Mass and energy question

[Brett Nortje]

Isn't it true that if something does not have mass it does not have energy? I always thought so, so let me explain...

 

If the 'thing' doesn't have mass, it will not be able to react, as mass is in effect stored energy. or what?

[swansont]

No. Having mass implies having energy, but the reverse is not true. Photons have energy, but they have no mass.

 

E² = m²c⁴ + p²c²

[Brett Nortje]

No. Having mass implies having energy, but the reverse is not true. Photons have energy, but they have no mass.

 

E² = m²c⁴ + p²c²

 

How do you know they have no mass? if they had no mass, they could pass right through everything - like they do - but, to have properties indicates some carbon parts, and that means they have to have a mass, as without a mass, they will not react with anything as they encounter it?

[ajb]

How do you know they have no mass?

For theoretical reasons we think that photons have no mass. Experimentally there are upper bounds on the photon mass. These bounds are very light meaning that massless photons are consistent with what we observe.

if they had no mass, they could pass right through everything - like they do - but, to have properties indicates some carbon parts, and that means they have to have a mass, as without a mass, they will not react with anything as they encounter it?

We do not need mass for particles to interact. Edited June 12, 2013 by ajb

[daniton]

 

How do you know they have no mass? if they had no mass, they could pass right through everything - like they do - but, to have properties indicates some carbon parts, and that means they have to have a mass, as without a mass, they will not react with anything as they encounter it?

Mass is a particular property of matter like charge you could measure it study it determine it. But energy is not something like that it even doesn't have a precise definition, you could quantify it depending on your definition. As far as I know energy makes sense when you study the transformation rather than as it is.

[Brett Nortje]

For theoretical reasons we think that photons have no mass. Experimentally there are upper bounds on the photon mass. These bounds are very light meaning that massless photons are consistent with what we observe.We do not need mass for particles to interact.

 

Mass is a particular property of matter like charge you could measure it study it determine it. But energy is not something like that it even doesn't have a precise definition, you could quantify it depending on your definition. As far as I know energy makes sense when you study the transformation rather than as it is.

 

Well, then, do quarks have mass? being the parts of atoms, and particles are somewhere further up I think, how could quarks have mass, and things they make up don't? please answer me that and I am done, thanks.

[ajb]

Well, then, do quarks have mass?

Quarks have mass.

 

You can look up the current accepted values.

 

The two families of particles that are comprised of quarks have mass. Note that the so called hadrons are not fundamental. The photon is fundamental and not made of quarks.

Edited June 12, 2013 by ajb

[daniton]

 

how could quarks have mass, and things they make up don't?

Name particle that made up of quark but doesn't have mass?

see Standard Model

[Delta1212]

 

 

Well, then, do quarks have mass? being the parts of atoms, and particles are somewhere further up I think, how could quarks have mass, and things they make up don't? please answer me that and I am done, thanks.

Atoms are made up of particles. Fundamental particles are not made of atoms. Photons are not made up of atoms and do not contain quarks.

[studiot]

Energy has mass.

 

You guys might like to read Frank Wilczek on the subject.

 

http://web.mit.edu/physics/news/physicsatmit/physicsatmit_03_wilczek_originofmass.pdf

 

or get his book, "The lightness of being".

[Brett Nortje]

Atoms are made up of particles. Fundamental particles are not made of atoms. Photons are not made up of atoms and do not contain quarks.

 

that's the best explanation I have heard... thanks.

[swansont]

Energy has mass.

 

You guys might like to read Frank Wilczek on the subject.

 

http://web.mit.edu/physics/news/physicsatmit/physicsatmit_03_wilczek_originofmass.pdf

 

or get his book, "The lightness of being".

 

He's cheating. Anyone is familiar with Einstein's paper should be able to spot the multiple instances of bait-and-switch. Anyway, at no point does he claim a photon has mass.

[imatfaal]

!

Moderator Note

 

Post regarding four dimensional space as "the cube" was split off as a hijack to the trash can.

 

Roger.

Do not hijack mainstream threads with your speculative ideas.

 

Do not respond to this modnote in the thread.

 

[MigL]

Ahh, but photons have zero REST mass, and since they can never be at rest, we could say that massless particles at rest have no energy since they would no longer exist.