What is Mass? Exploring Its Origins

[CarlosLara]

Good afternoon. I am wondering what exactly is mass. Some say, quite inaccurately, that it is a measure of how much "stuff" an object has (what do they mean by "stuff"?). Others say that it's a quantity that means resistance to acceleration. What is mass and where does the mass of particles come from? I read that it arises from spontaneous symmetry breaking of the electroweak force through interaction with 2 Higgs fields. Could anyone explain this in a very straightforward way?

Thank you in advance.

 

[ZxcvbnM2000]

Mass is the amount of matter that is confined within a shape.

i.e for a gas m = n*M

 

[tiny-tim]

Hi CarlosLara!

Asking "what is …" is ambiguous.

It can mean either "How come … ?" or "So what … ?"​

The "so what" of mass is that it is resistance to acceleration (m = F/a).

The "how come" of mass is unknown, but maybe it comes from the Higgs field …

compare it with charge: some particles do not interact with the electromagnetic field, and so we say they have zero charge: others do interact via a "coupling constant" which we call the charge …

similarly, loosely speaking, maybe the photon does not interact with the Higgs field and so has no mass, while other particles do interact, and so passing through the Higgs field slows them down, and we call the "coupling constant" the mass.

 

[cosmik debris]

Mass is a property of matter. "Stuff" usually means matter. Mass can be measured in different ways. One is to see how much it resists acceleration, another is to see how it accelerates other "stuff" towards it. Ultimately is boils down to comparing a mass with a known standard mass that lives in Paris.

 

[camilus]

Mass is condensed energy.

 

[Fightfish]

Mass is condensed energy.

Seconded.
To add on: that curves space-time.

 

[Drakkith]

Mass is condensed energy.

Seconded.
To add on: that curves space-time.

Are you certain of this? Consider that you will never find energy "by itself", but only as a property of another particle or a field with respect to something else.

Also, please tell me how you can condense something that's definition is "the ability to perform work".

 

[cragar]

This is probably not technically right but how about the ability to resist change in
velocity.

 

[harrylin]

Mass is condensed energy.

Quite so: I would say that mass is a property of bundled or condensed energy.

Formerly mass was defined as "amount of matter", but if taken literally then that only works well in approximation. For example, if you put several atoms together in a molecule, technically you still have the same amount of matter but the molecule has slightly less mass than the separate atoms.
- http://www.phys.unsw.edu.au/einsteinlight/jw/module5_binding.htm

 

[Fightfish]

I meant to agree with the notion of mass being a form of "trapped" or "localised" energy. That's how I tend to see it; though to me it is also sometimes a proportionality constant of sorts in classical mechanics.

 

[Whovian]

If you're asking what it is by trying to figure out what causes it, I think that's still an open question, and one of the theories is the Higgs Boson. But that's all speculation.

 

[cragar]

light could be thought of condensed energy and it has no mass.

 

[Whovian]

light could be thought of condensed energy and it has no mass.

The key word here is rest mass. Light has mass when moving at speed c, it just has no rest mass. Anyways, anything with energy must necessarily have mass.

 

[cragar]

The key word here is rest mass. Light has mass when moving at speed c, it just has no rest mass. Anyways, anything with energy must necessarily have mass.

ok very good. Ya I forgot about the difference between relativistic mass and rest mass and like effective mass .

 

[Drakkith]

The key word here is rest mass. Light has mass when moving at speed c, it just has no rest mass. Anyways, anything with energy must necessarily have mass.

It's better to just drop "relativistic mass" and use momentum instead. Energy contributes to gravity so everything still works fine. Photons have no mass, ever!

 

[kevinsetiono]

mass is not constant , it depends on gravity . W = M.g so , i want to ask , if we are on the vacuum room , is our mass becoming zero ?

 

[kevinsetiono]

mass is not constant , it depends on gravity . W = M.g so , i want to ask , if we are on the vacuum room , is our mass becoming zero ?

 

[Whovian]

mass is not constant , it depends on gravity . W = M.g so , i want to ask , if we are on the vacuum room , is our mass becoming zero ?

First, you're talking about weight, not mass, here. Assuming you haven't done any Special Relativity, we'll assume Newtonian Mechanics here.

Mass is constant in Newtonian Mechanics. Weight, $\displaystyle W=m\cdot g$, where $g$ is acceleration due to gravity. If we're in a room with no air in it (assuming we could survive this), our weight is not zero. Gravity can still affect people through a vacuum. Example: Astronauts on the Moon.

 

[kevinsetiono]

how about if we are on room with no gravity ?

 

[Drakkith]

how about if we are on room with no gravity ?

If you have no gravity then you have no weight, but you most definitely still have mass. It's still harder to push a 10 kg block than a 1 kg block while weightless.

 

[kevinsetiono]

if mass is energy and gravity also package of energy called graviton , i just make a conclusion if mass have positive charge and graviton have negative charge . if we make conclusion like that , so electron can not affected by gravity , isn't it ?

 

[Drakkith]

if mass is energy and gravity also package of energy called graviton , i just make a conclusion if mass have positive charge and graviton have negative charge . if we make conclusion like that , so electron can not affected by gravity , isn't it ?

I have no idea why you are making those conclusions. They are 100% incorrect. Mass isn't energy, gravitons have never been observed, and mass having a + charge with gravitons having a - charge doesn't work or make any sense with how the universe works.

 

[kevinsetiono]

i am sorry for my conclusion .
so , if not energy what is the most specified thing to describe what is mass ?
is mass depends on the speed of light ?
i just read about one formula
m' = m/ ((1- (v/c)^2)) ^0.5

 

[Drakkith]

i am sorry for my conclusion .
so , if not energy what is the most specified thing to describe what is mass ?

There is no easy definition as to what mass is. See here: http://en.wikipedia.org/wiki/Mass

is mass depends on the speed of light ?

No, our unit of measurement for mass, the kilogram, is set by us. The speed of light has nothing to do with it.

i just read about one formula
m' = m/ ((1- (v/c)^2)) ^0.5

I'm not quite sure what that formula is for. Where did you find it?

 

[kevinsetiono]

i forget where i found that formula , i will find it later, i just remember it just explained if mass depends by c , if mass move with speed same with c , we can conclude if that thing has infinite mass . that is paradox of quantum physics

 

[Whovian]

I'm not quite sure what that formula is for. Where did you find it?

I'm pretty certain that's the Relativistic Formula for mass.

 

[Drakkith]

i forget where i found that formula , i will find it later, i just remember it just explained if mass depends by c , if mass move with speed same with c , we can conclude if that thing has infinite mass . that is paradox of quantum physics

I think what you are talking about is the energy required to accelerate an object to a speed. The velocity of an object can never reach c because it would take an infinite amount of energy to accelerate it to c. AKA it can't happen. The mass of a moving object does not increase. In it's own frame the object will always have the same mass.

I'm pretty certain that's the Relativistic Formula for mass.

Not sure, I've never seen it before. (Which isn't saying much, I haven't studied physics)

 

[Dead Boss]

That formula is the so-called "relativistic mass" and is no longer used, because it is just equal to $\frac{E}{c^2}$. Mass of an object is the unprimed m in the formula and is invariant. As Drakkith said, the energy increases with speed, not mass.

 

[tiny-tim]

hi kevinsetiono!

if mass is energy and gravity also package of energy called graviton

the gravitational field is not made of gravitons, you might as well say that a magnetic field is made of photons

is mass depends on the speed of light ?
i just read about one formula
m' = m/ ((1- (v/c)^2)) ^0.5

the mass (your " m ", the mass something has when stationary) of a particle has nothing do with c

the "relativistic mass" (your " m' ") is the rest-mass times a factor that depends on v/c

the mass of a particle depends only on how strongly it couples to the higgs field

… if mass depends by c , if mass move with speed same with c , we can conclude if that thing has infinite mass . that is paradox of quantum physics

yes, but that has nothing to do with quantum physics, only with relativity

and there's no paradox, since it can't move with speed c

 

[kevinsetiono]

hello tiny tim

i still don't understand about rest mass, can you give me the referral links ?
is magnetic field made of photon ?

 

[kevinsetiono]

That formula is the so-called "relativistic mass" and is no longer used, because it is just equal to $\frac{E}{c^2}$. Mass of an object is the unprimed m in the formula and is invariant. As Drakkith said, the energy increases with speed, not mass.

will it be the same value between my formula and E / c^2?

 

[tiny-tim]

hello kevinsetiono!

it's easiest to think in terms of the energy, E

for every particle, E/c² is proportional to 1/√(1 - v²/c²), where v is the speed

we call the constant of proportionality the mass, m …

E/c² = m/√(1 - v²/c²)​

we can also write it

E√(1 - v²/c²)/c² = m​

from that we immediately see that, for a photon (for which v = c always), m = 0 …

the mass of a photon is zero​

since m is the value of E/c² when v = 0, we also call m the rest-mass, the energy it has when it's at rest (divided by c²)

(obviously, a photon can't be at rest, so "rest-mass" is a meaningless name for a photon … that's why nowadays we usually prefer to call it "mass" rather than "rest-mass" )

is magnetic field made of photon ?

the magnetic field is part of the electromagnetic field

it isn't "made" of anything, it just "is"

light waves are a special kind of electromagnetic field, in which the electric and magnetic parts are equal and perpendicular

 

[kevinsetiono]

i was count the formula
if the formula m' = m / (( 1-(V /c )^ 2 )) ^ 0,5 have the same state with m= E/ c^2
it will make the final formula m ' = m. E / ((c.v)^2)
i just think if this formula is right , the rest mass is very very small if v=c
one question : i don't know what difference between rest mass ( m' ) and mass ( m)

sorry if wrong :)

 

[Whovian]

There are two kinds of mass: relativistic mass, and rest mass.

Rest mass is the mass an object has at rest.
Relativistic mass is the total mass, affected quite a bit by velocity, also equal to kinetic energy + rest mass (after, of course, converting kinetic energy via E=mc^2 and note that the formula for kinetic energy is no longer mv^2/2)

 

[Dead Boss]

i was count the formula
if the formula m' = m / (( 1-(V /c )^ 2 )) ^ 0,5 have the same state with m= E/ c^2
it will make the final formula m ' = m. E / ((c.v)^2)
i just think if this formula is right , the rest mass is very very small if v=c
one question : i don't know what difference between rest mass ( m' ) and mass ( m)

sorry if wrong :)

It's the other way around.
m is rest mass, or simply mass and it does not change with speed
m' is relativistic mass and it increases with speed

The substitution you should be making is:
m' = E/ c^2 = m / (( 1-(V /c )^ 2 )) ^ 0,5
So: m' = Ec^2/(( 1-(V /c )^ 2 )) ^ 0,5

I should stress that relativistic mass is not a very useful concept and it's not healthy to treat it as the mass of an object.