Search found 179 matches

by DavidSh
Thu Jan 24, 2019 10:12 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2100: "Models of the Atom"
Replies: 34
Views: 6015

Re: 2100: "Models of the Atom"

It's fairly obviously describing the creation of the universe, under the Ptolemaic model, with the Earth at the center, surrounded by the crystalline spheres containing the seven planets (Moon, Mercury, Venus, Sun, Mars, Jupiter, and Saturn), then sphere of the fixed stars.
by DavidSh
Thu Jan 24, 2019 4:15 pm UTC
Forum: Hardware
Topic: A Question About Lens Selection and Camera Placement (Optics)
Replies: 2
Views: 1343

Re: A Question About Lens Selection and Camera Placement (Optics)

The borescope looks like a specialized version of a traditional compound microscope. There is an objective lens at the tip which casts an enlarged image, close to the eyepiece, of the object being viewed. The enlargement factor is the ratio of the distances from the objective lens to the image and t...
by DavidSh
Wed Jan 23, 2019 10:53 pm UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 267
Views: 49213

Re: Science fleeting thoughts

Maybe people differ on the definition of "electronics". For many years, it wasn't electronics if it didn't include vacuum tubes. Resisters, inductors, capacitors, batteries, and switches (like you got in an old-fashioned telegraph network) didn't count, but once you put diodes, triodes, pe...
by DavidSh
Tue Jan 22, 2019 3:36 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2101: Technical Analysis
Replies: 31
Views: 5965

Re: 2101: Technical Analysis

As stated, I would invest money into a stock, only to get the same amount of money back over time. As stated, it wouldn't even contain compensation for inflation. I think you are missing the technical definition of "present value". The present value of a payment one year from now of $1.00...
by DavidSh
Mon Jan 21, 2019 3:39 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2101: Technical Analysis
Replies: 31
Views: 5965

Re: 2101: Technical Analysis

Mouseover text in the original post should include the citation "James Tobin, July 1984". James Tobin was the 1981 Nobel Prize winner in Economics.
by DavidSh
Tue Jan 15, 2019 1:56 am UTC
Forum: Food
Topic: Today I Made:
Replies: 4751
Views: 920408

Re: Today I Made:

Concerning soba, be sure to check the ingredients list. The cheap Korean soba I usually buy contains wheat flour, besides the buckwheat flour.
by DavidSh
Mon Jan 14, 2019 5:49 pm UTC
Forum: Mathematics
Topic: Math: Fleeting Thoughts
Replies: 434
Views: 151702

Re: Math: Fleeting Thoughts

If you are talking about half-siblings, or step-sons, you get the effects Eebster the Great was discussing. If you are genetic father of a genetic full-sibling, I think you have to be your own genetic father. That's not quite as extreme as the situation of the protagonist in All You Zombies , but st...
by DavidSh
Mon Jan 14, 2019 3:56 pm UTC
Forum: Mathematics
Topic: Math: Fleeting Thoughts
Replies: 434
Views: 151702

Re: Math: Fleeting Thoughts

In any case, let's not discount any non-human entities that may work for degrees. They're worker-years. For some mathy thoughts: if you have a linear programming problem in k dimensions/properties and n variables, does your solution contain at most min{k,n} non-zero entries? In particular, I have a...
by DavidSh
Sun Jan 13, 2019 9:43 pm UTC
Forum: Language/Linguistics
Topic: Epic Shakespearian Death Monologue
Replies: 4
Views: 1655

Re: Epic Shakespearian Death Monologue

So, what help do you need?
by DavidSh
Sun Jan 13, 2019 9:38 pm UTC
Forum: Mathematics
Topic: Math: Fleeting Thoughts
Replies: 434
Views: 151702

Re: Math: Fleeting Thoughts

I think it works better as "man-years" rather than just "years". (This is the gender-free meaning of "man", just meaning a worker.)
by DavidSh
Sat Jan 12, 2019 7:00 pm UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 267
Views: 49213

Re: Science fleeting thoughts

Exoplanar mining.png The negative 270 degree temperature might be a bummer. Where are you getting that number from? What I notice is that (1) the pits seem to be of different depths, and this might mean surface air pressures are significantly different, and (2) the "ice" must be incredibl...
by DavidSh
Tue Jan 08, 2019 4:45 pm UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 267
Views: 49213

Re: Science fleeting thoughts

Another factor influencing scaling for space probes is communications. For a typical high-gain parabolic antenna, the size of the dish depends on the required gain and on the wavelength used. And, as already mentioned, the available power for communications depends on the size of the power source.
by DavidSh
Sat Jan 05, 2019 2:07 am UTC
Forum: Music
Topic: Winnie the Pooh song melody origins?
Replies: 4
Views: 2204

Re: Winnie the Pooh song melody origins?

It sort of sounds like the American tune for It Came Upon the Midnight Clear. (According to Wikipedia, there are two different tunes commonly used for this song.)
by DavidSh
Wed Jan 02, 2019 8:19 pm UTC
Forum: Science
Topic: Science fleeting thoughts
Replies: 267
Views: 49213

Re: Science fleeting thoughts

Just saw the latest press conference from the New Horizons team. It appears Ultima Thule is a contact binary. The grey-scale pictures look like a snowman, except that (1) the color images show a reddish hue, and (2) it's a lot darker than any snow I would want to be associated with.
by DavidSh
Mon Dec 31, 2018 4:02 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2949
Views: 709100

Re: Miscellaneous Science Questions

I think actual, observed physics rules this out, but nothing logically prevents this from being the year "omega + 6000", where omega is the first transfinite ordinal. ... No, I do not think that is consistent. How old would such a universe be? And what special event happened on "year...
by DavidSh
Fri Dec 28, 2018 11:48 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2949
Views: 709100

Re: Miscellaneous Science Questions

I think actual, observed physics rules this out, but nothing logically prevents this from being the year "omega + 6000", where omega is the first transfinite ordinal.

For the other view, I once had my freshman philosophy professor make the claim that tomandlu asked about.
by DavidSh
Mon Dec 24, 2018 5:48 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13421
Views: 1715378

Re: Lucky Ten Thousand (TIL)

This hydrogen maser frequency isn't in an any of the allocated frequency bands for microwave ovens; I doubt there are any ovens operating at 1.42 GHz. And figuring out the relationship between a 3d standing wave pattern in the oven cavity and wavelength isn't as easy as for a 1d oscillator. Nice vid...
by DavidSh
Mon Dec 24, 2018 5:05 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2088: "Schwarzschild's Cat"
Replies: 36
Views: 7491

Re: 2088: "Schwarzschild's Cat"

Pfhorrest wrote:
Is that not
an ocelot?

Versified that for you.

(Vaguely Ogden Nashish)
by DavidSh
Mon Dec 17, 2018 6:33 pm UTC
Forum: Mathematics
Topic: Average Difference between 2 Dice
Replies: 15
Views: 4419

Re: Average Difference between 2 Dice

jaap , you might want to check your work. A simple program like: >> M=zeros(20); >> for i=1:20 for j=1:20 M(i,j)=max(i,j); end end >> sum(sum(M))/400 gives me 13.825. And the average of the maximum of two d2s should be 1*0.25 + 2 * 0.75 = 1.75, while your formula gives (n-1)(4n-1)/6n = (1)(7)/12 = ...
by DavidSh
Sat Dec 08, 2018 8:43 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2082: "Mercator Projection"
Replies: 29
Views: 6323

Re: 2082: "Mercator Projection"

balthasar_s wrote: The planet closest to the sun? cool! :wink:
I wonder which projection is used for maps there.


NASA used a mix of Mercator for equatorial regions, Lambert Conformal for mid-latitudes, and Polar Stereographic for polar regions. Now I want a complete set of planetary and asteroidal atlases.
by DavidSh
Wed Dec 05, 2018 4:40 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2066: "Ballot Selfies"
Replies: 110
Views: 18489

Re: 2066: "Ballot Selfies"

And now we are seeing, in North Carolina, the problems with absentee ballots and people who don't follow the protocols.
by DavidSh
Wed Dec 05, 2018 4:27 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2081: Middle Latitudes
Replies: 27
Views: 5338

Re: 2081: Middle Latitudes

I think the characters are talking about places actually north of the arctic circle, such as Tromsø or Hammerfest, rather than Reykjavik. At Tromsø, the sun has been down for about a week already, and you get 5 hours of civil twilight in the middle of the day instead. --- And then at Longyearbyen, c...
by DavidSh
Sun Dec 02, 2018 4:47 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2079: "Alpha Centauri"
Replies: 32
Views: 6364

Re: 2079: Alpha Centauri

The oldest version of "all of a planet's life forming a single consciousness" I can find is Isaac Asimov's Green Patches, from 1950. The method of interconnection isn't specified there, however.
by DavidSh
Fri Nov 30, 2018 8:31 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2079: "Alpha Centauri"
Replies: 32
Views: 6364

Re: 2079: Alpha Centauri

JPL says that they expect to have to turn off the last science instrument about 2025, because of low power levels. At the moment, they each have the Cosmic Ray Subsystem, Low Energy Charged Particles, Magnetometer, Plasma Wave Subsystem instruments functioning, and Voyager 2 also has the Plasma Sci...
by DavidSh
Fri Nov 30, 2018 4:21 pm UTC
Forum: News & Articles
Topic: The Darker Side of the News
Replies: 4532
Views: 697031

Re: The Darker Side of the News

Let's see, convicted felon, registered sex offender...so is Jeffrey Epstein up for Supreme Court Justice? Or head of the Fed? Secretary of the Treasury? Secretary of Commerce? US Attorney General? (Some might object that felons can't be any of the above. Easily overcome: "Pardon.") As of ...
by DavidSh
Wed Nov 28, 2018 3:33 pm UTC
Forum: News & Articles
Topic: Trump presidency
Replies: 8644
Views: 843418

Re: Trump presidency

CorruptUser wrote:So... PBS?

Maybe they could package PBS and Voice of America into a new Department of Truth, after the fashion of the creation of the Department of Homeland Security. I think Congress would need to get involved.
by DavidSh
Fri Nov 23, 2018 5:28 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2076: "Horror Movies 2"
Replies: 41
Views: 8902

Re: 2076: "Horror Movies 2"

I hate roller coasters too, but that's mostly just because they discriminate against tall people. In what way do roller coasters descriminate against tall people? Leg room? Your head gets different accelerations from the heads of short people? What? "But why not *good* feelings?" romcoms,...
by DavidSh
Wed Nov 21, 2018 7:51 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2075: "Update Your Address"
Replies: 25
Views: 5425

Re: 2075: "Update Your Address"

I get it. You two are talking about Formosa.
by DavidSh
Wed Nov 21, 2018 7:07 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2075: "Update Your Address"
Replies: 25
Views: 5425

Re: 2075: "Update Your Address"

Eutychus wrote:There's a much simpler solution to all this: never move.

That still doesn't help if the empire you live under is dissolved.
by DavidSh
Wed Nov 21, 2018 6:55 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2073: "Kilogram"
Replies: 97
Views: 15716

Re: 2073: "Kilogram"

Correct, the raw satellite signal differences don't require a specific coordinate system. The raw satellite signals are also not GPS; GPS is a system for global positioning, which includes standards to system ically derive a position on the globe from those signals. The phrase "all four dimens...
by DavidSh
Mon Nov 19, 2018 6:02 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2073: "Kilogram"
Replies: 97
Views: 15716

Re: 2073: "Kilogram"

Good catch. It looks like the chart is wrong about it's definition of nautical miles. The nautical mile is actually actually one latitude minute (or 1 6^4 * 10 th of the way around the earth) or 6076.12 feet. Since the earth is somewhat oblate, the length of a latitude minute varies with latitude. ...
by DavidSh
Mon Nov 19, 2018 5:29 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2074: Airplanes and Spaceships
Replies: 40
Views: 7227

Re: 2074: Airplanes and Spaceships

Lockheed Martin is developing part of the Orion Multi-Purpose Crew Vehicle. Specifically, the Command Module. The Service Module is being developed by Airbus.
by DavidSh
Sat Nov 17, 2018 5:20 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2073: "Kilogram"
Replies: 97
Views: 15716

Re: 2073: "Kilogram"

Are these oz as in 1/16lb, or floz? And are floz standardized between US and imperial systems? (e.g. is a US pint exactly 4/5ths an imperial pint?) These are fluid ounces. The US fluid ounce is about 4% larger than the Imperial fluid ounce. The Imperial fluid volume system is based on the volume of...
by DavidSh
Fri Nov 16, 2018 8:50 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2073: "Kilogram"
Replies: 97
Views: 15716

Re: 2073: "Kilogram"

Indeed, what with inflation and all, I doubt you can buy beer so cheaply anywhere these days.

(Besides the question of what kind of pound, there is also the question of what kind of pint.)
by DavidSh
Thu Nov 15, 2018 9:57 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2072: "Evaluating Tech Things"
Replies: 35
Views: 7084

Re: 2072: "Evaluating Tech Things"

Researchers are flying drones into supercells. It's only a matter of time until one gets caught up in a tornado. But these aren't quadcopters, they are fixed-wing aircraft with 10 foot wingspans. This is an advertising page, but it gives the specifications.
by DavidSh
Sun Nov 11, 2018 10:33 pm UTC
Forum: Logic Puzzles
Topic: Switch
Replies: 3
Views: 1802

Re: Switch

Concerning pex 's findings, Uniqueness of the solution shouldn't be surprising. You can write the problem as a linear equation over the integers modulo 2, in matrix form Ax=b, where x indicates the buttons you push, b is the vector of all ones, and A is a matrix where each row corresponds to the...
by DavidSh
Thu Nov 01, 2018 9:17 pm UTC
Forum: News & Articles
Topic: Where Aren't They Now (Obituaries)
Replies: 337
Views: 106147

Re: Where Aren't They Now (Obituaries)

If we are doing obits for robotic space probes, the asteroid probe Dawn has lost contact . Its last reaction wheel failed some time ago, and it is presumed to have now run out of hydrazine, and be unable to point its antenna at Earth. In an earlier blog post , JPL describe in heart-breaking detail w...
by DavidSh
Thu Nov 01, 2018 12:31 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2066: "Ballot Selfies"
Replies: 110
Views: 18489

Re: 2066: "Ballot Selfies"

Furthermore, without major restructuring of elections, they'd have to offer from potentially tens of thousands of different ballots. My ballot for the coming election includes both senators and local school board members. There is no single national ballot. Even just for the presidential election, d...
by DavidSh
Wed Oct 31, 2018 3:56 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2066: "Ballot Selfies"
Replies: 110
Views: 18489

Re: 2066: "Ballot Selfies"

If you can prove to people how you voted, you can more easily sell your vote. Similarly, other people can pressure you into voting a certain way, and into using a ballot selfie to prove you were compliant.

As it is now, no one can expect you to back up any claim you make about your vote.
by DavidSh
Tue Oct 30, 2018 3:20 pm UTC
Forum: Fictional Science
Topic: Asimov's 3 laws
Replies: 17
Views: 6114

Re: Asimov's 3 laws

I don't know if this is an Asimov short story or just an Asimovesque one, but there's on tale where a robot crew descend to meet a ?Jovian? civilisation, who they accidentally astound by their high resilence ('leaky' spaceship, because anything else would crush or explode from space/gas-giant press...

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