Explain Mass.

[InfiniteNow]

The observation of mass can be independent of density. For example, an observation of a satellite in a perfectly circular orbit a primary body reveals the primary’s effective mass, but little about its density. A body of uniform density is indistinguishable using this kind of observation from one with all of its mass concentrated in a dense shell, or a dense core.

Does this still hold true if you know it's size? My question meaning, if you have a satellite in a perfectly circular orbit around a primary body, let's say the object (satellite) is of size X, couldn't you tell that this object is denser than an object occupying the same orbit, influencing the primary body in the same way, but let's say this other satellite is of size 10X?

 

Two objects, same influence, different size... wouldn't that reveal information about each object's density, if nothing else, at least relative to each other?

[Little Bang]

CraigD, would you suspect that Fermi- Dirac statistics break down in a black hole?

[CraigD]

… if you have a satellite in a perfectly circular orbit around a primary body, let's say the object (satellite) is of size X, couldn't you tell that this object is denser than an object occupying the same orbit, influencing the primary body in the same way, but let's say this other satellite is of size 10X?

 

Two objects, same influence, different size... wouldn't that reveal information about each object's density, if nothing else, at least relative to each other?

The orbital period of a small body (a satellite) around a much larger one (its primary) is nearly independent of its mass. So, you can estimate the mass of the primary, but not of the satellite, from observing its satellites.

 

In principle, you can measure the mass of a satellite by the “wobble” of its primary, but this is more difficult than measuring orbital radius and period. If moons are in different nearby orbits, you can measure their interaction to learn something of their relative masses, but this is also more difficult.

[CraigD]

CraigD, would you suspect that Fermi- Dirac statistics break down in a black hole?

I don’t have any confidence speculating either that they do, or don’t break down in a black hole.

 

The observed data on all of the black hole candidate I know of can be explained by either degenerate matter, which quantum particle physics can explain, or infinitely dense singularities, which a General Relativity-based model of gravity implies, but QPP can’t explain.

 

Until a better understanding of gravity exists, I don’t believe anybody can have much well-founded confidence in any explanation of what goes in black holes. Is gravity due to a fundamental particle (the graviton)? Is it due to geometry? Science has yet to compellingly answer these questions.

[Farsight]

I think the idea of "gravitons" has very little that's compelling about it.

[IDMclean]

Well, if Gravitions exist then I imagine they would be macroscopic particles. I mean, who says a particle has to be small?

[Farsight]

That takes us halfway there, KickAss. And when they aren't particles either we're home and dry.

 

:hihi:

[Little Bang]

I find it curious that the observed mass of a particle is dependent on it's movement with respect to the observer.

[Tim_Lou]

i've read some wikipedia articles about masses... it says that mass is defined such that momentum is conserved.

 

http://en.wikibooks.org/wiki/Special_Relativity:_Dynamics

i found an excellent derivation of relativistic mass... before reading it, you should understand the general lorenz transformation in 3d.

 

(the symbols ARE confusing... it took me quite a while to go through the whole thing)

[Little Bang]

I'm sure everyone has heard the story of the three blind men each giving a description of a different part of an elephant. Let's have a play like king that was raised in an environment were he never saw any animals not even an insect. The kings job is to draw a picture of an elephant. It should be obvious that the king has an enormously difficult task. We find ourselves in exactly the same position as our play like king. We are trying to take all the phenomena that matter exhibits and turn it into a coherent picture of something we have never seen let alone imagine. To me one of the most difficult aspects of mass is that it changes it's values just from the act of observing it. We need to understand our role as observers in the phenomena that mass displays.

[arkain101]

*rubs chin*

 

Some good reading lately in here...

 

I think mass can be defined as a relationship. A product of other relationships, and not an actual entity.

 

All masses can be said to be an operation that is a bend of space-time. However they do not need to be an actual thing. As gravity appears to be a force, but it is arguably not a force in the same sense as typical forces.

[HIENVN]

I am curious to hear some people's best description of what exactly seems to give 'mass' its mass. What or how is it that mass has inertia. What reason exactly does it want to be as it is and fire back an equal force of anything that forces upon it?

No simple obvious answers like, It has mass/inertia because its heavy. In my humble opinion it seems mysterious where mass comes from and how inertia exists.

Mass is often defined as the amount of matter in an object. However, scientists usually define mass as a measure of inertia, which is a property of all matter. Inertia is the tendency of a motionless object to remain motionless and of a moving object to continue moving at a constant speed and in the same direction. Inertia is a property of all matter; the English scientist Sir Isaac Newton first described inertia. He introduced the idea in his first law of motion, which was published in 1687 (World Book 2001 Edition).

Although scientists have tried to explain mass or matter by the means of inertia, but their efficiency should be considered as an uncompleted explanation because the inertia that they used is not suitable for an explanation.

The inertia that Newton first described should be considered as a type of “Moving Inertia,” which is using for a description better than an explanation. In order to explain mass or matter, we should use a type of “Energy Inertia” that is initial stated as below:

“When an object absorb/emit energy from/to the air, meanwhile this object emitted/absorbed its energy to/from the space of universe.”

[maxc]

Find something that's motionless? Of coarse it not observable by any normal equipment. Or is it?

[Little Bang]

Find something motionless with respect to what? There is no point in the universe that is absolute.

[arkain101]

Find something motionless with respect to what? There is no point in the universe that is absolute.

 

Which always confuses the heck out of me for understanding how you can consider something moving near the speed of light where it might be exceeding it according to something else..

[Qfwfq]

You might be less confused by it if you work out the Lorentz transformations properly. If v < c for one observer, it is so for all. It's a direct consequence of the transforms being those such that c is equal for all.

[arkain101]

What I mean is, when there is no absolute, there is no way to decifer which object is containing all the motion.

 

One observer might measure an object traveling .99C , and another observer that is moving but always considered itself at rest, might measure it to be covering distance faster than .99C, and maybe beyond "C" . I've seen, heard, and read many versions of how to explain this. Some claim an absolute and others dont. Its not about do I understand it, its about, which way is the right way to eliminate all paradox's and errors(?).