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### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 5:44 pm
Flemur wrote:
Sun Sep 29, 2019 4:57 pm
At 90 degrees, the top paper moves horizontally and the contact point moves at the same speed as the paper.
At 90 degrees, the crossing point will not move at all. When I finally had a nice drawing I had done it on used paper where after scanning it in the back showed through badly. Sigh. Anyway...

Let the uninterrupted blue lines show both sheets of papers at for convenience time 0. Denote angle a as depicted. At time t the top paper has moved straight up a distance Vt, the vertical red arrow, and the crossing point has moved left a distance V't, the horizontal red arrow. Now consider the width of the strip between the original top of the upper sheet of paper and the new position, as indicated in the drawing by the two densely dotted lines; let's denote it x.

First, clearly

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``````sin(a)= x / V't		iff	x = V't sin(a)
``````
Second, noting that angle a repeats at "the red angle between Vt and x",

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``````cos(a)= x / Vt		iff	x = Vt cos(a)
``````
This is hence to say that

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``````V't sin(a) = Vt cos(a)		iff	V' = V cos(a) / sin(a) = V / tan(a)
``````
[EDIT] Ah, I just now see your own edit. Your V isn't straight up! Then it makes sense and I believe yours would be right as well?

[EDIT] Yes, it definitely would; you then simply have that my "x" is Vt itself, and get `sin(a) = Vt / V't`. Quite interesting in fact, how such a detail in interpretation works out...

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 6:31 pm
rene wrote:
Sun Sep 29, 2019 5:44 pm
[EDIT] Ah, I just now see your own edit. Your V isn't straight up! Then it makes sense and I believe yours would be right as well?

[EDIT] Yes, it definitely would; you then simply have that my "x" is Vt itself, and get `sin(a) = Vt / V't`. Quite interesting in fact, how such a detail in interpretation works out...
You're right for the way I drew the picture...(I'm so rusty with photoshop I keep making mistakes), but it looks easier this way:
Phase3.png (10.36 KiB) Viewed 600 times
In a given time the contact point moves V' units horizontally while the "top paper" moves V units at angle 'a'; so for 'a' = 90, the "top paper" is moving horizontally.

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 6:36 pm
Yes. OK, settled. And to Portreve: as you see, this is in fact and at least once you got the right "picture" just high-school trigonometry; no advanced mathematics in sight yet (the Lorentz transformation of special relativity that was mentioned a bit before is...)

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 7:31 pm
Portreve wrote:
Sun Sep 29, 2019 3:19 pm
This video by vsauce seems oddly appropriate for this thread;
Now that we're done with the above interlude let me replug Portreve's link by the way. Just watched it and that's too entertaining to not be acknowledged...

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 9:01 pm
rene wrote:
Sun Sep 29, 2019 6:36 pm
Yes. OK, settled. And to Portreve: as you see, this is in fact and at least once you got the right "picture" just high-school trigonometry; no advanced mathematics in sight yet (the Lorentz transformation of special relativity that was mentioned a bit before is...)
Lol! Oh, if you only knew... heh heh heh...

I've always had math comprehension problems, going back as far as I can remember. I mean, not with knowing numbers, or doing basic math functions, but I always struggled just to get poor grades. In high school, my first year math class was General Math, and for every test I was the very last student to finish, and on several occasions I couldn't complete the test even after the period was over. The second year I took pre-algebra and failed and had to take summer school and just passed it, then took Algebra 1 and barely could hang on, even by my fingernails. My idiot guidance counselor told me just to go ahead and take Geometry anyhow, and I had to drop out at the end of the first semester because I didn't want to get another F and have to take summer school after my senior year, or stay to the next school year to take another class just to make up the overall credit requirement.

For reasons that would take too long to get into here, over the course of my life I've developed an interest in cognitive development, knowledge acquisition and dissemination methodology, and several other areas of what basically amount to psychology, and so I've always wondered whether I was developmentally delayed, or if there was some other problem. In 2009, I went to college for the first time, and of course my math skills were weak, so I had to take a remedial math class, which I did. I definitely was more able to grasp things, but what I've learned is that there comes a point for me where the layers of complexity in a math problem rapidly take me to the point where I simply lose the plot, so to speak, and I just cannot, no matter how much time and effort I put into it, comprehend the problem.

Eventually I went on to take College Algebra (essentially Algebra I and II) and I got as far as asymptotes, and I was then using like 100% effort to just barely be able to do them. Logarithms were just that bit more difficult, and no amount of office hours, remedial instruction, online aids, etc., made any difference. Fortunately I was able to pass College Algebra, but only because I had a pretty good grade average in the class: the final exam was something like 60% logarithm questions, and so I failed it. I left all those questions blank because I couldn't do any of them.

I'm not aware of any other cognitive deficits, and oddly enough I'm otherwise good at abstract reasoning.

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 9:12 pm
So, basically, the math level you guys are operating at is well beyond my capabilities. It's interesting to look at, and even have someone explain what they are trying to do (I always love behind-the-scenes type stuff) but that's all the meaning I will ever get out of it.

Fortunately for me, my areas of interest and even the thing I would love to do if I can ever afford to go back to college, have absolutely nothing to do with math.

Things being what they are in the U.S., I don't think I'll go back to college because the insane profiteering of our post-secondary system guarantees I will never be able to afford it, and alternatively, I refuse to take on the kind of financial debt so many in this country simultaneously seem unable to relate to and cannot be made to understand education is too important to be treated as a "privilege".

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 9:20 pm
rene wrote:
Sun Sep 29, 2019 6:36 pm
Yes. OK, settled. And to Portreve: as you see, this is in fact and at least once you got the right "picture" just high-school trigonometry; no advanced mathematics in sight yet
You may be able to change the position of where the laser spot will appear faster than light, but the spot won't appear until the photons reach the moon and are reflected back to you. Even if the photons are emitted from the source at a rate that exceeds light speed, those photons have to get there and back before you will see an image, which, I believe, is just a collection of photons striking your cornea.

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 9:28 pm
stormryder wrote:
Sun Sep 29, 2019 9:20 pm
You may be able to change the position of where the laser spot will appear faster than light, but the spot won't appear until the photons reach the moon and are reflected back to you. Even if the photons are emitted from the source at a rate that exceeds light speed, those photons have to get there and back before you will see an image, which, I believe, is just a collection of photons striking your cornea.
Some issues:

This only works as a hypothetical thought experiment scenario because photons emitted here on Earth by us humans do not reflect back to us from the Moon's regolith-covered surface. Period. No exceptions.

In fact, the only way we have of generating photons and getting a return is to take the biggest and most powerful ground lasers, point them at one of several highly specific spots on the Moon where we have set laser ranging retroreflectors (LRRRs), hit them with as many single-spectrum, highly specific photons as we can, and hope to get maybe 1-3 photons returned, per laser pulse, if we are lucky and aimed the thing precisely enough.

### Re: Gamma Ray Bursts From Black Holes *May* Exceed Speed Of Light

Posted: Sun Sep 29, 2019 9:44 pm
stormryder wrote:
Sun Sep 29, 2019 9:20 pm
You may be able to change the position of where the laser spot will appear faster than light, but the spot won't appear until the photons reach the moon and are reflected back to you.
That doesn't really have much to do with anything here. The point more is that "the spot" is not an object and does not move; our brain creates the illusion of movement, but what you see is different photons striking the moon at different times, not the same ones moving across the moon's surface with subluminal velocity. I.e., as per viewtopic.php?f=58&t=302499&start=40#p1693187 above.

The moon-thing we can sort of do away with here; it's a very old and well-known non-paradox..