Search found 3666 matches

by PM 2Ring
Thu May 05, 2016 8:16 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1676: "Full-Width Justification"
Replies: 64
Views: 17475

Re: 1676: "Full-Width Justification"

My Linotype keyboarding manual talks quite a bit about justification. On a Linotype, automatic justification was achieved by adjusting the space between words with variable width spaces that would evenly divide up the space when the line was sent to cast. [...] ETAOIN SHRDLU Many years ago, I was g...
by PM 2Ring
Thu May 05, 2016 7:39 am UTC
Forum: Science
Topic: Dropping a Cloud Nine From Orbit
Replies: 38
Views: 6937

Re: Dropping a Cloud Nine From Orbit

Maybe I'm missing something here, but I don't see what the big problem is with just constructing the dome on the ground. Of course, it's not going to support its own weight when it's partly built, but why does it need to do that? It's a tensegrity structure, so you just build it flat, with plenty of...
by PM 2Ring
Tue May 03, 2016 7:41 am UTC
Forum: Language/Linguistics
Topic: Miscellaneous language questions
Replies: 579
Views: 103653

Re: Miscellaneous language questions

Spoiler:
Image
by PM 2Ring
Thu Apr 21, 2016 12:33 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1670: "Laws of Physics"
Replies: 46
Views: 11983

Re: 1670: "Laws of Physics"

AFAIK, Feynman did it first. "There were 183 of us freshmen, and a bowling ball hanging from the three-story ceiling to just above the floor. Feynman walked in and, without a word, grabbed the ball and backed against the wall with the ball touching his nose. He let go, and the ball swung slowly...
by PM 2Ring
Tue Apr 19, 2016 8:23 am UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13415
Views: 1643310

Re: Today I Learned

Nice round-cut diamond. Do you have Princess and Cushion cuts too? Thanks! No, I only have variations on the Tolkowsky brilliant cut. There's an old POV-Ray include file for a brilliant cut, but I wasn't happy with it, so I made an improved version by referring to Tolkowsky's book: A Study of the R...
by PM 2Ring
Mon Apr 18, 2016 8:28 am UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13415
Views: 1643310

Re: Today I Learned

... and that the LEDs on the webcam are bright enough to cause positive phototropism: http://i300.photobucket.com/albums/nn9/Sableagle/Demolition%20Ranch%20Barrett/apple_seedlings_zpsey0x1zye.gif Now trying again with a different species, from a higher angle. Interesting! I was going to ask you why...
by PM 2Ring
Mon Apr 18, 2016 8:06 am UTC
Forum: General
Topic: Origami and Mental Illness
Replies: 7
Views: 4466

Re: Origami and Mental Illness

Impressive work, Cleverbeans! FWIW, I've folded quite a few flapping birds over the decades, but never any that tiny. (But I do have a cellophane one on my desk that I folded about 20 years ago).
by PM 2Ring
Mon Apr 18, 2016 7:57 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9944
Views: 1908216

Re: Coding: Fleeting Thoughts

Everyone knows the feeling when something that should work, doesn't. Today I got to experience the more rare feeling of something working, which shouldn't. I get uncomfortable when that happens, and if I can't prove to myself why it behaves the way it does I have to change it to something I do unde...
by PM 2Ring
Mon Apr 18, 2016 7:38 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1668: "Singularity"
Replies: 26
Views: 7639

Re: 1668: "Singularity"

And for those who don't know who keithl is, please see Keith Lofstrom , Launch loop , and Keith Lofstrom's Vanity Web Page . wait. wait. ...uhh... ..uh..ok..Tell me. Is our Keith That Keith? ...Well,...ok. ... I'm willing to believe it... We are in the company of some very fine minds. He sure is. F...
by PM 2Ring
Sat Apr 16, 2016 7:31 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1666: "Brain Upload"
Replies: 38
Views: 8109

Re: 1666: "Brain Upload"

So as far as I know, we haven't covered the initial So in this forum (no doubt it's been discussed elsewhere on the board, but...). I quite like it, actually; or at least it doesn't annoy me. It seems to me that so is used in the sense "what I'm about to say follows directly from your question...
by PM 2Ring
Sat Apr 16, 2016 7:07 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1668: "Singularity"
Replies: 26
Views: 7639

Re: 1668: "Singularity"

Keyman wrote:So does the "l" in 'keithl' stand for Leibowitz?


Good call. :) For those who don't get the reference, please see A Canticle for Leibowitz.

And for those who don't know who keithl is, please see Keith Lofstrom, Launch loop, and Keith Lofstrom's Vanity Web Page.
by PM 2Ring
Mon Apr 11, 2016 6:35 am UTC
Forum: Mathematics
Topic: Simplifying expressions with unit'd values
Replies: 13
Views: 3408

Re: Simplifying expressions with unit'd values

What is the meaning of units in the denominator in this case? Can you provide an example of how this would be used and what it would translate to physically? We need ratios of lengths if we want to be able to scale things and ensure the scaled version is a similar shape ( in the sense of similar tr...
by PM 2Ring
Sat Apr 09, 2016 8:40 am UTC
Forum: Mathematics
Topic: Efficient Prizims
Replies: 9
Views: 2401

Re: Efficient Prizims

As gmalivuk said, this is easy to do if you know some calculus, but it's not too hard to verify that s=4 gives the maximum volume for the open box. To make the arithmetic simpler, I'll scale the square down by ¼, so that s=1 and the original square is 6 x 6. The base of the box has length and width ...
by PM 2Ring
Tue Mar 29, 2016 12:40 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9944
Views: 1908216

Re: Coding: Fleeting Thoughts

So there's this idea I have about tying chats/media shares like telegram, IRC and WhatsApp (using yowsup) together, but I'm unsure as to what common backend to use. The goal is to have all messages available to any networked device, though preferably messages would be loaded on demand, like a typic...
by PM 2Ring
Fri Mar 11, 2016 6:25 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1654: "Universal Install Script"
Replies: 57
Views: 20550

Re: 1654: "Universal Install Script"

INB4 : Hey this only works if you have a *nix shell running in the first place! Anyone else here old enough to have thought the pip install was referring to this? Anyway, "install" is where horses should be. I'm old enough to have used pip on CP/M, and I was certainly reminded of that pip...
by PM 2Ring
Fri Mar 11, 2016 5:50 pm UTC
Forum: Fictional Science
Topic: New (economically) type of FTL travel
Replies: 16
Views: 9501

Re: New (economically) type of FTL travel

I like it! Each ship has a accuracy parameter (usually between 1.5 and 4, unitless of type distance per distance). Travel between the source point and the actual destination is instantaneous. Specifically the traveler experiences zero/trivial time traveling and arrives at their destination either a ...
by PM 2Ring
Mon Mar 07, 2016 7:15 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9944
Views: 1908216

Re: Coding: Fleeting Thoughts

Jplus wrote:I have posted an answer too, which is a bit more efficient.


Nice approach, Julian. I didn't think of doing it like that, but I guess it works if the filtering algorithm accepts an iterator and doesn't need random access or multiple passes over the data.
by PM 2Ring
Sun Mar 06, 2016 10:45 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9944
Views: 1908216

Re: Coding: Fleeting Thoughts

I've been thinking about a SciPy-related problem I can't quite figure out yet. Since my post on Stack Overflow didn't get any replies and none of my friends appear to have a solution either, I figure it can't hurt to ask here as well. Sorry, I didn't even look at your question earlier, since I don'...
by PM 2Ring
Wed Mar 02, 2016 11:17 am UTC
Forum: Mathematics
Topic: Math: Fleeting Thoughts
Replies: 427
Views: 140095

Re: Math: Fleeting Thoughts

Here's a simple way to store a table of primes in a fairly compact form. All primes greater than 5 are obviously coprime to 2, 3, and 5 and hence are coprime to 2*3*5 = 30. IOW, all primes > 5 are congruent to one of (1, 7, 11, 13, 17, 19, 23, 29) mod 30. Note there are 8 numbers in that set, so we ...
by PM 2Ring
Sun Feb 28, 2016 2:39 pm UTC
Forum: Mathematics
Topic: Are all the sequence numbers prime?
Replies: 4
Views: 1456

Re: Are all the sequence numbers prime?

No. The next term in your sequence (after 510767) is 1380265110671180253634405030613336299264996365622991486305858014214261048243081794992210453163935138192156457386571249076356922837629566181477039018950513703169278191952771328537454016440857127805568317159302017023312808646477597452054638680664401...
by PM 2Ring
Sun Feb 21, 2016 6:34 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1643: "Degrees"
Replies: 147
Views: 24900

Re: 1643: "Degrees"

Also, for what it's worth, a black hole of one Planck mass is actually 4 Planck lengths across, ... FWIW, using 2 Planck lengths as the Schwarzschild radius and the formula for I , the entropy in bits, found in the Wikipedia article on the Bekenstein bound , the entropy of that black hole is <= 4π/...
by PM 2Ring
Fri Feb 19, 2016 5:15 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1644: "Stargazing"
Replies: 40
Views: 11184

Re: 1644: "Stargazing"

Also, does "is" imply the object's existence and status in the present tense? (So much of what we see in the sky, after all, no longer exists.) Most of the objects in our sky are within our milkyway. Those objects are, at most, about 100,000 light year away. Thus the info we have on them ...
by PM 2Ring
Wed Feb 17, 2016 3:50 am UTC
Forum: Mathematics
Topic: Infinite Inscribed Squares
Replies: 10
Views: 3079

Re: Infinite Inscribed Squares

Is that from 32 or 64 bit calculations? I'm running Python 2.6.6 on a 32 bit machine. My Python's floats are IEEE-754 doubles, so they have 53 bits of precision. The more accurate value for the area was calculated with 50 decimal digits of precision; I chopped off the last couple of digits, so the ...
by PM 2Ring
Tue Feb 16, 2016 8:30 am UTC
Forum: Mathematics
Topic: Infinite Inscribed Squares
Replies: 10
Views: 3079

Re: Infinite Inscribed Squares

Let the circle be centered at the origin, with radius 1. We'll construct the sequence of squares along the positive X axis. Let (x, y) be the coordinates of the top right corner of a square, so for each square x² + y² = 1 by Pythagoras' theorem. Let s be the side of a square. The first square has x ...
by PM 2Ring
Sun Feb 14, 2016 4:26 am UTC
Forum: Science
Topic: LIGO Gravity Waves: Questions and Answers
Replies: 49
Views: 8887

Re: LIGO Gravity Waves: Questions and Answers

Also: with detector arms in the X and y directions, a wave passing through in the z direction gives the largest signal - take a look at the GIFs on the "gravitational wave" wiki page. A wave travelling in the z direction that passes through the xy plane causes a ring of free particles in ...
by PM 2Ring
Sat Feb 13, 2016 6:28 am UTC
Forum: Science
Topic: LIGO Gravity Waves: Questions and Answers
Replies: 49
Views: 8887

Re: LIGO Gravity Waves: Questions and Answers

@p1t1o: I Am Not a Real Physicist, so I might be totally wrong, but this is my take on how LIGO works. The LIGO interferometer has two "rulers" that are perpendicular to one another. Let's call the direction of one path X and the other path Y, with Z the direction perpendicular to both X &...
by PM 2Ring
Sat Jan 30, 2016 6:04 am UTC
Forum: Mathematics
Topic: How many pencils and how many jars I have?
Replies: 7
Views: 3047

Re: How many pencils and how many jars I have?

Pity you don't have two more jars: you could put a certain number of pencils into each jar, with no pencils left over.
by PM 2Ring
Fri Jan 29, 2016 7:18 am UTC
Forum: Science
Topic: Mixing things with different melting points
Replies: 6
Views: 3824

Re: Mixing things with different melting points

Mixtures tend to have broad melting points. Waxes are generally mixtures of compounds, and even if your wax sample is supposed to be a pure compound it's likely to consist of a mixture of isomers with slightly different melting points. A conventional way of dealing with this problem when assigning a...
by PM 2Ring
Tue Jan 26, 2016 6:42 am UTC
Forum: Language/Linguistics
Topic: most words with fewest different letters
Replies: 16
Views: 8210

Re: most words with fewest different letters

There are links to various free word lists at The National Puzzlers League, but I don't know if any of them have part of speech data.
by PM 2Ring
Fri Jan 22, 2016 11:15 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9944
Views: 1908216

Re: Coding: Fleeting Thoughts

From SO Python Chat:
F4z wrote:hello, I keep getting confused with TypeError and ValueError, can someone kindly simplify for me what those two are?

bereal wrote:Ok, you go to bed and see another girl instead of your gf - that's ValueError. You see a raccoon - that's TypeError.
by PM 2Ring
Mon Jan 18, 2016 5:58 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1630: "Quadcopter"
Replies: 34
Views: 6927

Re: 1630: "Quadcopter"

I have, of course, succumbed to the law of physics stating that anyone posting a grammatical correction will make a grammatical mistake themselves. On another forum I frequent we call it the Law of Recursive Pedantry. Wikipedia says it's Muphry's Law , along with a few other terms. Also, Any correc...
by PM 2Ring
Wed Jan 13, 2016 10:34 am UTC
Forum: Science
Topic: Theory of black hole composition
Replies: 50
Views: 7268

Re: Theory of black hole composition

FWIW, the Kugelblitz blog of David Horgan has lots of info about black holes made from photons. Note that you need a very high energy density to get photons to collapse gravitationally: the photon gas needs to have a temperature greater than the Planck temperature.
by PM 2Ring
Sun Jan 03, 2016 5:13 am UTC
Forum: Mathematics
Topic: Recursive Circle Packing
Replies: 4
Views: 1562

Re: Recursive Circle Packing

Descartes theorem is useful to find the radius and location of these circles.

Image
by PM 2Ring
Mon Dec 28, 2015 8:01 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1621: "Fixion"
Replies: 19
Views: 6635

Re: 1621: "Fixion"

OP Tipping wrote:Surely 'fixion would be more appropriate at Easter.

Crucially.
by PM 2Ring
Tue Dec 22, 2015 6:13 am UTC
Forum: Science
Topic: Wendelstein 7-X
Replies: 43
Views: 8362

Re: Wendelstein 7-X

There's a lot more to plasma control than mere containment. Plasmas are tricky things. A sample of gas can (generally) be adequately modeled by the ideal gas equation, PV = nRT, where P is pressure, V is volume, T is temperature, n is the number of moles of gas, and R is the ideal gas constant . Thi...
by PM 2Ring
Tue Dec 15, 2015 6:10 am UTC
Forum: Science
Topic: Unbihexium density?
Replies: 11
Views: 3233

Re: Unbihexium density?

I don't know where you can get tungsten cylinders, but Forge Solid do tungsten cubes at a reasonable price. They also sell magnesium alloy cubes of the same size as their tungsten cubes so you can do a tangible density comparison.
by PM 2Ring
Sun Dec 13, 2015 8:15 am UTC
Forum: Science
Topic: Unbihexium density?
Replies: 11
Views: 3233

Re: Unbihexium density?

It was formerly believed that element 126 was the centre of an island stability but according to Fricke et al more recent calculations indicate that the superactinides (Z=121 to 155) are extremely unstable; see Superheavy elements a prediction of their chemical and physical properties . That article...
by PM 2Ring
Fri Dec 11, 2015 2:58 pm UTC
Forum: Science
Topic: Many, many worlds (no relation to QM)
Replies: 20
Views: 3619

Re: Many, many worlds (no relation to QM)

FWIW, there are stable multi-body orbits that don't have a central primary: one of the best-known is the beautiful figure-8 orbit, first announced by Cris Moore in 1993: http://tuvalu.santafe.edu/~moore/figure8-3.loop.gif This system is stable to minor perturbations of position and velocity, but it'...
by PM 2Ring
Sat Dec 05, 2015 1:21 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1389: "Surface Area"
Replies: 125
Views: 36264

Re: 1389: "Surface Area"

Do we not know the surface area of the solid mass at the center of Jupiter? Or is there still debate as to whether such a mass exists? (Sorry for necro -- reverse archive crawl.) We're still not sure what the center of Jupiter is like. It may have a rocky / metallic core: it's suspected that Jupite...
by PM 2Ring
Thu Dec 03, 2015 12:09 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9944
Views: 1908216

Re: Coding: Fleeting Thoughts

Understood about the Python stuff, by the way. I did only a tiny bit of perl about 8 years ago, before I had enough grounding in computer science in general to have a clue what I was doing, but the one thing I learned really well is perl regexes. I can read ridiculously long, obtuse regexes almost ...

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