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Forum » SpaceEngine » Science and Astronomy Discussions » Science and Astronomy Questions
Science and Astronomy Questions
WatsisnameDate: Sunday, 19.06.2016, 02:06 | Message # 511
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Just a name. smile It's like calling protons "positively" charged, and electrons are "negatively" charged. In this case, color comes from a field called Quantum Chromodynamics (QCD), where color charge is a name for three types of strong interaction. Whoever named it thought that since human vision is tri-chromatic, and here we have three types of "charge", that calling it "color charge" would be cute.

Of course, particles at this scale have no such thing as "color" in the way we usually think of color as a visual sense. Similarly, "top/bottom" or "up/down" don't really mean those things in the quantum world -- it's just a way of naming properties and interactions. Even the idea of "spin" doesn't describe what electrons are really doing. They're not like little spinning tops. They just happen to have an inherent angular momentum, so we call it spin.

My favorite quark names are the "strange" and "charm". And for a while people wanted to use "truth" and "beauty" for the top and bottom quarks, though those didn't stick. Cute names, but a particle knows nothing of beauty or truth or strangeness or color. At least I'm pretty sure -- to be fair I've never asked one. biggrin





 
spacerDate: Sunday, 19.06.2016, 02:10 | Message # 512
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yeah that names more friendly to ppl who isnt professors in that stuff!
but i want to know. what the colors are! how blue qwark is different than red or green quark.

also what is that spin? i try to understand it. i know bosons have spin of 1 or 0 (bosson higs)
and the quarks have spin of 1\2.





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HornblowerDate: Sunday, 19.06.2016, 02:22 | Message # 513
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NOTHING make the strings.

So what if you took a string and cut it with another string? Is 1 string made up of 2 half strings? And what properties do they have?
 
WatsisnameDate: Sunday, 19.06.2016, 02:52 | Message # 514
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Quote spacer ()
but i want to know. what the colors are! how blue qwark is different than red or green quark.


Mmm, try thinking about this:

What makes positive charge different from a negative charge? If I gave you three objects, A, B, and C, and you find that A and B attract, A and C attract, B and C repel, and all three attract small, neutral bits of paper, then can you tell me which are positively charged and which are negatively charged?

You cannot.

What you can do is make a model which says that there are two types of "electric charge", and if two objects have the same charge, then they repel, and if they have opposite charge, then they attract. Then according to this model, B and C have the same charge, and A has the opposite charge, but you don't know which is which. You can do a lot more experiments with other charged objects to further support your model that there are only two types of electric charge and that they interact in this way. And you can dive into the study of atomic structure and discover what the charge carriers themselves are -- the protons and electrons -- but your decision of "which is positive and which is negative" is still completely arbitrary. It doesn't matter as long as you stay consistent with your choice.

Same (or at least similar) idea with color charge. There's nothing about a quark that tells us "I have a red charge". Instead we observe that there are three types of strong interaction, and we can model them as being due to three types of "color charge" (there are also anti-color charge for the anti-quarks). What the color charge does is describe the interaction of quarks by exchanging gluons.





 
spacerDate: Sunday, 19.06.2016, 10:19 | Message # 515
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Watsisname, and what exactly is the spin?
its a movement?





"we began as wanderers, and we are wanderers still"
-carl sagan

-space engine photographer
 
WatsisnameDate: Sunday, 19.06.2016, 11:58 | Message # 516
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The unsatisfying answer is that it is not, and describing what it really is is hard. This gets into the weird, un-intuitive world of quantum mechanics.

An electron's spin is like a spinning ball, but it isn't. They are not balls and they are not spinning. You can make a spinning ball spin faster or slower. You cannot do that to an electron. You can turn a spinning ball to make it spin on any axis. Again, cannot do that to an electron. Electrons don't even "move" in the usual sense. Most of our every day experience of the behavior of objects fails when we apply it to quantum mechanical systems.

For example, a common description of an atom is that electrons orbit the nucleus like planets orbiting a star. That description is way wrong. If electrons actually moved that way, then they would be strongly radiating (accelerated charges radiate), thereby losing orbital energy, and crash into the nucleus in a tiny fraction of a second. All atoms would collapse and we would not exist!

Electrons instead exist more as a fuzzy cloud of probability. There is a probability function across the space of the atom that describes how likely it is for the electron to be found there. Which is weird and unsatisfying, but that's how it works.

Back to "spin", this originally comes from concepts in electromagnetism. The magnetic properties of electrons are similar to that of a tiny, spinning charge. It's almost as if the electron is a little loop of circulating current. So physicists started referring to this property as spin, even though that's not what they are really doing. Instead it is an inherent quality of angular momentum. Subatomic particles have angular momentum in discrete amounts (the angular momentum is 'quantized'). And they have this quality without actually spinning. Which is weird and unsatisfying, but again that's how it works. biggrin





 
steeljaw354Date: Sunday, 19.06.2016, 13:20 | Message # 517
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So nothing makes a string then, so everything is basically nothing?
 
MosfetDate: Sunday, 19.06.2016, 14:52 | Message # 518
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I think it could be more correct, if the string is the ultimate constituent of matter, that the string simply "exist".




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spacerDate: Sunday, 19.06.2016, 15:16 | Message # 519
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Watsisname, ok thank you very much!!
i will continue to learn that throught the summer vacation. smile





"we began as wanderers, and we are wanderers still"
-carl sagan

-space engine photographer
 
steeljaw354Date: Sunday, 19.06.2016, 15:54 | Message # 520
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So how can nothing make something?
 
spacerDate: Sunday, 19.06.2016, 16:17 | Message # 521
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Quote steeljaw354 ()
So how can nothing make something?

its really hard question i think noone can explain. its like asking how the big bang happend from nothing.
it is happend. It doesn't make any sense to talk about strings as being "made-of" anything. The point of string theory is to create a unified theory of fundamental particles. If they were "made of " something, then they wouldn't be "fundamental" the thing they were MADE OF would be the fundamental thing. also a string if exist is the lenght of a plank. nothing smaller than that can exist in spacetime.
the strings probably been made in the big bang that we cant really know how and why it happend





"we began as wanderers, and we are wanderers still"
-carl sagan

-space engine photographer


Edited by spacer - Sunday, 19.06.2016, 16:18
 
MosfetDate: Sunday, 19.06.2016, 16:27 | Message # 522
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Quote steeljaw354 ()
So nothing makes a string then, so everything is basically nothing?

No.

Quote steeljaw354 ()
So how can nothing make something?


This is known as a Conundrum, it's a logic trap created by word meanings.

The meaning of "Nothing makes a string" is that a string is the ultimate boundary of the matter, just as Big Bang is the ultimate boundary on the other direction.
What we can learn with science and technology stops there, for now.

Strings, quarks, colors, wave-particle duality: these are all terms borrowed by the material world we experience to grasp some difficult and anti-logic result from mathematical analysis and scientific experiments. Our everyday language is scarcely able to picture those results, so we use is somehow to approximate reality.

Unfortunately the one and only language that better it represents the entirety of physics is mathematics. Beware, it's an approximation too :)

If you think about it, you're typing on a keyboard right now by commanding electrons and electromagnetic fluxes to transmit your thoughts around the globe thanks to technology based on mathematical rules. Space Engine itself is a simulation made by mathematical algorithms in order to paint photons on a surface in a way that our limited senses can assimilate.

It's a new point of view that matters smile





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Edited by Mosfet - Sunday, 19.06.2016, 16:45
 
quarior14Date: Sunday, 19.06.2016, 16:33 | Message # 523
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I want to know how the lifetime and age of a star is determined. I know it is linked to mass but there are what ? What is the equation/demonstration to determine this (lifetime and age) ?




Quarior
 
MosfetDate: Sunday, 19.06.2016, 16:50 | Message # 524
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That would be the Hertzprung-Russell diagram, if I remember well.




"Time is illusion. Lunchtime doubly so."
Douglas N. Adams
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spacerDate: Sunday, 19.06.2016, 22:28 | Message # 525
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it really intersting that there could be a particle we didnt discovered yet that cause the gravity.
the name of the particle is graviton, and has a spin of 2.
its gonna be so hard to discover such particle because the gravity force is weak compare to the others forces.
we discover the particle of electromagnetism (photons) the weak nuclear force (bozons Z and W)
and strong nuclear force (gluons)
but still no particle of gravity! its gonna be big challenge to find it





"we began as wanderers, and we are wanderers still"
-carl sagan

-space engine photographer


Edited by spacer - Sunday, 19.06.2016, 23:01
 
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