true by changing the definition of a word is equivocation, which is a logical fallacy.

 

The definition of universe gets changed all the time. Its an abstract idea. How would you define it?

 

All matter/energy and spacetime. That's pretty standard. Recently some scientists have been advocating larger structures such as Multiverse and Bubble Universe. If so, then instead of saying "universe" they will say "our universe", which is all the matter/energy and spacetime that we observe.

 

All you can say is the asteroid is moving relative to you. You might consider yourself to be moving, but there's no experiment that can show that you are the one that's moving, in an absolute sense — whatever test you run will work out the same in another frame of reference. The best you can do is determine motion relative to something else.

 

Can you always measure your movement in relation to the speed of light?

[someguy]

 

"...what we learned in school about the scientific method can be reduced to two basic principles.

"1. All our theory, ideas, preconceptions, instincts, and prejudices about how things logically ought to be, how they in all fairness ought to be, or how we would prefer them to be, must be tested against external reality --what they *really* are. How do we determine what they really are? Through direct experience of the universe itself.

2. The testing, the experience, has to be public, repeatable -- in the public domain. If the results are derived only once, if the experience is that of only one person and isn't available to others who attempt the same test or observation under approximately the same conditions, science must reject the findings as invalid -- not necessarily false, but uselss. One-time, private experience is not acceptable." Kitty Ferguson, The Fire in the Equations, pg. 38.

 

 

I agree that for a theory to be accepted by everyone it needs to be falsifiable and at some point tested. but i have never personally tested anything of the theory of relativity and i didn't believe it until i was logically convinced of it even though i knew it had been tested. the theory though may not be intuitive is logically undeniable. there are some arguments from the aristotle days that hold true today. the problem is some flaws in arguments are really hard to find and the only way to test them is by empirical testing. but you could easily, well not easily, but you could convince me of something without my testing it, and in fact if you can't do this then to me it's a little sketchy. it is kind of like the emperor's new clothes. is it just too complicated? or is it just bs. that's why i don't really like string theory because everybody can tell me what it is, nobody can tell me why, except maybe with some math but math alone, in my opinion is only as good as it is related to reality, if you mess up the relationship with reality it's just as good as a flawed argument, if you properly pegged it to reality you can make discoveries with math and not with any empirical tests or observations and that would be, in some cases, sufficient for me, but the thing is usually math gets tailored to properly represent observations and tests therefore a prediction of some untested thing could be wrong and in fact your equation is not complete for that contingency but still sometimes i would just trust the math even for things i can't test and logic too. but then again i am not science.

[galaxyblur]

someguy, I agree on all counts, whole-heartedly.

[someguy]

 

 

 

Can you always measure your movement in relation to the speed of light?

 

you can never determine your speed compared to the speed of light. if you could then light would seem to be at different speed compared to you, when you move at different speeds. this is not the case. so if you had a beam of light next to you and you suddenly accelerated really fast the light next to you would be still moving at the same rate compared to you than it was before. so compared to light you never moved at all. it always moves at roughly 3.0*10^8 m/s compared to you. but the faster you go the more energy you are. speed is energy and so adding speed you are adding energy, matter is energy and has mass, ie propensity to curve space time, adding energy does not add matter but adds mass, (since matter is energy that's not really a big surprise). and so by adding mass you add ability to curve space-time also not a surprise because that's what mass is by definition. in short energy curves space time all except for light which is somehow different. that's e=mc^2 unless i made a mistake but i don't think so. therefore it is possible to monitor differences in speed of objects independently of reference frames. but calculating your speed in absolute terms is never possible you need a reference point. And that can't be light because it remains static relative to you no matter how fast you go instead of remaining independently constantly pegged. nothing is independently constantly pegged, its all moving any which way. everything is relative... except for light. which seems contradictory but isn't. so the speed of light is constant but not constant enough in a way or too constant depending on how you look at it. it's a little confusing. but you know what i mean. it needs to not always constant compared to you but constant compared to the universe and nothing is like that or everything is like that because all you have to do is name one thing your reference point and there you go. but there is no universal one that will never change.

[swansont]

Can you always measure your movement in relation to the speed of light?

 

 

To the speed? No, since all inertial reference frames will give you that answer. Light isn't really in an inertial frame, as used in special relativity.

 

ince E=mc^2 mass is equivalent to energy, and therefore energy warps space/time, and that means that increasing the kinetic energy of an object will cause that object to increase the bend it causes in space-time and you could measure this increase in the slope of the warped space time. is that not right?

 

That's a good question and I'm not conversant enough in GR to give a good answer, but I think the answer has to be no. The amount of gravity can't rely on what frame the observer is in; gravity depends on rest mass and energy, but I think that translational kinetic energy is not included there. e.g. our orbits should not change for an observer travelling to/away from us at high speed, perpendicular to the ecliptic (so as not to have to worry about length contraction effects)

[someguy]

To the speed? No, since all inertial reference frames will give you that answer. Light isn't really in an inertial frame, as used in special relativity.

 

 

 

That's a good question and I'm not conversant enough in GR to give a good answer, but I think the answer has to be no. The amount of gravity can't rely on what frame the observer is in; gravity depends on rest mass and energy, but I think that translational kinetic energy is not included there. e.g. our orbits should not change for an observer travelling to/away from us at high speed, perpendicular to the ecliptic (so as not to have to worry about length contraction effects)

 

 

 

let's take this one step further. ok, velocity increases mass right? no problems there i add energy to the mass e=mc^2. now what happens if i slow the object down from its original velocity that i gave and is therefore precisely known to me. i spent energy on the object. where did that energy go? i would guess also that since the velocity would have decreased from before i decelerated it then we would have to say that it warps space-time less than it did before. now if that is true then there is energy unaccounted for, that i can tell, and more than that it also means than through trial and error (granted the possibilities would be literally infinite) you could find a point where the object would be warping space-time the least. and this would have to be speed zero. It is the speed where the only warping of space-time is done by matter itself and none of it due to velocity. Something here seems very wrong. when i first thought of this i was considering that maybe it was something to do with entropy in the way that you cannot reduce velocity, you cannot slow an object down, just move it in a different direction, but then i thought that couldn't be since einstein's e=mc^2 can be used to identify what new mass an object would have at a greater velocity. though, you need to enter the energy used to obtain that velocity i think,,, maybe that's a clue. hmm ya i think it is.. i think maybe if you accelerate an object and spend energy slowing it down again back to its original speed it would still have more mass. is that right? it seems to me like it must be. therefore any time an object moves it increases in mass no matter what the direction, and that means that mass can only go up and never down. therefore if you use light to propel objects you are creating mass that was never there, and since we'd have to assume that happens sometimes by fluke the mass of the universe must be increasing right? it seems also to maybe have some implications to the beginning of the universe. am i right to think that decreasing velocity also increases mass? it's making more and more sense to me that it must.

 

 

 

so i think since you can use e=mc^2 equation to determine the increase of mass an object gets from an increase in speed and that is kinetic energy so i think that kinetic energy does in fact increase the mass and thus the warp of space-time even if it is used to slow the object down if my conclusion of the previous post is right. but i certainly do agree with you that the frame you're in has no effect on your mass or the gravitational field you make, i'm not sure what exactly i said that made it seem like that's what i was saying but whatever it was i didn't mean it that way. the basic point was that by monitoring the mass of objects you can determine which ones traded energy or which ones got energy and which ones lost energy. and therefore you can't be fooled by the pool ball thing since you can clearly notice that one of the balls never received nor lost energy. and this would be completely independent of any frame of reference so you can't be fooled by a tricky frame. what happens is always what happens changing your frame never changes that.

[swansont]

But your approach implies a preferred reference frame — the frame where we can measure the gravitational attraction from the relativistic mass. That's the main flaw I see.

 

The terms that go into the stress-energy tensor are the four-momenta, the square of which is the invariant rest-mass. No kinetic energy term, because that is the result of a coordinate transformation, and that can't change the dynamics of the system.

[someguy]

first i said something something in my last post, i just realized that whatever is slowing down another object is the thing that receives the energy but still it could hold that the universe increases in mass continuously. but that would mean that there is a point where an object bends space-time less than it would at any other vector speed.

 

I am not sure exactly what you mean, but i feel that i don't have a preferred frame. i see what you mean about kinetic energy since if say for instance the reference frame is as it is in the pool ball experiment that is difficult to explain, we could not say the pool ball has kinetic energy since it would not be in motion according to that frame. If that is what you mean then in a way i agree, but this is only due to how we have defined kinetic energy. the fact remains that there was a transfer of energy of one pool ball to the other. you can name that energy whatever you want. but that energy will affect how the balls bend space-time and how they travel through time relative to each other. and these things are independent of your reference frame. if not, then the twin paradox couldn't work and also objects wouldn't get more massive as you transfer energy to them.

 

i don't see how changing your reference frame could change how a mass warps space-time, that seems independent of any frame of reference, though from some frames that warp and the object are moving and in others it doesn't. so perhaps in some you could say that there is kinetic energy but in others you would only be able to say that there was a sudden increase in mass.

 

maybe i totally misunderstood you because i don't understand this sentence: "The terms that go into the stress-energy tensor are the four-momenta, the square of which is the invariant rest-mass." unfortunately i don't know what a stress-energy tensor is or what the four momenta are, or the formula that says their square is the invariant rest mass.

[swansont]

i don't see how changing your reference frame could change how a mass warps space-time, that seems independent of any frame of reference, though from some frames that warp and the object are moving and in others it doesn't. so perhaps in some you could say that there is kinetic energy but in others you would only be able to say that there was a sudden increase in mass.

 

This implies that kinetic energy doesn't matter. How much KE something has depends on the reference frame you are in. And the KE is the increase in mass — they are different ways of describing the same thing. You can utilize one or the other, not both.

 

maybe i totally misunderstood you because i don't understand this sentence: "The terms that go into the stress-energy tensor are the four-momenta, the square of which is the invariant rest-mass." unfortunately i don't know what a stress-energy tensor is or what the four momenta are, or the formula that says their square is the invariant rest mass.

 

It means gravity (warping) depends on rest mass, not relativistic mass.

[someguy]

i don't think it implies that at all. it implies that if kinetic energy is defined by being the energy added to an object in order to displace it in space as it travels through time, then you can't call the energy transfer kinetic in every reference frame, like one pegged to the pool ball that makes the other two seem to spontaneously move. i think that if you add kinetic energy to an object the effect is that it's mass, the quantity that it warps sapce-time, increases. from some frames of reference by the definition of kinetic energy this works in others the definition of kinetic energy can't be used since the object in question is pegged to the reference frame and therefore it does not travel through space. however you still transferred energy to it. i would be satisfied with calling it kinetic energy, but if you want to be strict about the definition of kinetic energy as displacement within a reference frame then you can't call it that. i think that it's a limitation on the construction of language. it's not a limitiation of nature.

 

as for your second part if relativistic increase in mass in not an increase in the magnitude of warping of space-time then what is it? i thought this was mass by definition. if it isn't then what is mass? simply potential of momentum? if so then that's weird, i feel that the quantity of warp of space time should be called something different then. it seems odd to me that there are two seperate things sharing the same name, science is finding how things are different and categorising them by naming them and giving them defintions. that means that mass is not interchangeable in mathematical equations and that's untidy because also a way that science can work is to take multiple equations that share the same components and mix them together if you had different kinds of mass you couldn't do this, and that seems to me to go against the way science was designed to be.

[someguy]

oops this is instead of my double post. i couldn't figure out how to delete.

[swansont]

You do have different kinds of mass, but partly that's because of discussions like these. In more advanced physics, generally what is used is invariant, or rest, mass. It's useful because its value does not depend on the reference frame.

 

In other discussions, people use relativistic mass, coming from E = mc². All energy from motion is included in the mass, so this will depend on the reference frame.

 

The problem is that that's not the whole equation.

 

E²=p²c² +m₀²c⁴

 

m₀ is the rest mass. All of the energy from motion is included in the kinetic term. The kinetic term is still different in different frames, but the mass term is not. (When it is said that the photon has no mass, this is the equation that's being referenced.)

 

You can see that E = mc² falls out of that equation if an object is at rest, and then the mass is rest mass.

[someguy]

in that case i have a few questions. how can they know when an object is at rest and how can they measure the mass it is at what they figure to be at rest. also are you saying that light has mass just not rest mass? this doesn't seem possible because then it couldn't travel at the speed of light right? its mass would exponentially increase in relation to velocity. or are you saying that it only doesn't have any motion induced mass and only rest mass. that would be equally strange to me.

 

i know that you need to define a "rest" mass in order to find relativistic masses but i'm not sure if it could be completely invariable and if it was, then couldn't you say you have found the slowest speed possible? i mean if mass increases as velocity increases then every state of an object must be more massive than its rest mass unless it is at rest. but rest compared to what? absolute rest? how can you find the rest mass without going to rest. unless you first have an equation you can use to remove velocity but then how did you get that equation without knowing a rest mass. unless they mean to say earthsync mass instead of rest mass in which case it would not be invariable. and i think this is sort of what they did. they just decided that rest compared to earth was rest so that they could could have a reference where they could compared all objects independently and use the same reference for rest. and if that is the case then part of your rest mass is indeed kinetic not to mention the kinetic movement of the molecules and smaller parts it consists of.

 

but i still don't think any of this challenges the solution to the pool ball solution.

[swansont]

in that case i have a few questions. how can they know when an object is at rest and how can they measure the mass it is at what they figure to be at rest. also are you saying that light has mass just not rest mass? this doesn't seem possible because then it couldn't travel at the speed of light right? its mass would exponentially increase in relation to velocity. or are you saying that it only doesn't have any motion induced mass and only rest mass. that would be equally strange to me.

 

The object is at rest with respect to the observer, or the object is moving at a known speed(s) with respect to the observer, and the kinetic term is/are removed. Protons and electrons, for example, are measured in Penning traps, where you can measure the cyclotron motion, which is mass-dependent.

 

Photons have no rest mass, which means they move at c. If you want to define a relativistic mass, then they have it, but as they always travel at c, it is not speed dependent. It is dependent on the frequency (and thus energy) of the photon. It would represent the maximum amount of rest mass a photon could create.

 

i know that you need to define a "rest" mass in order to find relativistic masses but i'm not sure if it could be completely invariable and if it was, then couldn't you say you have found the slowest speed possible? i mean if mass increases as velocity increases then every state of an object must be more massive than its rest mass unless it is at rest. but rest compared to what? absolute rest? how can you find the rest mass without going to rest. unless you first have an equation you can use to remove velocity but then how did you get that equation without knowing a rest mass. unless they mean to say earthsync mass instead of rest mass in which case it would not be invariable. and i think this is sort of what they did. they just decided that rest compared to earth was rest so that they could could have a reference where they could compared all objects independently and use the same reference for rest. and if that is the case then part of your rest mass is indeed kinetic not to mention the kinetic movement of the molecules and smaller parts it consists of.

 

but i still don't think any of this challenges the solution to the pool ball solution.

 

At rest is always with respect to a particular frame; there is no absolute rest.

 

No, this really has little to do with the pool ball. That solution has been given. The frame in which momentum isn't conserved isn't an inertial frame, so there's no valid reason to expect momentum to be conserved.

[lucaspa]

I agree that for a theory to be accepted by everyone it needs to be falsifiable and at some point tested. but i have never personally tested anything of the theory of relativity and i didn't believe it until i was logically convinced of it even though i knew it had been tested.

 

You are confusing your acceptance of the theory with whether the theory is accurate. Whether YOU believe the theory has nothing to do with whether the theory is valid or invalid.

 

What you have confessed to is that you don't do science. You are saying that the universe must conform to someguy's idea of logic.

 

the problem is some flaws in arguments are really hard to find and the only way to test them is by empirical testing.

 

ALL hypotheses/theories must be tested. A theory can have perfect logic, but if the data is against it, it is wrong.

 

but you could easily, well not easily, but you could convince me of something without my testing it, and in fact if you can't do this then to me it's a little sketchy.

 

Another confession you aren't doing science. Sorry, but I don't care if I can convince YOU. All I care about is whether the theory is tested and accurate. Whether "someguy" or "galaxyblur" accept it is irrelevant. I know that makes you sound unimportant, but you are unimportant compared to the accuracy of the idea.

 

that's why i don't really like string theory because everybody can tell me what it is, nobody can tell me why, except maybe with some math but math alone, in my opinion is only as good as it is related to reality,

 

And guess what you are doing here? Testing the theory. That's the first test of a theory: it must be consistent with known data. So, if the math portrays a universe that doesn't match the one we already see, then that is a test of the theory. And a test the theory fails.

 

if you mess up the relationship with reality it's just as good as a flawed argument,

 

Better. Because now you've got a failed test of the theory.

 

I think, someguy, that you may actually do testing and depend upon it. You just don't realize that you do.

 

if you properly pegged it to reality you can make discoveries with math and not with any empirical tests or observations and that would be, in some cases, sufficient for me, but the thing is usually math gets tailored to properly represent observations and tests therefore a prediction of some untested thing could be wrong

 

When you say "math gets tailored to properly represent observations", that is because those observations are the initial tests. So the theory (math) is modified in the face of data.

 

Remember, observations we have already made are still "direct experience of the universe".

 

Now, the way you distinguish between competing theories that both cover known observations is to look at knowledge we should find (predictions) IF the theory is true. Then you do experiments to test for them.

 

Both Special Relativity and Newtonian gravity covered known observations. BUT, Special Relativity predicted that light would bend in a sufficiently strong gravitational field. Newtonian gravity predicted light would continue in a straight line. So, in 1919 Eddington and others looked for the position of stars during an eclipse. They were displaced from light traveling in a straight line. Special Relativity supported, Newtonian gravity falsified.