Fundamental forces, and related science questions

[Holly]

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[Holly]

I have found several videos and articles about rest mass but I continue to have a few questions:

Finally, let go of the common picture of a fundamental particle as some kind of very tiny, material pebble. When physicists refer to mass, they mean one of two identical kinds of mass, gravitational mass or inertial mass. The first means how much gravity it exerts, the second how much it resists change in motion. The two calculations always give the same number (thankfully).

This helps me get closer to understanding but I still have questions.

Here are my notes so far:
Inertia - The tendency of an object to resist a change in state of motion.
Or the tendency of an object to resist acceleration.

Inertial Mass: A measure of Inertia
A measure of an objects resistance to acceleration.

Gravitational mass and Inertial mass are experimentally identical.


1. The Photon is measured at rest, how do we actually know what the mass is when a Photon is not at rest?
2. According to the following link: http://www.desy.de/user/projects/Physic ... _mass.html
Light is composed of photons, so we could ask if the photon has mass. The answer is then definitely "no": the photon is a mass-less particle. According to theory it has energy and momentum but no mass, and this is confirmed by experiment to within strict limits.

Please tell me what are these experiments are? What is being measured or how? Especially since Photons are measured at rest?

[Faradave]

First, understand that "mass" by convention now refers specifically to "rest mass" the mass of an object in a frame of reference where it is at rest. This is also called the "invariant mass", "intrinsic mass" and "proper mass" of a particle for various reasons. For simplicity we'll stick with "mass".

Convention also allows no rest frame for a photon because it travels at the absolute speed limit c. Thus, it has no mass and is called a massless particle. Photons do convey energy. So what about E = mc²? Doesn't that mean photons have mass? Yes and no. Since we said "mass" means "rest mass" the answer is no. Photons don't have a rest frame. But photons have an effective mass.

It is often neglected to mention that the m in E= mc² refers exclusively to rest mass. The full equation is E² = (mc²)² + (pc)² where pc is the energy of motion. The energy of a photon is entirely of this variety. A photon's effective mass can be derived from that. It is also the increase in rest mass of an atom which has absorbed a photon.

A substantial portion of the sun's rest mass is attributable to the enormous number of photons still inside it. So, even though photons are always on the move, if the system they are in is at rest, they contribute to the system's rest mass.

There are many other vidz like this favorite of mine.

[hyksos]

Are the strings in String theory LITERAL or just a mathematical construct?

This question is very difficult to answer at any level of physics. We would have to make a whole thread to give it fair treatment. In rough terms, the answer is : we don't know.

In general, the perspective on the issue will fall into two broad categories :

(1.)
If you believe that our common, everyday notions of space and time are in some sense absolute, then you would be forced to conclude that the strings of String Theory are mathematical structures and not physical objects. The reason is because of something called T-duality. (again, we would need a separate thread on this topic to give it fair coverage.)

(2.)
If you have a more sophisticated and nuanced relationship to space, its geometry and its relationship to time, then you can eek out a claim that the strings of String Theory are actually physically-extant objects. The reason is because of M Theory. (without fair coverage) M Theory suggests that the geometry of space at distances smaller than the Planck Scale is very exotic and quite alien to how we experience it at human scales. The movement and vibration of strings would be determined by this geometry, just as expected by a normal object.

The argument between these two perspectives will not be resolved soon. Because the people who are adherents to part (2) will point out that T-duality itself suggests that (2) must be true. And round and round we go.

I am adherent to something that looks roughly like perspective number (1) -- but that is my personal opinion.

[Faradave]

Earlier, I wrote that the "object" we call the "eye" of a hurricane arises from spin.
It would be fair to suggest that a "string" could similarly be that which arises from a particular vibration.
Like information, energy will find or even define an object to represent it.

[Holly]

Faradave,

It's ironic that I BELIEVE that galaxies and Black holes form at the same time, like the eye of a hurricane. To my knowledge everything I read states we don't know what forms first galaxies or black holes. but I propose they form simultaneously.

Please forgive me if this falls under the "Personal Theories" section, I will attempt to refrain from that since I tend to have a number of them that are a bit out there.

By the way, I hope your rocking out to what ever resonates with you my friend. Yes, your my friend since you always take me seriously, don't talk down to me or make me feel stupid and you answer my call when I leave a message.

Thank you.

[Holly]

Finally, let go of the common picture of a fundamental particle as some kind of very tiny, material pebble. When physicists refer to mass, they mean one of two identical kinds of mass, gravitational mass or inertial mass. The first means how much gravity it exerts, the second how much it resists change in motion. The two calculations always give the same number (thankfully).

I like this solution or idea the best, it is more about the resistance of a "particle" in motion.
Photons are crazy! But so are so many other crazy particles and yes those darn cats that are dead and alive.

[Faradave]

...galaxies and Black holes ... I propose they form simultaneously.

You may be correct. We have a lot to learn about the distribution and participation of dark matter in relation to galactogenesis (another made-up term).

you always take me seriously, don't talk down to me or make me feel stupid...

Happy to help. Now that folks have had a chance to meet you, I'm sure you'll find it the norm at SPCF. It should be fine for you to open new threads as the need arises.

[socrat44]

Are the strings in String theory LITERAL or just a mathematical construct?
IF the strings are vibrating, WHAT causes them to have the energy to produce this vibration?
Is it possible if they are vibrating they cause noise or even music
(I hear they are like Violin Strings).

Music of the Spheres - Musica universalis

https://en.wikipedia.org/wiki/Musica_universalis
===

Pythagoras created the theory ''Harmony of the Spheres''
The spirit of Pythagoras idea went into Kepler's thinking
and in 1619 he published ''Harmonices Mundi''
( harmonies of musical intervals describe the motions of the planets )
#
The connection between music, mathematics, and astronomy
had a profound impact on history.
To continue this profound tradition modern physicists created
musical tools ( similar to known violin or guitar strings)
by name ''String Particles'' ( open and closed) in the hope
to hear the harmony of spheres.
=====

[Faradave]

Orbital resonance is a real phenomenon.