Electrons: Mass or massless?

[waxy]

in scientific american (maybe american scientist, not sure) it <br />stated that electrons are basic particles that are massless.<br /><br />however, i find several places on the net that descibe<br />them as having mass. one example link is:<br />http://scienceworld.wolfram.com/physics/ElectronMass.html<br /><br />which is it?<br />

 

[harmonicaman]

It's probably just a wave or vibration that manifests some of the properties of mass in special situations. Everything in the universe is related on the subatomic level.<br /><br />When electrons are collided, sometimes a small bit of mass (muon) is produced.

 

[vogon13]

IIRC, mass of the electron is ~511kev.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[waxy]

ohhhhhhh nice. i love fast answers.<br />I remember in the old days when i went to school radiation was<br />alpha, beta, and gamma. now it's electrons, protons, and <br />photons (i think).<br /><br />it's 'probrably' a wave or vibration, perhaps even an ossilation<br />(such as they think occurs to nutrinos from the sun)<br />but how sure are we? i'd like to ponder this some more, <br />by any chance do you have a link to a collision biproduct table?<br /><br />i'd love to see this + that = these<br />(the + being collision, not addation)<br />

 

[thermionic]

<br /> I was taught that electrons were as close to being point-masses as has been observed. But I was taught that point-masses can't exist. Weird stuff...<br /><br />The particle that gets discussed regarding whether it has rest mass or not is the neutrino. Recently it has been established (I think) that it does have a very tiny rest mass. Maybe that's the one you were reading about?

 

[bonzelite]

but please take into account that rest mass expressed in electron volts is not really a mass as you may think. it is not like the weight of a car or truck.<br /><br />electrons, as i have always contended despite disagreements, are not even objects: a rest mass is given for mathematical ease of use in computation --electrons are never at rest. and they are unweighable. <br /><br />an electron is basically a <i>probability</i> in a given field. it's actual coordinate of existence cannot be tracked or located literally, but can only be statistically implied or extrapolated. an electron cannot exist outside of this probability field at rest or as an individual particle. <br /><br />physical science curricula fail to establish this reality to electrons, resorting instead to diagramatic explantions of all atomic particles and states in terms of tenable objects, as planets and stars. but this illustration, intendend to simplify teaching, perpetuates myths about what they are or may otherwise be. <br /><br />

 

[abhinavkumar_iitr05]

Hello!Waxy<br /><br />As far as I know what electron really is a particle & not <br />a wave.The major fact supporting this idea is that we <br />can't accelerate electron to the speed of light.If this can be achieved then only I can consider it a wave.<br /><br />We all know that if any mass achieve the speed of light,then its mass at that speed becomes infinite.Now there is great difference between the behaviour of photon & electron.We know that photon has the speed of light & its rest mass is zero though it has momentum at a speed of light given by Planck const./wave length.But since we can't accelerate electron at that <br />speed so it has some rest mass which has even been <br />calculated & comes out to be roughly equal to 511Kev.<br /><br />Now its up to u to beleive whether electron is to be <br />consider as a wave or as a particle.

 

[harmonicaman]

<b>Abhina -</b><br /><br /><i>"As far as I know the electron really is a particle & not <br />a wave... The major fact supporting this idea is that we <br />can't accelerate electron to the speed of light."</i><br /><br />When I stated that the electron was probably a wave rather than a particle, this was a vague reference to String Theory (Brian Green's <u>The Elegant Universe</u>) which postulates that on a sub-atomic level, everything in the universe is basically orchestrated into a system of multidimensional vibrating strings. <br /> <br />I used to work at the Cornell University Wilson Synchrotron (now semi-retired) and we accelerated electrons and (their counterparts, the positrons) to 99.9999995% the speed of light all day long¹ and then smashed them into each other to see what would happen... <br /><br />The accelerated particles are highly energized at these relativistic velocities, thus the study of jazzed particles is called High Energy Physics.<br /><br />1. The Wilson Synchrotron in Ithaca, NY is scheduled to go back on line starting 2/1/06 and they would be happy to give you a tour of the facilities if you ask!

 

[waxy]

AH! that explains why i've seen it explained as both - <br />it was in a string theory article that i saw it explained as <br />massless. It didn't occur to me that it's only massless by<br />that theory, which explins why i've seen it explained as both.<br /><br />Thanks for the help guys. <br />BTW - where's a good link to a collision table?<br />eg: THIS collide THAT = THESE<br />i've been searching but i haven't had much luck.<br />

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>an electron is basically a probability in a given field. it's actual coordinate of existence cannot be tracked or located literally, but can only be statistically implied or extrapolated. an electron cannot exist outside of this probability field at rest or as an individual particle.<p><hr /></p></p></blockquote><br /><br />Actually, you can determine an electron's actual "coordinate of existence" -- but if you do, you won't be able to tell its velocity. Conversely, if you measure it's velocity, you won't be able to tell it's position. This is the Heisenberg Uncertainty Principle -- no method to measure the location *and* velocity of an electron exists which will not influence one or the other to the point that it is impossible to determine. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[meteo]

Yes, electrons have mass as was stated 0.511 MeV or 9.11 x 10^-31 kg. Now to the wave or particle question. Actually an electron is both a wave and a particle. This was first proposed by de Broglie.<br /><br />http://en.wikipedia.org/wiki/Wave-particle_duality<br /><br />The wavelength of an electron or any particle for that matter is equal to h/p. h is plank's constant and p is the momentum. You've heard of light diffraction right? <br /><br />http://en.wikipedia.org/wiki/Diffraction_of_light<br /><br />Well you can have diffraction of electrons and other particles too. This was the first evidence for the wave properties of matter.