A revolution in thought

[thedoc]

Originally Posted by peacegirl

I had to spoon feed half of chapter one and two to you, so you have no room to talk.

You have never spoon fed anything to anyone, in fact you have demanded that people read your fathers drivel when they want answers to questions about the book. You have repeatedly refused to spoon feed any information to anyone, telling them to read the book to find the answers, which was a real joke for reading a joke of a book.

[peacegirl]

Originally Posted by peacegirl

Lone Ranger, you don't even know what his observations were,

You have never, not even once, provided us with an actual example of any observations he made. Sure, you've given us some claims that he made (most of which are demonstrably false), but that's hardly the same thing.

I am not flailing about in search of an excuse.

Originally Posted by The Lone Ranger

Liar.

Whatever.

I'm trying to understand why we would not be able to see the difference in size due to the inverse square law.

Originally Posted by The Lone Ranger

Liar. What's more, you've just demonstrated that you don't know what you're talking about.

So help me understand.

The principle in physics that the effect of certain forces on an object varies by the inverse square of the distance between the object and the source of the force. The magnitude of light, sound, and gravity obey this law, as do other quantities. For example, an object placed three feet away from a light source will receive only one ninth ( 1/32, the inverse of 3 squared) as much illumination as an object placed one foot from the light.

Inverse-square law | Define Inverse-square law at Dictionary.com

I still don't understand where you came to a 10% apparent difference rather than a 30% difference, which would be noticeable.

Originally Posted by The Lone Ranger

I]Then do the 4th-grade-level math.[/I] You have repeatedly claimed that you understand the inverse square law. So either do the math for yourself and see where the number comes from or admit that you were lying -- yet again -- when you made that claim.

Instead of telling me I'm a liar, why can't you explain the numbers to me. I understand the concept but you need to explain how this law relates to Roemer's observations.

Hell, even a 10% difference in size would be noticeable, and it would not take special instruments to detect it. Who are you kidding?

Originally Posted by The Lone Ranger

Really? So, I tell you what. I'll provide you with 2 pictures; one of them is a picture of an object that is 10 pixels across and one is 11 pixels across. I won't tell you which one is which. You'll get the first picture today. You'll get the second picture 6 months from now. Or maybe I'll just show you the same picture again.

If you can tell me which is object is 10% bigger than the other -- or if one of them is 10% bigger, then I'll believe you. (Here's a hint: you can't do it. Nobody can.)


Never mind; I'll make it really easy for you. One of these lines is 10% shorter than the others. Do be sure to tell us which one it is -- without counting pixels. According to you, it should be obvious.

If no one was purposely looking for it, it would probably go unnoticed. Could you please explain again apparent size versus actual size? And please stop being so snippety.

[Dragar]

The inverse square law isn't even a physical law. It's a basic property of geometry.

[thedoc]

Originally Posted by peacegirl

I'm not trying to criticize a minor point. This is a legitimate question. Think about it. We're talking about light traveling for an extra 17 minutes. That would be enough of a distance for Roemer to see Io much smaller than his first observation. Can people find any information on this?

No, it is not a legitimate question, it is nitpicking bullshit, just the kind of thing that someone would bring up when they have nothing else to work with. You have no points of proof to negate afferent vision, so you pick on the most obvious point that science doesn't deem worthy to comment on. The size of the image is accepted and understood by any sane person with 2 working brain cells to rub together, which apparently leaves you out because you have none at all.

[thedoc]

Originally Posted by peacegirl

And please stop being so snip-pity.

And I suppose that you will deny being snip-pity for the last 3.5+ years, another lie.

[peacegirl]

Originally Posted by Dragar

The inverse square law isn't even a physical law. It's a basic property of geometry.

So why do they call it a law then?

[thedoc]

Originally Posted by thedoc

No, it is not a legitimate question, it is nitpicking bullshit, just the kind of thing that someone would bring up when they have nothing else to work with. You have no points of proof to negate afferent vision, so you pick on the most obvious point that science doesn't deem worthy to comment on. The size of the image is accepted and understood by any sane person with 2 working brain cells to rub together, which apparently leaves you out because you have none at all.

I should apologize, as I now come to realize that a person has to have a working brain to form a lie.

[peacegirl]

Originally Posted by thedoc

No, it is not a legitimate question, it is nitpicking bullshit, just the kind of thing that someone would bring up when they have nothing else to work with. You have no points of proof to negate afferent vision, so you pick on the most obvious point that science doesn't deem worthy to comment on. The size of the image is accepted and understood by any sane person with 2 working brain cells to rub together, which apparently leaves you out because you have none at all.

Your anger only shows me that you can't deal with the fact that I'm thinking clearly and am entitled to ask questions. You just can't handle my resistance since you're so sure that Lessans was wrong. Well I've got news for you, the verdict is still out. I have the right to ask for an explanation that makes sense to me, and if you don't like it then leave. There should be a way to measure the difference in size of Io with instruments (like Lone Ranger said), if not by the human eye.

[thedoc]

Originally Posted by peacegirl

So why do they call it a law then?

You have never studied geometry? There are laws in geometry, and axioms, and theorems. Look at a book, other than your fathers joke of a book.

[peacegirl]

Originally Posted by thedoc

You have never studied geometry? There are laws in geometry, and axioms, and theorems. Look at a book, other than your fathers joke of a book.

You're a joke!

[Dragar]

Originally Posted by peacegirl

So why do they call it a law then?

You understand 'law' is a terrible word for description, right? It's an archaic throwback to how people viewed the world back in the pre-1900s.

Surely you know the area of a sphere goes as the square of the radius, right peacegirl? That's all the inverse square law is about.

[The Lone Ranger]

Originally Posted by peacegirl

Could you please explain again apparent size versus actual size?

Seriously?


Okay, let's start at the beginning. It is the difference between how big something looks from a particular vantage and how big it actually is. Got that? When you've mastered that concept, we'll move up to more complicated things, like 1 + 1.

[thedoc]

Originally Posted by peacegirl

There should be a way to measure the difference in size of Io with instruments (like Lone Ranger said), if not by the human eye.

If you would actually read TLR's post, he did state that astronomers have measured the difference in size of the image of Io, using instruments that were made for the purpose.

[thedoc]

Originally Posted by peacegirl

Your anger

I am angry because you are so obtuse and willfully ignorant that it is frustrating trying to explain anything to you. Even my students, who didn't want to be there, showed more ability to grasp and understand what I was trying to tell them. You pick at the most obvious detail and pretend that you don't understand, when it is obvious that you are just being stubborn and trying to derail the explanation.

[thedoc]

Originally Posted by peacegirl

You're a joke!

Thankyou, can I put that on my resume?

[But]

Originally Posted by The Lone Ranger

Jupiter (and thus Io) is only about 33% closer to us at closest approach than it is when it's at its farthest from us. Thus, there's only about a 10% apparent difference in Io's size between when it's closest to us and when it's farthest from us.

This has been well known and understood for centuries.

What is the apparent size here? Is it the angle subtended by its diameter in the sky?

I get something like

tan(alpha/2) = r/d

where r = Io's radius, d = its distance from Earth and alpha = its angle in the sky

so the ratio would be (alpha/alpha') = arctan(r/d) / arctan(r/d') which is approximately (d'/d) since r is small compared to d, so the angle should be about 50% larger when it's 33% closer.

Am I missing something here?

[The Lone Ranger]

Probably not. I did a quick, seat-of-the pants estimate, so didn't bother to do the actual calculation. A rough idea was what I was after. Given Io's apparent size from Earth with the telescopes available in Romer's time, the apparent size difference would have to be pretty big to be readily noticeable.

[But]

Maybe peacegirl will enlighten us what the whole point is this time around.

[thedoc]

Originally Posted by The Lone Ranger

Probably not. I did a quick, seat-of-the pants estimate, so didn't bother to do the actual calculation. A rough idea was what I was after. Given Io's apparent size from Earth with the telescopes available in Romer's time, the apparent size difference would have to be pretty big to be readily noticeable.

The difference between a dot of light and a dot of light would not be very noticeable. Would Roemer have been able to see more than that, with the telescopes of his time, I understand that he did make some very good instruments.

[The Lone Ranger]

Just so. Either way, given the telescopes available to Romer, it was simply a question of how bright the dot was. At the time of Romer's death, the largest telescope thus-far built had a 22 centimeter aperture, according to Wikipedia.

[thedoc]

Originally Posted by The Lone Ranger

Just so. Either way, given the telescopes available to Romer, it was simply a question of how bright the dot was. At the time of Romer's death, the largest telescope thus-far built had a 22 centimeter aperture, according to Wikipedia.

That is just a little larger than the reflectors I was selling to armature hobbies-ts when I had my shop. 20.3 was about the size I was selling.

[peacegirl]

Originally Posted by Dragar

You understand 'law' is a terrible word for description, right? It's an archaic throwback to how people viewed the world back in the pre-1900s.

Surely you know the area of a sphere goes as the square of the radius, right peacegirl? That's all the inverse square law is about.

I'm just wondering if it's not really a law and it was a terrible word for a description, why can't they change it to a word that's more appropriate? So how does the inverse square law rule out my question regarding size of Io? And if a human eye cannot tell the difference in size, why can't an instrument? There has to be some way to pick up on this incremental change due to the distance light has to travel. If the brightness of the dot was the only thing Roemer could see, isn't there a better way with today's technology to detect size?

[peacegirl]

Originally Posted by But

What is the apparent size here? Is it the angle subtended by its diameter in the sky?

I get something like

tan(alpha/2) = r/d

where r = Io's radius, d = its distance from Earth and alpha = its angle in the sky

so the ratio would be (alpha/alpha') = arctan(r/d) / arctan(r/d') which is approximately (d'/d) since r is small compared to d, so the angle should be about 50% larger when it's 33% closer.

Am I missing something here?

This is what I don't get. If the angle is 50% larger when it's 33% closer, wouldn't this be noticed by our telescopes today? Something doesn't add up. This is important because I want the evidence that shows a difference in size of Io due to the distance light has to travel to the observer. This difference in size would help confirm delayed vision.

[Dragar]

Originally Posted by peacegirl

I'm just wondering if it's not really a law and it was a terrible word for a description, why can't they change it to a word that's more appropriate?

Because history has a weight behind it, and sometimes we get stuck with stupid nomenclature. That's why it's important to actually read and study this stuff, rather than regurgitate the names of things from Wikipedia without actually taking time to understand it.

I'll let other people talk about Roemer, but I'm lost as to why you think it's relevant (or his original experiment). We've verified his results with much better experiments since then, and make use of the principles in modern technology. I'm also well aware that explaining things to you is an exercise in frustration.

[Vivisectus]

Originally Posted by peacegirl

This is what I don't get. If the angle is 50% larger when it's 33% closer, wouldn't this be noticed by our telescopes today? Something doesn't add up. This is important because I want the evidence that shows a difference in size of Io due to the distance light has to travel to the observer. This difference in size would help confirm delayed vision.

In what way do you figure that?