Practical Infinities

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MrTomServo
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Perhaps some of our more physics-minded friends can help out here. In a given distance -- say, a foot-long ruler here -- some would say there are an infinite number of points along the ruler. (That is to say you could take the smallest two markings, divide in half, divide that in half, divide THAT in half, etc.)

But is that actually physically true? Mathematically, yes, you can divide a distance until the cows come home. But physically, is there a fundamental granularity to the fabric of space (smaller than the realm of protons and neutrons) that we cannot divide?

I'm trying to prove my seventh-grade maths teacher wrong. She was a bitch anyway.

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Dr Lobster*
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whether you believe in unified theory or not, in my mind, i would say there has to be a fundermental building block to everything (these may be called 'quarks', if memory serves) but then, you get into this awful paradox of what the building block is made from, so maybe, there isn't one. i really don't know. it hurts my head thinking about it.

some people believe that everything is made from waves, so maybe there is no tangible solid building block, but rather a 'field' of some sort (like gravity)
noelfirl
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Quantum Physicists will tell you that the smallest particles, the fundamental building blocks of matter are quarks and leptons (the electron being a lepton, and neutrons and protons being made of quarks). So, I would assume that the smallest, undivisable pieces of matter are single quarks and/or leptons. Of course, it's possible that quarks/leptons are made of even smaller, more fundamental particles that have not been discovered yet.

But don't trust me, I had an android for a physics teacher in secondary school, who wore the same red jumper every day!
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MrTomServo
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noelfirl wrote:Quantum Physicists will tell you that the smallest particles, the fundamental building blocks of matter are quarks and leptons (the electron being a lepton, and neutrons and protons being made of quarks). So, I would assume that the smallest, undivisable pieces of matter are single quarks and/or leptons. Of course, it's possible that quarks/leptons are made of even smaller, more fundamental particles that have not been discovered yet.
Right -- I understand that bit, but I'm talking about the stuff that the quarks and leptons move around in. They exist in space (somehow). The question is, is there an indivisible unit of space itself?

Can a quark move like this?

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Or can it only move like this?

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noelfirl
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MrTomServo wrote:They exist in space (somehow). The question is, is there an indivisible unit of space itself?
No idea. But, if I was to just give an opinion, there may well be an actual unit of space, just that it is far far too miniscule to even comprehend, let alone measure.

And I'd say IMO that quarks probably move freely (the first picture).
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Sput
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MrTomServo wrote:
noelfirl wrote:Quantum Physicists will tell you that the smallest particles, the fundamental building blocks of matter are quarks and leptons (the electron being a lepton, and neutrons and protons being made of quarks). So, I would assume that the smallest, undivisable pieces of matter are single quarks and/or leptons. Of course, it's possible that quarks/leptons are made of even smaller, more fundamental particles that have not been discovered yet.
Right -- I understand that bit, but I'm talking about the stuff that the quarks and leptons move around in. They exist in space (somehow). The question is, is there an indivisible unit of space itself?

Can a quark move like this?

Image

Or can it only move like this?

Image

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Can it move at all? Is it a wave or a particle? What fun!

On the subject of spacial measurement, or maths really, things get even more odd. Measurement, like mathematics, is just an invention by humans to interpret the universe around us. There could be all kinds of crap going on at the subatomic levels that measurement has to account for.

That being said, these fundamental particles really can't be thought of as tiny balls making up bigger balls (hello!), that's just a nice easy way for us to think about them (well until real physics courses anyway). So to try and measure things in that sense doesn't QUITE work either! At that level, you're also getting into the interchangability of matter and energy!
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Brad
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noelfirl wrote:But don't trust me, I had an android for a physics teacher in secondary school, who wore the same red jumper every day!
That's alright, my science teachers cousin is appearing on the next series of 'I'm a Celebrity...'! I'll give you a clue, I was taught by a Mr Backley. ;)
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"That one!"
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MrTomServo
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Sput wrote:Can it move at all? Is it a wave or a particle? What fun!

On the subject of spacial measurement, or maths really, things get even more odd. Measurement, like mathematics, is just an invention by humans to interpret the universe around us. There could be all kinds of crap going on at the subatomic levels that measurement has to account for.

That being said, these fundamental particles really can't be thought of as tiny balls making up bigger balls (hello!), that's just a nice easy way for us to think about them (well until real physics courses anyway). So to try and measure things in that sense doesn't QUITE work either! At that level, you're also getting into the interchangability of matter and energy!
Count on Sput to come through in the end! (Hey now!) Suddenly I realise that it's much more complex than just dividing things in half until one can't divide anymore. From what I've read about it today, the whole subject is tightly integrated with String Theory, and that quarks themselves might actually be tiny loops of vibrating string, literally weaving the fabric of space.

But the question is still there: is there an absolute minimum size (in the same way that there is a minimum temperature)? Not that I'm asking for a number, but perhaps a proof of concept.

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Jamez
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I'm surprised how brainy you all are!

I feel left out now! :cry:
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Sput
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Jamez wrote:I'm surprised how brainy you all are!

I feel left out now! :cry:
Awww don't fret. You can hold my things while I talk!

and MrToms! I'm not finished with you yet! There is no minimum temperature, absolute zero is in fact theoretical but is never reached because nothing is perfect like that :)
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MrTomServo
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Sput wrote:
Jamez wrote:I'm surprised how brainy you all are!

I feel left out now! :cry:
Awww don't fret. You can hold my things while I talk!

and MrToms! I'm not finished with you yet! There is no minimum temperature, absolute zero is in fact theoretical but is never reached because nothing is perfect like that :)
True, but I'll settle for theory!

(Story of my life, sadly.)

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