Search found 3656 matches

by PM 2Ring
Sat Jan 12, 2019 6:18 am UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 148
Views: 24968

Re: Sea level

Big G: 6.6719 * 10^-11 m^3 / s^2 kg Earth: 5.972 * 10^24 kg Product: 3.98445868 * 10^14 m^3 / s^2 It's difficult to get high precision values for the masses of astronomical bodies because it's hard to make precise measurements of big G. But we can measure orbital periods quite well, so we have good...
by PM 2Ring
Thu Jan 10, 2019 10:25 am UTC
Forum: Science
Topic: Stars in background of deep-sky photos are in foreground
Replies: 21
Views: 647

Re: Stars in background of deep-sky photos are in foreground

Eebster the Great wrote:I think his statement would be correct though if the distance to the moon were not so much greater than its diameter.

And if the Moon's orbital plane were near Earth's equatorial plane rather than being a few degrees off the ecliptic plane.
by PM 2Ring
Thu Jan 10, 2019 9:53 am UTC
Forum: Science
Topic: quarkcosh1's miscellaneous science posts
Replies: 73
Views: 5188

Re: quarkcosh1's miscellaneous science posts

BTW, if the digits of pi contain every finite sequence of digits, then pi is a normal number. That may be true, but we currently don't know how to prove that a given real number is normal.
by PM 2Ring
Tue Jan 08, 2019 1:50 pm UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 148
Views: 24968

Re: Science fleeting thoughts

(And I imagine that if you don't watch out, doubling up and doubling up a RTG either in scale or by banking more units together will start to create something that, while maybe staying subcritical by keeping spot density down, does start to go through the prompt phase, requiring extra shielding. Or...
by PM 2Ring
Mon Dec 31, 2018 1:34 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9907
Views: 1852331

Re: Coding: Fleeting Thoughts

Reading uninitialised memory is undefined behaviour, so any program that does that is already skating on very thin ice.
by PM 2Ring
Sat Dec 15, 2018 9:41 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2083: "Laptop Issues"
Replies: 27
Views: 2670

Re: 2083: "Laptop Issues"

Just occurred to me: The One Ring was a Horcrux. (Or, rather, the Horcrii/Horcruxen were as derivative of such older examples as most of the rest of the stories.) From the Science Fiction & Fantasy Stack Exchange : Tolkien took many influences from JRR Rowling - think of the Ring like a Horcrux...
by PM 2Ring
Sun Nov 11, 2018 10:58 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2070: "Trig Identities"
Replies: 18
Views: 3111

Re: 2070: "Trig Identities"

What rmsgrey said. Iterated trig functions are pretty rare, compared to powers of trig functions. I guess iterated trig functions can be used to make fractals, and of course there's the Dottie number, but there's not much practical application for them.
by PM 2Ring
Tue Oct 30, 2018 3:37 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2063: "Carnot Cycle"
Replies: 27
Views: 4864

Re: 2063: "Carnot Cycle"

And thus the Carnot cycle merges with the Pornot cycle.
by PM 2Ring
Fri Oct 19, 2018 7:23 am UTC
Forum: Coding
Topic: write a C++ please
Replies: 18
Views: 4899

Re: write a C++ please

gd1 wrote:q=(s*s)+p(s-x)*(p+y);
This is the final calculation that does some mathematics and stores the result in the variable q.

You should fix that typo. p isn't callable.
by PM 2Ring
Fri Oct 19, 2018 12:45 am UTC
Forum: Language/Linguistics
Topic: Language fleeting thoughts
Replies: 135
Views: 36145

Re: Language fleeting thoughts

In this recent Stack Exchange Physics question about a home-made cloud chamber, the OP mentioned he was using IPA, meaning isopropyl alcohol. Some readers thought he meant India Pale Ale.
by PM 2Ring
Mon Oct 15, 2018 11:47 pm UTC
Forum: Science
Topic: Why does dry ice sublimate?
Replies: 12
Views: 1962

Re: Why does dry ice sublimate?

We can look at the phase diagram of CO 2 to see how it behaves, but of course that doesn't explain why it behaves that way. Courtesy of Wikipedia (click the image for a SVG). https://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Carbon_dioxide_pressure-temperature_phase_diagram.svg/636px-Carbon_...
by PM 2Ring
Thu Sep 27, 2018 7:59 am UTC
Forum: Serious Business
Topic: Class vs class
Replies: 69
Views: 6143

Re: Class vs class

In Australia and New Zealand, the term bogan is used to refer to that class of person you're not comfortable with. I've always thought that "bogan" was the Aussie equivalent to the American "redneck", although of course there are some differences. In particular, "redneck&quo...
by PM 2Ring
Sat Sep 15, 2018 2:35 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2046: "Trum-"
Replies: 38
Views: 5755

Re: 2046: "Trum-"

I'm waiting for The Trump Show, starring Drew Carey. Or Mariah.
by PM 2Ring
Mon Sep 10, 2018 3:52 am UTC
Forum: Science
Topic: Laser recoil, relativistic momentum and whether mass counts
Replies: 4
Views: 1658

Re: Laser recoil, relativistic momentum and whether mass counts

Right, then. Momentum does not, in fact, equal mass times velocity. Wow. Thank you, chenille. Exactly. p = mv is just a Newtonian approximation. OTOH, momentum is velocity times relativistic mass, but in modern treatments of SR relativistic mass is a deprecated concept because it can be misleading,...
by PM 2Ring
Mon Sep 10, 2018 3:40 am UTC
Forum: Science
Topic: Half full or half empty?
Replies: 41
Views: 4421

Re: Half full or half empty?

But for a given volume/radius of black hole, you cannot add anything more without it becoming greater in volume/radius, so in that sense any size black hole is “full”. Sure, but that's just talking about the event horizon, which is a mathematical surface, it's not a physical object. Inside the EH, ...
by PM 2Ring
Sat Sep 08, 2018 3:31 am UTC
Forum: Computer Science
Topic: a neat picture based on recursive number
Replies: 10
Views: 2870

Re: a neat picture based on recursive number

Also see Dyck words . In the theory of formal languages of computer science, mathematics, and linguistics, a Dyck word is a balanced string of square brackets [ and ]. The set of Dyck words forms Dyck language. Dyck words and language are named after the mathematician Walther von Dyck. They have app...
by PM 2Ring
Tue Sep 04, 2018 8:28 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2040: Sibling-in-law
Replies: 52
Views: 7987

Re: 2040: Sibling-in-law

Wikipedia says The Serbo-Croatian standard languages (Croatian, Serbian, Montenegrin and Bosnian) have one of the more elaborate kinship(srodstvo) systems among European languages. [...] There are four main types of kinship in the family: biological aka blood kinship, kinship by law (in-laws), spir...
by PM 2Ring
Thu Aug 30, 2018 1:07 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2038: "Hazard Symbol"
Replies: 44
Views: 7202

Re: 2038: "Hazard Symbol"

For extra fun, make the chlorine trifluoride using 36 Cl, which is a beta emitter with a half-life of around 300,000 years, and a maximum decay energy around 709 keV. I guess you could just get some regular ClF 3 and put it inside a fission reactor to irradiate it with neutrons, but the reactor peop...
by PM 2Ring
Mon Aug 20, 2018 12:35 pm UTC
Forum: Mathematics
Topic: Cross-continuousness in higher dimensions,
Replies: 4
Views: 1463

Re: Cross-continuousness in higher dimensions,

Did someone say rhombic dodecahedron? I'm rather fond of those, as you might be able to tell from my avatar. :) The spoilered image shows the relationship between the cube, octahedron and rhombic dodecahedron (ray-traced using POV-ray). http://i2.photobucket.com/albums/y43/PM2Ring/RhombicH3S.jpg As ...
by PM 2Ring
Sun Aug 19, 2018 5:50 am UTC
Forum: Science
Topic: Gravitation 'Beach'
Replies: 11
Views: 2255

Re: Gravitation 'Beach'

Could gravitational waves not be slowed by passing through masses interacting with them, much like light itself can be slowed moving through a medium? A "gravitation beach" would then be some kind of ginormous wall of mass, somehow? I don't think so, because matter is essentially transpar...
by PM 2Ring
Tue Aug 07, 2018 1:29 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2028: "Complex Numbers"
Replies: 48
Views: 6867

Re: 2028: "Complex Numbers"

Mathematicians used negative numbers for a long while, but they weren't considered to be proper numbers. They were just a bookkeeping trick that simplified calculation and algebra. But that's what numbers are . The lot of them! Jose Well, sure. But that's a fairly modern notion, and it took a lot o...
by PM 2Ring
Tue Aug 07, 2018 1:12 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2028: "Complex Numbers"
Replies: 48
Views: 6867

Re: 2028: "Complex Numbers"

Of course, another is the idea of negative numbers. Once you have negative numbers, complex numbers are a fairly small step... Oddly enough, the historical order was the opposite of that. Mathematicians used negative numbers for a long while, but they weren't considered to be proper numbers. They w...
by PM 2Ring
Fri Jul 20, 2018 10:53 pm UTC
Forum: General
Topic: Thoughts for ships
Replies: 90075
Views: 8286100

Re: Thoughts for ships

Not dumb. Saturn does have that photoshop look to it. I've seen lots of photos of Saturn, and saw it through a cheap telescope when I was a kid, but the first time I saw Saturn through a good scope I was blown away. Modern computer enhanced imaging techniques are great, and allow us to see high qual...
by PM 2Ring
Sat Jul 14, 2018 5:10 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2019: "An Apple for a Dollar"
Replies: 80
Views: 8368

Re: 2019: "An Apple for a Dollar"

When I was there in 2002-3, Australia had abandoned anything smaller than 5c - prices were still in any integer number of cents, but, at point of sale, if paying cash, the customer got to keep the odd cents (or the shop gave a few extra cents in change) to get to a multiple of 5c. I've heard someth...
by PM 2Ring
Sun Jul 08, 2018 2:31 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2013: "Rock"
Replies: 42
Views: 6404

Re: 2013: "Rock"

Soupspoon wrote:Everything was Created on Tuesday. Even this comic, and our memories of previously having read it…

Splitter. It was last Thursday.
by PM 2Ring
Mon Jun 25, 2018 9:42 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2009: "Hertzsprung-Russell Diagram"
Replies: 35
Views: 6213

Re: 2009: "Hertzsprung-Russell Diagram"

Surely an LED bulb has a lower effective temperature than a normal (incandescent) light bulb. They have about the same surface area, but an LED bulb emits less total EM radiation. LEDs only look "hot" because their spectrum is so different to that of a black body. It seems strange to me t...
by PM 2Ring
Mon Jun 18, 2018 12:25 pm UTC
Forum: Language/Linguistics
Topic: "Cactus plant"
Replies: 20
Views: 4854

Re: "Cactus plant"

I associate "cactus plants" with the song A Fine Romance composed by Jerome Kern with lyrics by Dorothy Fields, published in 1936. The song came from the popular Fred Astaire, Ginger Rogers movie Swing Time . A fine romance, my good woman My strong, aged-in-the-wood woman You never give th...
by PM 2Ring
Mon Jun 18, 2018 11:45 am UTC
Forum: General
Topic: Questions For The World
Replies: 2216
Views: 425833

Re: Questions For The World

Not to be confused with hyphae.
by PM 2Ring
Thu Jun 14, 2018 5:21 am UTC
Forum: News & Articles
Topic: In other news... (humorous news items)
Replies: 15021
Views: 2425235

Re: In other news... (humorous news items)

FWIW, a previous discussion on solar roads is here: viewtopic.php?f=7&t=123914
by PM 2Ring
Wed Jun 13, 2018 11:03 am UTC
Forum: Individual XKCD Comic Threads
Topic: 2005: "Attention Span"
Replies: 78
Views: 9063

Re: 2005: "Attention Span"

I never encounter that "the reason being is" construction, and I really don't see why anyone would use it when they could just leave the "is" out and have something grammatically correct and shorter. E.g. "Unlike most people around here, Alice goes shopping every single day...
by PM 2Ring
Mon Jun 11, 2018 4:43 am UTC
Forum: Serious Business
Topic: Philosophy and science of gender and sex
Replies: 118
Views: 16861

Re: Philosophy and science of gender and sex

But none of that is enabled by definitions. We don't really need a precise definition of any subgroup to act appropriately towards someone we know. Well, sure. But clear agreed-upon definitions are useful if you're trying to have a technical discussion. Or if you just want to articulate your positi...
by PM 2Ring
Mon Jun 11, 2018 4:29 am UTC
Forum: Serious Business
Topic: Philosophy and science of gender and sex
Replies: 118
Views: 16861

Re: Philosophy and science of gender and sex

John Varley has several stories wherein bodies are adjustable. In one of the female protagonist first becomes male and then makes other changes. The collection is The Persistance of Vision, but I can’t remember the story title itself. The title of that particular story is Options . Several of Varle...
by PM 2Ring
Sat Jun 02, 2018 9:38 am UTC
Forum: Language/Linguistics
Topic: Language fleeting thoughts
Replies: 135
Views: 36145

Re: Language fleeting thoughts

"run through", as in "I'll run through the list", but also that thing with a sword.

Does "run by" fit the pattern?
by PM 2Ring
Sat Jun 02, 2018 6:57 am UTC
Forum: Language/Linguistics
Topic: Language fleeting thoughts
Replies: 135
Views: 36145

Re: Language fleeting thoughts

"pick down" is gibberish to me, but you could add "pick out" and "pick off". IIRC, English picked up this verb + preposition construction from the Vikings. Here's some support for that assertion Old English generally did not possess phrasal verbs as they are found in Pr...
by PM 2Ring
Sun May 06, 2018 8:10 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1989: "IMHO"
Replies: 111
Views: 17071

Re: 1989: "IMHO"

Ah yes, Jaffics Interchange Format. Giraffe-ics Interchange Format? Giraffics Interchange Format https://i.imgur.com/nCTjG87.gif Exactly. I've also heard of people pronounce JPEG as, "jay-peg," like Joint Potographic Experts Group. I thought it was Joyful Pornographic Entertainment Graphi...
by PM 2Ring
Sat Mar 31, 2018 7:40 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13412
Views: 1569310

Re: Lucky Ten Thousand (TIL)

FWIW I'm looking for something like how a person with good attention is attentive, a person with good focus is focused, a person with good dedication is dedicated, a person with good memory is... memor... able? no... iful? that's not a word... what? How about memorious? https://en.wikipedia.org/wik...
by PM 2Ring
Sat Mar 17, 2018 4:38 am UTC
Forum: Science
Topic: Quantum Question
Replies: 110
Views: 20871

Re: Quantum Question

I read an article that suggested that quantum entanglement could be explained without spooky action if causality breaks down at the quantum level - i.e. a particle sends a message back in time to its twin about how it should spin, etc. If true, IYHO would this qualify as a major revision of QM or j...
by PM 2Ring
Tue Jan 02, 2018 10:41 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1935: "2018"
Replies: 66
Views: 9035

Re: 1935: "2018"

The mean tropical year is measured at 365.24219 days, but is gradually getting smaller because the slowing of the earth's rotation is making the days longer. This means that in the long-run my system would be more accurate than either of those proposals. In discussions like this one the mean Gregor...
by PM 2Ring
Thu Nov 30, 2017 8:49 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1918: "NEXUS"
Replies: 25
Views: 4978

Re: 1918: "NEXUS"

aaronb1138 wrote:Need to find some way of getting the alt-text in the printout.

The mobile view at m.xkcd.com can display the alt text.
by PM 2Ring
Thu Oct 26, 2017 8:29 pm UTC
Forum: Mathematics
Topic: What is a Euclidean Number
Replies: 13
Views: 4400

Re: What is a Euclidean Number

They forgot to mention that the number of repetitions is supposed to be finite. Of course there are infinite sequences whose limit is a constructible number, but in general that's not the case. If you permit infinite sequences then any real number can be constructed. I was going to say something abo...

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