## Search found 3685 matches

Thu May 02, 2019 11:01 am UTC
Forum: Science
Topic: Is it possible to escape from a black hole using another black hole?
Replies: 56
Views: 2207

### Re: Is it possible to escape from a black hole using another black hole?

Here are some relevant Physics Stack Exchange questions.

Black hole collision and the event horizon. The top answer there has links to several diagrams.

Why stop at lava vs ice when you can do matter vs antimatter?
What happens if you dump antimatter into a black hole?
Tue Apr 30, 2019 1:33 pm UTC
Forum: Mathematics
Topic: Analytic/ asymptotic size of rationals
Replies: 4
Views: 1128

### Re: Analytic/ asymptotic size of rationals

On a closely related note, see Farey sequence.
The Farey sequence of order n is the sequence of completely reduced fractions, either between 0 and 1, or without this restriction, which when in lowest terms have denominators less than or equal to n, arranged in order of increasing size.
Fri Apr 26, 2019 7:56 pm UTC
Topic: 2142: "Dangerous Fields"
Replies: 35
Views: 2316

### Re: 2142: "Dangerous Fields"

strix99 wrote:Well good, I was afraid I was suffering from an irrational fear of the elderly. It turns out I have a completely healthy fear of the elderly brutally beating their caregivers to death with canes and walkers.

See Hell's Grannies.
Mon Apr 22, 2019 3:27 pm UTC
Topic: 1455: "Trolley Problem"
Replies: 172
Views: 37035

### Re: 1455: "Trolley Problem"

Sat Apr 13, 2019 5:59 am UTC
Forum: Language/Linguistics
Topic: Miscellaneous language questions
Replies: 590
Views: 112178

### Re: Miscellaneous language questions

FWIW, some Anglophones quite like the sound of Dutch. But I must admit I can't tell the difference between the sound of Dutch and Afrikaans.
Sat Apr 13, 2019 4:51 am UTC
Forum: General
Topic: Thoughts for ships
Replies: 90163
Views: 8915621

### Re: Thoughts for ships

OTOH, if you average several different faces together, the resulting composite is (usually) more attractive than the originals. See examples here, and play with the interactive viewer.
Fri Apr 12, 2019 1:29 pm UTC
Forum: General
Topic: Thoughts for ships
Replies: 90163
Views: 8915621

### Re: Thoughts for ships

If you could be any startrek character from any of the tv series, which and why? I always thought the silicon-based Horta , first introduced in TOS episode The Devil in the Dark , were fascinating. But they do look rather ugly to us carbon-based life forms, so maybe I wouldn't like to actually be o...
Fri Apr 12, 2019 1:12 pm UTC
Topic: 2135: M87 Black Hole Size Comparison
Replies: 42
Views: 4006

### Re: 2135: M87 Black Hole Size Comparison

Soupspoon wrote:Incidentally, I'm sure Dr Bowman Bouman has consciously been avoiding telling us that it's full of stars…

I bet if there were a video on YouTube of Dr Katie Bouman looking at the M87* image on a computer monitor and saying "My God, it's full of stars!", it would go viral.
Thu Apr 11, 2019 4:54 pm UTC
Forum: Language/Linguistics
Topic: Miscellaneous language questions
Replies: 590
Views: 112178

### Re: Miscellaneous language questions

Another similar term we use in English (British, at least) is "brain surgery" (as something that something else is not). I can think of at least two comedy double acts that did a sketch about how an actual rocket scientist character meets (or mutually becomes aware of) an actual brain sur...
Thu Apr 11, 2019 2:24 pm UTC
Topic: 2135: M87 Black Hole Size Comparison
Replies: 42
Views: 4006

### Re: 2135: M87 Black Hole Size Comparison

From one of the best Stack Exchange Physics pages on singularities, Is a black hole singularity a single point? : A singularity in GR is like a piece that has been cut out of the manifold. It's not a point or point-set at all. Because of this, formal treatments of singularities have to do a lot of n...
Wed Apr 10, 2019 7:41 am UTC
Forum: Computer Science
Topic: Favorite Programming Language
Replies: 29
Views: 18991

### Re: Favorite Programming Language

I used to code in Advance Java during my venture in Wipro. Currently I think there are new concepts and languages like fll stack, mongo db, python and c# which are being used for developing complex projects. Are you talking about this Wipro ? BTW, Python isn't exactly new. It was conceived in the l...
Wed Apr 03, 2019 9:23 am UTC
Topic: 2131: “Emojidome”
Replies: 123
Views: 10618

### Re: 2131: “Emojidome”

The official name of the winning emoji is Milky Way. Its Unicode codepoint is U+1F30C. As well as the official name, it has several synonyms: Galaxy, Night Sky, Space, Stars, & Universe. It has over a dozen different visual representations, which you can see on Emojipedia.
Tue Apr 02, 2019 11:19 am UTC
Topic: 2131: “Emojidome”
Replies: 123
Views: 10618

### Re: 2131: “Emojidome”

AFP = alt.fan.pratchett ?
Mon Apr 01, 2019 11:41 am UTC
Topic: 2129: "1921 Fact Checker"
Replies: 49
Views: 4860

### Re: 2129: "1921 Fact Checker"

EDIT: On the note above, I assume lamp oil was edible, right? What was the property of whale oil that made it so prized for lamps over other animal fats in the 18th and early 19th centuries, and did this make it inferior as a cooking oil? Was whale oil even used in the early 1600s? The lamp oil may...
Sun Mar 31, 2019 3:08 pm UTC
Topic: 2130: "Industry Nicknames"
Replies: 28
Views: 2625

### Re: 2130: "Industry Nicknames"

Wolves have lost federal protection under the Endangered Species Act, due to the influence of Big Bad Wolf.
Sun Mar 31, 2019 3:01 pm UTC
Topic: 2129: "1921 Fact Checker"
Replies: 49
Views: 4860

### Re: 2129: "1921 Fact Checker"

I doubt that the oil was cooking oil. It was much more likely to have been lamp oil. Although olive oil has been consumed in Mediterranean regions since ancient times, Britons in the era of the Pilgrims used animal fats for cooking. The use of vegetable oil in Britain for cooking is a relatively rec...
Wed Mar 27, 2019 2:42 pm UTC
Topic: 2129: "1921 Fact Checker"
Replies: 49
Views: 4860

### Re: 2129: "1921 Fact Checker"

In British English, "corn" is a generic term for grain.
Oxford Living Dictionaries wrote:British
The chief cereal crop of a district, especially (in England) wheat or (in Scotland) oats.
Wed Mar 27, 2019 4:59 am UTC
Topic: 2128: "New Robot"
Replies: 40
Views: 3812

### Re: 2128: "New Robot"

Also see Vacuum Zeppelin.
Tue Mar 26, 2019 4:53 pm UTC
Forum: Science
Topic: Verifying physics at home
Replies: 15
Views: 1491

### Re: Verifying physics at home

"Time hacker" Tom Van Baak (& his kids) did an amateur test of gravitational time dilation using caesium atomic clocks on Mt Rainier in 2005, the 100th anniversary of Einstein's first paper on Relativity. See http://leapsecond.com/great2005 Also see Most Accurate Wristwatch  - the firs...
Sat Mar 16, 2019 12:59 am UTC
Forum: Fictional Science
Topic: A Universe that's just two massive balls... fnar
Replies: 24
Views: 1625

### Re: A Universe that's just two massive balls... fnar

They wouldn't collide at anywhere near C unless they were black holes. You could get close to c if they were neutron stars. And of course, if the combined mass & kinetic energy were high enough (after emitting some shrapnel & gravitational waves), the resulting object would very quickly col...
Sun Mar 10, 2019 11:15 am UTC
Forum: Science
Topic: Extracting energy from a black hole via gravitational blueshift
Replies: 20
Views: 1915

### Re: Extracting energy from a black hole via gravitational blueshift

Gravity is a conservative force , so the net work over a closed loop must be zero. Conservation of momentum is certainly important, but I don't think that's the solution to this puzzle, since we can make the masses of the satellites huge, so they have large momenta relative to that of the beams of l...
Sun Feb 24, 2019 3:59 am UTC
Topic: 2115: "Plutonium"
Replies: 34
Views: 5955

### Re: 2115: "Plutonium"

On the "l" vs "r" thing: even in English, the distinction isn't always clear. Eg, the "l" in "walk" & "talk" is pretty close to a (non-rhotic) "r" sound, but I expect most native English speakers don't usually notice that "l" ...
Sun Feb 24, 2019 3:50 am UTC
Topic: 2115: "Plutonium"
Replies: 34
Views: 5955

### Re: 2115: "Plutonium"

I mean it helps that plutonium is FANTASTICALLY toxic. Just like the best at making people deadsies. Bonus, even if you keep it contained, if you get enough of it together, it'll create a self sustaining pile and start their own spontaneous fissioning will irradiate you, causing you to die in extre...
Thu Feb 07, 2019 10:47 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9968
Views: 1951659

### Re: Coding: Fleeting Thoughts

Wed Feb 06, 2019 2:25 pm UTC
Forum: Mathematics
Topic: The frog riddle
Replies: 23
Views: 4087

### Re: The frog riddle

I didn't watch the video, so I'm not 100% certain of the details of this frog riddle, but it sounds like it's closely related to the Boy or Girl Paradox.
Sat Jan 26, 2019 10:27 am UTC
Forum: Science
Topic: Consequences of climate change
Replies: 90
Views: 24806

### Re: Consequences of climate change

p1t1o wrote:Sounds deep but doesnt hold water. We could easily still have capitalism with clean energy.

Indeed. Capitalism doesn't intrinsically imply that you're free to pursue your economic goals without cleaning up any messes you create in the process.
Sat Jan 26, 2019 10:20 am UTC
Topic: 2103: "Midcontinent Rift System"
Replies: 28
Views: 5179

### Re: 2103: "Midcontinent Rift System"

I'd have thought that something that split red from blue would be more popular. At least with general voters; possibly not with people who believe that their position relies on exploiting the other colour... There's a SB thread about that, although it doesn't involve an actual geophysical split. ht...
Fri Jan 25, 2019 2:12 am UTC
Forum: Language/Linguistics
Topic: Has anyone ever made a word square?
Replies: 31
Views: 12309

### Re: Has anyone ever made a word square?

I discovered EAT ATE TEA in the early 1970s. Notice that you can extend it to a cube. And a tesseract. Etc. I've done lots of 3, 4 & 5 letter word squares, and I can still do 3 letter ones from the 1st word almost instantly, but I must admit I haven't done many manually since I wrote C code to g...
Tue Jan 15, 2019 7:19 am UTC
Forum: Mathematics
Topic: Math: Fleeting Thoughts
Replies: 427
Views: 147093

### Re: Math: Fleeting Thoughts

Wikipedia has lots of info on cousin marriage, including various maps. Also see cross cousin marriage from the University of Manitoba.
Sat Jan 12, 2019 6:18 am UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 248
Views: 43368

### 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...
Thu Jan 10, 2019 10:25 am UTC
Forum: Science
Topic: Stars in background of deep-sky photos are in foreground
Replies: 21
Views: 3669

### 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.
Thu Jan 10, 2019 9:53 am UTC
Forum: Science
Topic: quarkcosh1's miscellaneous science posts
Replies: 73
Views: 11407

### 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.
Tue Jan 08, 2019 1:50 pm UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 248
Views: 43368

### 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...
Mon Dec 31, 2018 1:34 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9968
Views: 1951659

### Re: Coding: Fleeting Thoughts

Reading uninitialised memory is undefined behaviour, so any program that does that is already skating on very thin ice.
Sat Dec 15, 2018 9:41 am UTC
Topic: 2083: "Laptop Issues"
Replies: 27
Views: 5859

### 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...
Sun Nov 11, 2018 10:58 am UTC
Topic: 2070: "Trig Identities"
Replies: 18
Views: 4793

### 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.
Tue Oct 30, 2018 3:37 pm UTC
Topic: 2063: "Carnot Cycle"
Replies: 27
Views: 6272

### Re: 2063: "Carnot Cycle"

And thus the Carnot cycle merges with the Pornot cycle.
Fri Oct 19, 2018 7:23 am UTC
Forum: Coding
Replies: 18
Views: 7374

### 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.
Fri Oct 19, 2018 12:45 am UTC
Forum: Language/Linguistics
Topic: Language fleeting thoughts
Replies: 135
Views: 44813

### 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.
Mon Oct 15, 2018 11:47 pm UTC
Forum: Science
Topic: Why does dry ice sublimate?
Replies: 12
Views: 3673

### 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_...