Does someone with an open mind want to try to tackle this? Its about a theoretical ant on a rubber string. If the ant is crawling on the string, but the string is expanding, can the ant ever reach the end. In the video they claim it can, because the ant’s progress gets stretched towards the end, at the same time the string is stretched. But this is a bizarre interpretation in my opinion. This is only true if the string is being stretched in only one direction, that is, the direction that it is approaching. So the string is secured at one end, and streched at the other end, so indeed it keeps getting closer to the end.
But if neither end is secured, and it is stretched, there is no reason for the ant to be stretched in the direction of its progress, thus it would never go anywhere. But neither the narrator, nor anyone in the comments seems to have a problem with this. Why?
And is this in any way analagous to spacetime stretching?
196 thoughts on “Something fun for a change…Ant on a rubber band.”
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phoodoo,
For what? Can you get a different answer by changing the frame of reference?
Alan Fox,
Is that what the quote I pasted is talking about Alan, the frame of reference? Do you understand what that quote says?
Which quote?
I do see the problem. That sentence is equally true whether the starting point is held in place and the target end is stretched, or alternatively if the target is held still and the starting point is pulled backwards.
I attempted (apparently without success) to convey this point with the phrase “whichever way one wants to measure it”. It is still true if the whole thing is traveling eastwards at 1,000 mph… as one does.
For the first six seconds, Billy is getting further away from the target point: if you use the frame of reference of the target point, he is going backwards. BUT, once he gets to the midpoint of the rope, he starts to close that gap. Whichever frame of reference you use.
The paradox does NOT depend on which end is stretched.
Alan Fox,
This is called a quote, from the wikipedia page YOU sited. You also don’t know what quote means?
Maybe Jock can explain it to you. Oh, but he is also pretending he doesn’t understand it. Or maybe he is not pretending, which is worse?
It’s “cited”. I didn’t cite the Wikipedia entry, I provided a hyperlink. You copied text but provided no reference.
Alan Fox,
What wikipedia entry? What ant? What rope? What do you mean….
Really tough one to figure out huh? Its on the webcite Alan.
Maybe you can read the “site” you posted.
phoodoo,
Maybe you can state clearly what your problem is.
Alan Fox,
If you can’t understand what that quote means, there is not much hope making it any clearer for you is possible.
Tell you what. You respond to this comment of mine and I’ll respond to whichever question you posed to me you select.
Here it is:
Alan Fox,
I didn’t pose any question to you. I showed why I have been right all along, and everyone else has been wrong. If you can’t understand what the wikipedia article about the ant on a rope, which YOU posted here for others to see is saying, then how can I help you. I have to explain to you what words mean? I have to read each sentence for you and explain it, while you say, “So, what quote, what about the reference frame, …yadda yadda…”
phoodoo,
So, reference frames? I say irrelevant. You say?
It’ll never happen Alan.
phoodoo is certain that, if the starting point is held still and the target is stretched, then Billy is carried along by the stretch, and can (at least for the 20,10, 5 video example, or the 4,2,1 wiki example) reach the end.
If, on the other hand, the target is held still and the starting point is stretched, then (per phoodoo) Billy is carried backwards and he can never reach the target.
phoodoo has discovered a ‘dependence on which end is pulled’ that the rest of the world has missed. Because phoodoo is correct about this, there is no amount of math or modeling or re-explaining that will make any difference. He will never engage on the math, since “Math has to reflect the real world” after all, and he knows that he is right.
phoodoo’s intuition is always correct.
And to think that we tried to discuss Lorentz with him.
DNA_Jock,
Haha, yea right Jock. Try to weasel out of it now. I said both ends stretched and you know it. That’s the point, there is no reason for the ant ot only be pulled in one direction-and now you see it, so you are squirming. the whole idea of the ant being pulled magically, while at the same time the part of the band underneath is pulled at a different rate then he himself is pulled is just silly nonsense. I already got you Jock. I quoted where I was right, not just once but twice.
Sorry a rice farmer outsmarted you. Really no need for an apology. I got ya.
If that is genuinely his position then there is indeed no hope.
phoodoo,
Not convincing, phoodoo. It’s right there in your OP and quoted in the comment of mine I drew your attention to.
I mean if you just want to play gotcha by fudging on the starting assumptions, you can play by yourself.
Alan Fox,
You are pathetic Alan.
From Op quote (read up on what quote means Alan)
Shut the fuck up. No need to apologize.
phoodoo,
Are you having fun?
As I said, this is wrong. The reference frame is irrelevant.
Fun! 🤣
All the ant needs to do to be ‘stretched in the direction of its progress’ is to walk a short distance from the dead centre of the rope, if one insists that that is a privileged frame of reference. This seems a trivial task for the average ant.
Conversely, if it were to wander across the dead centre from either side of it, it would appear that the ant suddenly finds itself unable to move, contradicting the evidence from its little legs, if the above were true.
Allan Miller,
Yeah, well, the first thing I tried with phoodoo was taking the ant’s frame of reference, but I was assuming a whole hell of a lot more comprehension than was available…
Back then, I was still trying to get him to understand the paradox itself, not realizing his unique views on stretching.
Does phoodoo notice that he fails to answer these specific questions?
DNA_Jock,
From the ant’s pov, if phoodoo was correct it would be able to tell where it was on the rope from what was going on under its feet. But I think all locations would actually feel the same, myself – an equal sliding motion in both directions wherever it was. Even at dead centre, being of a non-point persuasion its back feet would be feeling a westward slide and its front ones an eastward one.
Allan Miller,
Yes. quite, but that harkens directly back to another thing we tried to explain to phoodoo: in a uniformly expanding universe, phoodoo would think he is in the middle of the expansion, wherever he happens to be.
Much fun was had by (nearly) all.
Does the universe have an edge? I know the flatlanders on an expanding balloon could not conceptualize that the edge lies in a dimension inaccessable to them. Would this be the same for us?
Flint,
Oh, I resolutely avoided going there. I have no opinion on the topology of the universe. I merely noted, in the previous conversation, that even if the universe has a center, one cannot use the observed distance vs speed correlation to conclude that one is near the center. I was making a mundane point about geometry.
He never got beyond ants and rubber bands. He never penetrated the decoration and thought about the underlying puzzle itself and he doesn’t realize. Quite fascinating.
This thread encapsulates what it means to be an ID supporter, it seems.
It seems literally everybody who has given an opinion says you are wrong.
Why? There is no evolution or religion involved. Morton’s demon must be idling.
Ah, yea!!! Not If I was correct, let me just correct you.
The light just went off in your head.
Wait, wait, what??? There is a center? A CENTER?? You just gave Jock a heart attack, please, please have some compassion. A center you say? Oh, and its trivial to get past that. Whew, that’s a relief, its only trivial.
From whose frame of reference is there a center Allan? Because this is the new talking point. Since I have already shown that I said exactly what I said, and exactly what I said is ALSO exactly what is true (that it does matter where it is stretched from) , what does this new “frame of reference” have to do with anything?
As you have correctly noted, what the ant would ACTUALLY experience, is NOT being pulled in only one direction but being pulled in TWO directions, surprise surprise! So remember when Jock said it doesn’t matter at all what direction the rubber is pulled from, remember when he was full of shit then? And by the way, this has always been my contention, that the paradox is stupid because it is assuming the ant only gets pulled towards the end, when in fact his feet are being pulled both ways (Jock didn’t get this, Alan doesn’t get this, Flint doesn’t get this, Graham didn’t get this, Corneel didn’t get this…but, but, butt.)
So now you are going to back him by saying, oh, well, its TRIVIAL getting past halfway…oh, ho,ho,ho..boy that’s a good one. It’s trivial! I am going to save this one. When you want to weasel your way out of being wrong, just say—but its trivial!!!
Now about that center again, Jock thinks centers don’t matter. You see there is no center to the universe, so how can there be a center to a rubber band. The is no difference between the center and every other point.
So I love this, you were all SPECTACULARLY wrong. And now Corneel and Flint are going to say, Gee, Jock, you really showed him, being so wrong and all-because you know you are wrong but trivial…
Again, no need to apologize. Just say its trivial, then I will know what that means.
ID supporters prefer, it seems, their explanations to be in “plain text” rather then a more objective mathematical form that can be tested and examined rigorously.
phoodoo refuses to engage on the actual mathematics, much like ID supporters refuse to engage in the actual science. It’s clear he has a disdain for formalizing his claims in mathematical forms that can reduce ambiguity. ID thrives in the gaps.
phoodoo’s conflation of multiple issues into a gish-gallop that is just not worth untying, as per his last comment, is par for the ID course.
All I’m saying is that it’s no surprise that someone making the sorts of arguments they are making in this thread is also an ID supporter.
This bears repeating. phoodoo prefers to spew out a wall of text, to obfuscate not to clarify, when he could actually refine the mathematical model instead.
So there’s a specific atom that is precisely between the two ends, and the center of the ant is also exactly on that single atom? Is that what you mean?
Not sure that is true. IDers like Bill Dembski and Eric Holloway clearly love to have their explanations in a mathematical format (not commenting on the quality). It is true that most ID supporters are in no position to evaluate the mathematical theory but in what way is that different from a pro-science layman public?
Sure, but that is usually restricted to matters concerning evolution and Intelligent Design. Outside of these topics ID creationists function like every other person. There are several examples of (ex-)IDers and YECs that succesfully pursued a scientific career, typically outside of biology.
This thread has nothing to do with evolution. I believe that phoodoo genuinely intended the current OP to be a lighthearted diversion, so I am a little surprised it turned into the usual flame war.
phoodoo,
You seem to be trying to obfuscate with trademark excitability. Yes, the rope has a centre, I don’t think anyone is arguing otherwise, but if the net stretch is contributed to equally from every arbitrary equal subdivision, the ant has no way of knowing where that is. The rope does not behave differently at the centre, nor at any other equivalent point between the fingers of the Celestial Stretcher. It just slides at the same rate under front and back feet at all points (unless we have taken the precaution of glueing it in place, in which it will indeed get nowhere, having snapped).
Me too
The ant’s carrying baggage.
Allan Miller,
That’s right Allan, which is why I also noted that it is silly to assume the ant should be “advanced” in the direction of its travel, given that it should be being stretched in both directions simultaneously. That is the whole nature of expansion. Everything is part of that expansion in all directions (another thing Jock doesn’t get). The ant isn’t being pulled in one direction, it is constantly being pulled in two directions-as you correctly noted.
Another way to look at it is to imagine the rubber band as a two dimensional loop instead. As it exapnds, the ant is not pulled in either direction, rather it is being pulled apart. Giving it a direction is introducing a false premise. Instead, it is increasing the overall space, so that everything becomes further away from everything else, not closer. Its trickery.
I suppose it’s a fire ant.
For s&g, I plotted the results for three ‘different’ scenarios. In each case I am using the parameters from the video (L=20cm, S = 10cm/s, A = 5cm/s) and I am calculating discrete intervals every 0.1 seconds (with conservative application of stretch).
The Yellow line plots the absolute position of the ‘target’ end of the rope.
The Black line plots the absolute position of the ant.
Top: Hold the start still, and stretch from the target end.
Middle: Stretch equally from both ends.
Bottom: Hold the target end still and stretch from the start end.
These three different scenarios will lead to dramatically different times to reach the end. [Holds finger to earpiece] What’s that you say?
I’ll get me coat.
phoodoo,
Nope. You need to choose a frame of reference and stick with it, if you think frame matters. The ant doesn’t know there’s a component of motion due to stretch – there isn’t, in its reference frame. It only sees local, equal stretching. But there is, except at dead centre in the both-ends-stretched reference frame. ‘Out here’, as observers of the whole, we can see an off-centre ant being displaced from its prior position even if it’s got its boots off and rubbing its feet. For a ‘centre ant’, off-centre is but a step away.
Oh sure, and they get engaged on that level and that’s also fun too.
But for most they are just happy to know that something that looks like maths that supports their pre-existing belief is out there, and that’s true on all sides to some extent sure.
But phoodoo implys he’s more then a layman elsewhere. And here we have people offering to engage with phoodoo at a mathematical level but he prefers to brush them off with insults instead. Hence demonstrating he’d rather deal with it at the rhetorical level then engage with the modelling side.
I myself was much surprised to find one of my colleagues at a programming shop was an ex YEC but still a full on creationist.
He did display a pig pigheadedness to ever being wrong that would seem to support the case I seem to be building here however. ;P
I was happy to leave him to it until he turned on the usual charm, for sure.
Perhaps an interactive model with parameters you can tweak would answer the question phoodoo?
Want me to build it? heh
Allan Miller,
Oh…so you mean if you put dots on a rubber bands and stretch the rubber band, the dots are going to stay the same then? Since from their frame of reference nothing changes. Gee, let’s do an experiment. And then after we do the experiment you can apologize to me again.
Your apology will probably be something like..its trivial.
Wrong again.
phoodoo,
Declaring victory without the preliminary stage of putting in any kind of reasoned argument is rather disappointing.
Alan Fox,
You mean one you can understand?
Be realistic.
You still haven’t even read the Wikipedia page.
I doubt that and seems perverse of phoodoo to suggest it. Still, you could try explaining why an ideally elastic rope stretch is affected by anything other than the distance between the two ends.
DNA_Jock,
For those who missed Jock’s attempted sleight of hand.
WTF???
This is why it’s unrealistic to explain it in a way you can understand.
Alan Fox,
I would love it if even one other person could say they understand what you are trying to say here. Even if they lie and say they understand, I would love to see that.