The discussion centers on the concept of infinity in the physical universe, questioning whether anything can be considered infinite or unlimited outside of mathematical constructs. Participants explore various aspects of infinity, including its implications for the size of the universe, the number of particles, and the nature of physical quantities.
Participants do not reach a consensus on the nature of infinity in the physical universe. Multiple competing views are presented, with ongoing debate about the implications of infinity for the universe and physical quantities.
Participants acknowledge limitations in current understanding, particularly regarding the definitions of particles and the nature of physical quantities. The discussion highlights the challenges in confirming the infinite nature of the universe versus finite models based on observational evidence.
I said before that the speculation that the universe is infinite can never be confirmed.PeroK said:That's a big if. Let's assume it's true. Describe your experiment. How do you organise such as experiment. It's not enough, IMO, to wave your hands at the infinite cosmos and say it's happening!
The question is what experiment do you have in mind to detect and count the infinite number of events?anorlunda said:I said before that the speculation that the universe is infinite can never be confirmed.
But neither could a limit on the number of events per second in a single spot be used to give evidence about the extent of the universe.
I have not read every post. Does your point apply the the Planck length also?PeroK said:Here's an example of the difference between maths and physics.
If we imagine one event at time ##\frac 1 2## second. Then another event at time ##\frac 3 4## second. A third event at time ##\frac 7 8## second etc. Then, mathematically we have an infinite sequence of events within ##1## second.
But, you cannot do this physically. You might argue that there is no limit to how quickly the events can happen one after the other. Whatever limit anyone specifies you might be able to do better. But, you cannot go on indefinitely making the increment smaller and smaller. If you try to generate an infinite number of events in finite time, you must hit a limit somewhere.
One example might be how fast a computer can count. It's impossible to put an absolute limit on it, but any given computer must have a limit.
What does it mean for a thing to be "there" if you cannot measure it?pinball1970 said:Is Planck length/2 a meaningless statement in terms of existence rather than measurement?
It is there we could just never measure it?
jbriggs444 said:What does it mean for a thing to be "there" if you cannot measure it?
jbriggs444 said:To me the answer is that Planck length / 2 is there in the model. But the model may have features beyond what the reality requires.
We suspect there are. It makes our theories simpler to assume that there are. But the true state of affairs is "we do not know".pinball1970 said:There are things in the universe that we cannot measure that are there like very distant galaxies? Or strings? Dark matter?
Perhaps I'm misunderstanding the concept, but with the electromagnetic spectrum, can it really be partitioned into an infinite number? Is it not constrained by the shortest wavelength?Drakkith said:The number of partitions something continuous can be divided into, such the space between two points or part of the electromagnetic spectrum, is infinite.
Yes, though I think what you are getting at is that we cannot measure the difference between two possibly different wavelengths to infinite precision. So, for all we know, there might only be finitely many possible wavelengths.Melbourne Guy said:Perhaps I'm misunderstanding the concept, but with the electromagnetic spectrum, can it really be partitioned into an infinite number? Is it not constrained by the shortest wavelength?
Within the classical theory of EM there is no such thing as the shortest possible wavelength. Or the longest.Melbourne Guy said:Perhaps I'm misunderstanding the concept, but with the electromagnetic spectrum, can it really be partitioned into an infinite number? Is it not constrained by the shortest wavelength?
True about the theory, but still a red herring when it comes to physicality.PeroK said:Within the classical theory of EM there is no such thing as the shortest possible wavelength. Or the longest.
There's a difference betweenDaveC426913 said:True about the theory, but still a red herring when it comes to physicality.
I have already pointed out practical limits on upper and lower bounds.
I know, and I'm not disagreeing that it's valid; I'm simply pointing out it's a red herring in a discussion about physical phenomena.PeroK said:There's a difference between
A) An EM wave theoretically having any non-zero finite wavelength.
B) an EM wave having a wavelength of zero or "infinity".
The first is what the classical theory says.
The number of different frequencies between 100 MHz and 101 MHz is infinite for example. The shortest or longest possible wavelength is different and not what I was referring to.Melbourne Guy said:Perhaps I'm misunderstanding the concept, but with the electromagnetic spectrum, can it really be partitioned into an infinite number? Is it not constrained by the shortest wavelength?
Well, infinite basically means no limit. Empty space or void that is totally devoid of everything has no limit. So, there you go. But empty space that is totally devoid of everything is just hypothetical. If empty space is nothing more than the totality of electrons, then this is another example of infinite in the real world.LightningInAJar said:Summary:: Is anything in the physical universe unlimited or just in math?
Is anything in the physical universe unlimited or infinite or does Infinity only exist to make some math work? Is Infinity a real thing outside of math?
Both zero and infinity are the same if you're a critical thinker. Both possessed no limits at all. What you're trying to tell me is incessant or nonstop moving such as like an ant walking incessantly on a ball. People confused unbounded part of the "finite but unbounded universe" hypothesis with incessant motion on something.Good Elf said:@wonderingchicken:
To see a World in a Grain of Sand
And a Heaven in a Wild Flower
Hold Infinity in the palm of your hand
And Eternity in an hour...
The meaning of any word has no absolute applicability. There needs to be agreement—an applicable lexicon. Words require a full context. One way to think of infinity in Math is to divide 1 by zero... that is an infinity but can any human mind fully grasp what it means? The result of this division is a number bigger than any human mind can comprehend or ever write down—it size may be approached—but adding a single digit makes it 10 times bigger than before... without any limits, a number raised literally to infinity in tenfold steps, yet it is so easy to write this as a 'simple' fraction... to comprehend it is quite another thing entirely.
Saying something has no limit is also 'highly qualifiable'. You said "infinite basically means no limit". If I said you could run away with 'no limit'... would you get to infinity? It is conceivable that the further away you escape to, the closer you will be to where you first left because our Universe may be unbounded yet finite like a bug caught on the inside of an inflated balloon, it can walk forever but never reach infinity, actually it can't even get out to a distance greater than the size of the balloon. The surface of the Earth is like this—unbounded yet finite (only curved in the opposite direction). Like bugs... we live in 'Plato's Cave' with bodies formed in & by that environment. There are limits to what is directly seen.
Being totally devoid of anything is not infinity—it is a zero. "If empty space is nothing more than the totality of electrons, then this is another example of infinite in the real world". We are in fundamental disagreement about the use of the word 'electrons' being equated to 'empty space' & 'infinite'. Space being empty of everything... what is the difference between infinity & zero? You must tell me... first!
Although it may sound poetical to say that no one understands mathematics, it's not the case. The mathematics of infinite sets is well understood by any competent mathematics student.Good Elf said:One way to think of infinity in Math is to divide 1 by zero... that is an infinity but can any human mind fully grasp what it means? The result of this division is a number bigger than any human mind can comprehend or ever write down—it size may be approached—but adding a single digit makes it 10 times bigger than before... without any limits, a number raised literally to infinity in tenfold steps, yet it is so easy to write this as a 'simple' fraction... to comprehend it is quite another thing entirely.