# What is a classical relativistic particle?

Discussion in 'Physics & Math' started by Amadeusboy, Nov 8, 2008.

1. ### AmadeusboyRegistered Member

Messages:
22
What is a classical relativistic particle? Is this a classical particle, one used in elementary physics classes and problems, traveling at relativistic speeds?

2. ### Google AdSenseGuest Advertisement

to hide all adverts.
3. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
I think so. It might be a good idea to clarify if it is in the general or special relativistic sense though.

4. ### Google AdSenseGuest Advertisement

to hide all adverts.
5. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

Messages:
8,967
Typically if we're talking about particles, we're neglecting gravity.

I am a bit confused, though. In what context was this term used, amadeus?

6. ### Google AdSenseGuest Advertisement

to hide all adverts.
7. ### James RJust this guy, you know?Staff Member

Messages:
35,782
"Relativistic" might mean "travelling at a reasonable fraction of the speed of light", or it might just mean "we're treating this particular using relativistic mechanics, rather than non-relativistic mechanics".

"Classical" just means "we're not using quantum mechanics in looking at the behaviour of this particle".

8. ### AmadeusboyRegistered Member

Messages:
22
Sorry for the lateness of my reply:

The expression comes from the title of a paper from Physics Review, "Presymmetry of Classical Relativistic Particles". I tried to wade through this paper while in college--I didn't make it very far--and recently, I came across it. I was going to spend a little (or possibly a lot) time trying to understand it. However, it has been a long time since I have studied any thing of this caliber and so this may be a lost cause. (I had to find the notes I had pertaining to this paper to refresh my memory of what "presymmetry" means. I believe I have a vague, if somewhat incomplete and possibly incorrect, notion of its definition.)

Also, I believe quantum mechanics is not discussed in the paper and the particle is treated using special relativity.

I am unclear as to why this is true. If I remember correctly, in elementary physics classes point particles were the first things studied.

Thanks to all for the responses,

Amadeusboy

Last edited: Nov 12, 2008
9. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

Messages:
8,967
The effects of gravity on a charged particle are about 10^{large number ~40} times greater than gravity. I'll check out your paper when I get to the office tomorrow.

10. ### rpennerFully WiredValued Senior Member

Messages:
4,833
$\left| \frac{F_{\mathrm{Electromagnetism}}}{F_{\mathrm{Gravity}}} \right| = \frac{\frac{1}{4 \pi \epsilon_0}\frac{q_e^2}{r^2}}{G\frac{m^2}{r^2}} = \frac{q_e^2}{4 \pi \epsilon_0 G m^2} \approx \frac{3.457 \times 10^{-18} kg^2}{m^2}$

For two electrons, this ratio is about: $4.166 \times 10^{42}$

For two protons, this ratio is about: $1.236 \times 10^{36}$

For two singly charged U-238 ions, this ratio is about: $2.213 \times 10^{31}$

http://www.google.com/search?q=what is (electron charge)^2/(4*pi*G*electric constant) ?

11. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

Messages:
8,967
Thanks for keeping me honest rpenner

Please Register or Log in to view the hidden image!

12. ### rpennerFully WiredValued Senior Member

Messages:
4,833
It's all part of the service. Still in California?