Why does mass curve space-time?

[Mr Skeptic]

We don't know. It's not a question that needs to be answered for current science to progress.

 

What would be falsified if we have a mechanism? Would spacetime no longer be curved? Would any experimental results change?

 

Well, it would be nice to be able to calculate G rather than to measure it.

[lemur]

We don't know. It's not a question that needs to be answered for current science to progress.

 

What would be falsified if we have a mechanism? Would spacetime no longer be curved? Would any experimental results change?

 

It's not so much that results would change, imo, it's that people would get a clearer view of the relationship between spacetime and point-particles, which would aid further theorization.

 

(Faulty) assumptions can result in bias that branches out into multiple applications of a base theory.

Edited December 16, 2010 by lemur

[swansont]

It's not so much that results would change, imo, it's that people would get a clearer view of the relationship between spacetime and point-particles, which would aid further theorization.

 

(Faulty) assumptions can result in bias that branches out into multiple applications of a base theory.

 

Not knowing (or not knowing and not caring) isn't a faulty assumption, or any assumption of any kind. Knowing might aid in further theorization, but it's not necessary for the existing theories. It might become necessary if there are (new) observations which do not fit the existing theories, but that's always been the case in science. But without the ability for experimental testing which could confirm or falsify, it's not a scientific topic.

 

Well, it would be nice to be able to calculate G rather than to measure it.

 

There are a number of fundamental constants for which this is true.

[Incendia]

Just answer the question...If anything it will strengthen and clarify the current view physics has of the universe which can only be good. It could stop some physicists following red-herrings etc. If more it could give you a reason to re-think your current theories as the why could conflict with your ideas of what and how or could spawn a lot of new predictions and open up new theory opportunities.

We can't experimentally test many theories...it can be falsified by other facts and theories...it can be confirmed by sounding true and matching observation.

You may think this is a waste of time, Swansont, but it isn't.

[swansont]

 

You may think this is a waste of time, Swansont, but it isn't.

 

I don't see where I said that it was.

[Moontanman]

The point is that one cannot distinguish (in a small enough region) between gravitational free fall and acceleration. Applying this to a light beam suggests that space-time is curved.

 

 

It seems counter intuitive to me that acceleration cannot be distinguished from gravity, I can think of at least one case where acceleration can be differentiated from gravity with no access to the outside world.

[Incendia]

If you didn't think finding the answer was a waste of time you wouldn't say it is unnecessary to do physics.

 

Like I said...it can disprove your what/how. Super simple Eg:

 

1. What: A cake, How: Cooking.

2.Why: I'm hungry and want to make something like chicken.

3. point 1 is now obviously wrong.

4. What: Chicken, How: Cooking.

 

Less simple eg:

1. Mass curves space-time creating gravity. [What]

2. [insert explanation of the new shape of space-time after being curves by mass.] [how]

3. Why is discovered: Mass does not curve space-time. Space and time are dimensions but time is not connected to space. Time moves independently to space and time is pulled on by gravity whilst space is not. This cause time to be in concentration around things with mass and things with mass have gravity. Space is not curved. /Random why which is probably wrong but is just there to show that a why can fly in the face of everything you know such as a space-time continuum composed of space and time being one./ <Though if it could be true feel free to discuss...]

[D H]

Just answer the question...

First a request about your posting style: Please stop using italics. It makes what you write hard to read. Think of it this way: Try reading one of those license agreements on a game or piece of software you have purchased. The key legal portions are invariably written in a tiny font, or in bold, or in all caps, or in italics, or some combination of the above. Never, ever in plain text. Corporate lawyers do not do this so we can see that what they wrote is very important for us to read and understand. To the contrary: They do this so that we cannot read or comprehend it. Study after study has shown that such text is hard to read and even harder to comprehend: Exactly what lawyers want when they need to hide something in plain sight.

 

So, rant off.

 

 

Your question has been answered, many times and in many ways: We don't know, and most physicists don't care that we don't know. Do I need to put that in a big bold font? Let's take it a step further. Suppose some future bright physicist did come up with an answer to your question. It almost certainly would not be "the answer". It would instead push the mystery a little deeper. At least this would the fervent hope of all theoretical physicists still working in the arena of theoretical physics.

 

That said, some theoretical physicists are working on answering these deep questions. Google the phrase "beyond the standard model". So far, no joy, but they are working on it.

Edited December 16, 2010 by D H

[lemur]

Not knowing (or not knowing and not caring) isn't a faulty assumption, or any assumption of any kind. Knowing might aid in further theorization, but it's not necessary for the existing theories. It might become necessary if there are (new) observations which do not fit the existing theories, but that's always been the case in science. But without the ability for experimental testing which could confirm or falsify, it's not a scientific topic.

So if you theorize that space consists of particles, it is a scientific topic but if I say that you'll always continue to have the problem of explaining what is in between the particles as "space," then you say it's not a scientific topic? I agree with you that to claim that space exists purely as the discrepancy between (loose) gravitational field-force and other "tighter" forces, that should somehow be observable or testable. I have been trying to think of ways to do this. So far I've only come up with trying to find some region of space where gravitation is absent. I don't see how this could be even theoretically possible unless gravitation would have a lower limit at which it became non-existent. How is gravitation measured in space, actually? Is it just a question of measuring the speed of objects orbiting each other? Don't you then have to know their mass? How do you know a planet or star's mass except in reference to its celestial motion relative to other bodies? It seems like all these measurements are interdependent. Which can be measured independently of the others and how? Mass? Distance? Speed? Gravitation?

 

The only thing I can think of is that you can measure the speed of a falling object at sea level. Then you can measure the circumference of the Earth (by surface maps?). Then how do you get the mass of the Earth except by assuming Newton's inverse square formula to be true? I guess I should go google how this law was/is tested in the first place.

Edited December 16, 2010 by lemur

[D H]

So if you theorize that space consists of particles, it is a scientific topic but if I say that you'll always continue to have the problem of explaining what is in between the particles as "space," then you say it's not a scientific topic?

No.

 

A new theory in physics has to subsume what we already know. The existing physics is backed up by a lot of experimental evidence.

 

A new theory in physics has to explain something new. Why switch to some new theory if it doesn't have anything new to say?

 

A new theory in physics has to be expressed in mathematics. While we try not to get overly nerdy and delve into math when we talk to lay people, but amongst ourselves, we have no such constraints.

 

A new theory has to be well-justified. In the example at hand, what motivates for this claim that space consists of particles?

 

A new theory has to be elegant and simple. A good example is Lorentz Ether Theory. LET is mathematically indistinguishable from special relativity. Yet no legitimate physicist espouses LET. LET only lives on in the minds of cranks. LET has some ugly ad hoc axioms. In comparison, special relativity is a simple elegant theory.

 

 

A new theory has to be testable, from top to bottom. LET was not testable. Just the opposite. It postulated an absolute reference frame but said that there was no way to detect this frame. That alone makes LET non-scientific. Physicists are the ultimate Missourans (Missouri nickname is the "Show Me" state). The basis for a scientific theory has to be testable.

 

 

[lemur]

A new theory has to be well-justified. In the example at hand, what motivates for this claim that space consists of particles?

I think I've gotten this thread mixed up with another one where that issue of space consisting of particles came up. It's not mine. I was arguing against it. After reviewing this thread, it seems that I was actually trying to make the point that gravity can be viewed as space-time curvature itself instead of as a cause for spacetime curving. I think this is where the issue of whether it would actually matter one way or the other came up, which is your point.

 

To me, if science regards space(time) as a fabric or container separate from its contents, it facilitates an empirical approach to "the universe" as if it was a single unified entity/container filled with contents. I think this is an obfuscation of the empiricist logic that what is observable is all that there is. I don't think science should assume a container for observables unless that container is itself observable. This is why it is important, imo, to ask what space(time) actually is and whether it exists as a thing in the same sense as matter-energy exist because they are empirically observable as non-absent entities.

Edited December 17, 2010 by lemur

[swansont]

If you didn't think finding the answer was a waste of time you wouldn't say it is unnecessary to do physics.

 

It is unnecessary in order to do physics. D H did an excellent job of explaining this. But not everyone is a physicist. If you want to think about it, go right ahead.

[D H]

One important thing has been left unsaid in this discussion. There is nothing wrong in science with saying "we don't know (yet)". At times that is the scientific answer. Trying to go beyond that can take one from the realm of science to non-science.

[lemur]

One important thing has been left unsaid in this discussion. There is nothing wrong in science with saying "we don't know (yet)". At times that is the scientific answer. Trying to go beyond that can take one from the realm of science to non-science.

Science is not a region to inhabit or "go beyond." It is a set of ideas about how to approach research. There's nothing unscientific about asking a question and then subjecting it to critical theorizing about what the empirical observables are, how related claims could be tested and/or falsified, etc. Science is concerned with moving research questions from pure philosophy to critical empiricism. Yes, we want to think about how and why but then we want to check our theories against things we can observe. I hope this doesn't oversimplify too much.

[lemur]

I think you could approach this question by looking at the relationship between the various force-fields present in a given particle, no? An atom has mass due to the protons and neutrons mainly, right? Then there is extra mass added by electrons and weak nuclear force, which seem more like energy-of-motion effects on mass than passive mass (I suspect that no mass is ultimately passive but I don't understand enough about quantum particles to get into that). So you have the strong force of the protons and neutrons attracting each other in the nucleus, right? And the electrostatic force of the electrons and the protons cause the electrons to buffer the atom against other atoms. I think that even the photons sometimes emitted by the electrons generate some gravity, so generally gravitation seems to be some kind of residual force left over from the interactions among the other forces. Is this possible?

 

If so, I would expect a relationship between the cause of mass (i.e. inertia of elementary particles and their configurations) and the effect of gravity (i.e. attractive force among particles with mass). Could the gravity be a separate field from the others or could it be a result of interactions between the other types of fields?

[D H]

That approach doesn't work even for quantum mechanics. It doesn't even come close to working for gravity.

 

People have tried numerous techniques. Attempts to go "beyond the standard model" (google that phrase) don't quite pan out, so far. And the math is beyond intense.

[pioneer]

The easiest way to explain it, is by using the assumption that C is the ground state of the universe. Mass, by being less than C will set a potential with C, with the action of gravity reflecting one means to lower the potential with C. Mass can not directly go to C; spontaneously go poof!, so it needs to use other means to reach C.

 

Say the entire universe was at C. Time and space don't mean anything, since there is only a point-instant. To create finite time and space, we need to break away from C, with the further from C we go. the more time and space can expand. Mass has this property of being below C and part of extended time and space.

 

Mass can't back track, since it would take infinite energy to return to the C reference. Instead it needs to move forward using other means to lower the potential with C, such as trying to cause time and space to return to the point-instant reference of C. The black hole is one resolution.

Edited December 17, 2010 by pioneer

[D H]

I told you guys you would get a crackpot answer.

[lemur]

The easiest way to explain it, is by using the assumption that C is the ground state of the universe. Mass, by being less than C will set a potential with C, with the action of gravity reflecting one means to lower the potential with C. Mass can not directly go to C; spontaneously go poof!, so it needs to use other means to reach C.

 

Say the entire universe was at C. Time and space don't mean anything, since there is only a point-instant. To create finite time and space, we need to break away from C, with the further from C we go. the more time and space can expand. Mass has this property of being below C and part of extended time and space.

 

Mass can't back track, since it would take infinite energy to return to the C reference. Instead it needs to move forward using other means to lower the potential with C, such as trying to cause time and space to return to the point-instant reference of C. The black hole is one resolution.

So are you saying that energy (EM radiation) is attracted to itself, which is the basis of gravity? Thus when energy gets separated into distinct particles, it has a tendency toward radiation and this tendency is what causes the particles to be attracted to each other? There is some elegance/simplicity in this.

[pioneer]

Have you ever tried to use a C reference as the ground state?

Edited December 17, 2010 by pioneer

[lemur]

I told you guys you would get a crackpot answer.

By "crackpot" do you mean deviation from familiar physics or are you actually criticizing the content of the post?

[D H]

In this case, it is meaningless drivel, and I suspect intentionally meaningless drivel posted to generate a response. An attempt at humor.

[lemur]

In this case, it is meaningless drivel, and I suspect intentionally meaningless drivel posted to generate a response. An attempt at humor.

Did you read my response? Did I not provide some further indication about what was meaningful about it? Here's what I sincerely don't understand: Why is it that someone with presumedly more experience and knowledge with physics like you can get absolutely nothing out of a post like that while I can see relevance in it at the general level of how matter and energy are related? Is it because you aren't capable of thinking at that general a level or because there's something about deep understanding of physics that causes one to become fundamentally blind to very basic generalizations about the relationships between fundamental aspects of physics?

 

 

 

[michel123456]

IMHO you must follow a sequence: first find "how", then say "that's the reason why ..."

 

If you go directly to "why" without knowing "how", you are on the wrong path.

[swansont]

Science is not a region to inhabit or "go beyond." It is a set of ideas about how to approach research. There's nothing unscientific about asking a question and then subjecting it to critical theorizing about what the empirical observables are, how related claims could be tested and/or falsified, etc. Science is concerned with moving research questions from pure philosophy to critical empiricism. Yes, we want to think about how and why but then we want to check our theories against things we can observe. I hope this doesn't oversimplify too much.

 

And the reason why mass curves space is something that we can't check against observation. It's possible this would come into play if there were different "kinds" of mass, but the equivalence principle/local position invariance would have to fail, and those are confirmed to hold at a reasonable level of precision.

 

!

Moderator Note

Some posts have been moved over from a similar thread (which has been closed). Sorry for any confusion the additional posts might cause, but it's all on the same topic.

 

 

Did you read my response? Did I not provide some further indication about what was meaningful about it? Here's what I sincerely don't understand: Why is it that someone with presumedly more experience and knowledge with physics like you can get absolutely nothing out of a post like that while I can see relevance in it at the general level of how matter and energy are related? Is it because you aren't capable of thinking at that general a level or because there's something about deep understanding of physics that causes one to become fundamentally blind to very basic generalizations about the relationships between fundamental aspects of physics?

 

If you are referring to your response to pioneer, your "basic generalization" is basically word salad. It has no real physics meaning to it. It's not surprising, because the post to which you were responding was nonsense. Saying "energy gets separated into distinct particles" is meaningless, since energy is not a substance. I don't know what "tendency toward radiation" is supposed to mean. There's a reason physicists define terms and use math to describe phenomena. It cuts down on the twaddle and multiple interpretations of language. Analogies and descriptions may facilitate knowledge (e.g. thinking about entropy as order/disorder) but all analogies fail at some point, and it causes problems when you try and push them too far.