Today I Learned

[dkotschessaa]

Today I learned: Abstract nonsense is actual mathematics.

That I knew about.

And who bothers studying pointless topology?

That I didn't. (I realize I'm supposed to say a joke like "I don't see the point." But I won't. It would be pointless.)

-Dave K

 

[fresh_42]

And who bothers studying pointless topology?

That's for all who don't like Alexandroff extensions. (The German terms hits it better: 1-Point-Compactification.)

 

[Ibix]

And who bothers studying pointless topology?

I dunno, but I'll go out on a limb and suggest that they're strongly correlated with people who are bored of answering "so what's the point of your work? Geddit? Point?"

 

[dkotschessaa]

That's for all who don't like Alexandroff extensions. (The German terms hits it better: 1-Point-Compactification.)

How do you say that in German? (I don't imagine google translate is going to be helpful here).

 

[mfb]

Einpunkt-Kompaktifizierung?
It is a literal translation.

 

[fresh_42]

Einpunkt-Kompaktifizierung

 

[dkotschessaa]

Wow,yes, that's very literal.

 

[DrGreg]

And who bothers studying pointless topology?

Don't know who. But where? Almost nowhere?

 

[Pred]

Today I learned that studying abroad is a great way to learn new things, new culture, ideas, lifestyle as well as education system. We all know that we are living in a world with full of diverse people, and by studying abroad, we can try to experience dealing with those people and learn something from them that would help us be a better individuals and be prepared for next generation's global leaders.

 

[dkotschessaa]

Today I learned that one of the least visited national parks is Dry Tortugas National Park. 70 miles away from key west, accessible only by boat or plane, primitive camping only, and I want to go very, very badly.

 

[jim hardy]

Today I learned that one of the least visited national parks is Dry Tortugas National Park. 70 miles away from key west, accessible only by boat or plane, primitive camping only, and I want to go very, very badly.

It's way more pleasant in January.

Be sure to take enough fuel for the round trip plus a snorkeling run while you're there..
https://www.nps.gov/drto/planyourvisit/boating-sail-and-power.htm

Bringing your own boat to Dry Tortugas National Park will provide you with the most opportunities to explore this remarkable national treasure. Situated approximately 70 miles west of Key West, Florida, with no food, water, or fuel available in the park, proper planning is a must.

 

[fresh_42]

Today I learned that one of the least visited national parks is Dry Tortugas National Park. 70 miles away from key west, accessible only by boat or plane, primitive camping only, and I want to go very, very badly.

What? To visit billions of mosquitoes, pythons and alligators? Or did it get away with those invasions as an island?

 

[dkotschessaa]

It's way more pleasant in January.

Be sure to take enough fuel for the round trip plus a snorkeling run while you're there..
https://www.nps.gov/drto/planyourvisit/boating-sail-and-power.htm

I hadn't considered taking my own boat (I don't have one, but maybe by then I will?). They have a ferry you can take.

Of course yes, any outdoorsing in/around Florida I would only do in the "cold" seasons.

-Dave K

 

[OmCheeto]

Today I learned why my lettuce isn't dying, in spite of the fact that they are in a black flower pot.
Lettuce roots appear to be most comfortable at 75°F[ref], and that is their current temperature.

 

[dkotschessaa]

What? To visit billions of mosquitoes, pythons and alligators? Or did it get away with those invasions as an island?

Yes, those things are mostly on the mainland. I'm less certain about the mosquitoes, but that is why one goes in January.

-Dave K

 

[BillTre]

TIL that drones similar to those used in a Video class I took can be used to capture 3D data and make topomaps, 3D point clouds, and for making comparisons to CAD files for buildings under construction.

 

[phinds]

TIL that drones similar to those used in a Video class I took can be used to capture 3D data and make topomaps, 3D point clouds, and for making comparisons to CAD files for buildings under construction.

Jeeze, for $3,700 they better be whilstlin' Dixie while they do it !

 

[jtbell]

Today I learned that Joey Chestnut, who won the Nathan's Hot Dog Eating Contest at Coney Island today for the tenth time, doesn't just eat hot dogs. He's also won competitions in eating:

deep-fried asparagus
grilled cheese sandwiches
waffles
hamburgers
bratwurst
chicken wings
pizza
matzo balls
gyoza
macaroni and cheese
wontons
corned beef sandwiches
poutine

He's also eaten a 72-ounce steak with salad, baked potato, shrimp cocktail and roll in 8 minutes 52 seconds at a steakhouse in Amarillo, Texas.

https://en.wikipedia.org/wiki/Joey_Chestnut

The organizers of the Okra Strut Festival in Irmo SC (near Columbia) should invite him to compete in their okra-eating contest!

 

[jim hardy]

Actually it was yesterday or day before when i saw this on PBS

http://www.bbc.co.uk/programmes/articles/3t902pqt3C7nGN99hVRFc1y/which-oils-are-best-to-cook-with
Butter may not be so bad after all..

 

[mfb]

Today I learned: The easiest (!) way to express 74 as sum of three integer cubes is 74 = (−284650292555885)³ + 66229832190556³ + 283450105697727³

It is unclear if there are any solutions for 33 or 42.

 

[phinds]

Today I learned: The easiest (!) way to express 74 as sum of three integer cubes is 74 = (−284650292555885)³ + 66229832190556³ + 283450105697727³

And we have another winner of the "I've got WAY too much spare time on my hands" award

 

[mfb]

I didn't find that solution, I found a webpage discussing the general problem.

 

[Demystifier]

Today I learned that there is the list of the top 7 quirkiest physics papers with character on the arXiv, and that one of my papers is on the list:
http://www.symmetrymagazine.org/article/quirks-of-the-arxiv

 

[phinds]

Today I learned that there is the list of the top 7 quirkiest physics papers with character on the arXiv, and that one of my papers is on the list:
http://www.symmetrymagazine.org/article/quirks-of-the-arxiv

Catchy title

 

[mfb]

If "if Bohm were born before Born" implies Born was born, then the answer is clearly "yes" from a purely logical point of view.

Great title.

 

[Drakkith]

If "if Bohm were born before Born" implies Born was born, then the answer is clearly "yes" from a purely logical point of view.

Great title.

Nothing beats the abstract of the paper regarding superluminal neutrinos which just reads, "Probably not."

 

[NascentOxygen]

TIL that some uni students built a rocking chair that knits a woolen garment as you rock. "The motion of the chair starts a series of gears going that then proceed to process the spool of wool into a knit winter hat."

I guess that's a sign of the times.

http://awm.com/this-rocking-chair-knits-a-winter-hat-while-you-rock-back-and-forth/

 

[DrGreg]

TIL that some uni students built a rocking chair that knits a woolen garment as you rock. "The motion of the chair starts a series of gears going that then proceed to process the spool of wool into a knit winter hat."

I guess that's a sign of the times.

http://awm.com/this-rocking-chair-knits-a-winter-hat-while-you-rock-back-and-forth/

View attachment 207245

And if you don't like the hat, you can un-knit it with this pedal-powered un-knitting machine: http://www.designboom.com/technology/pedal-powered-un-knitting-machine-by-imogen-hedges/

 

[mfb]

Now we just need a machine that translates the rocking chair motion into rotation of the pedals, then we can knit and directly un-knit again.

Or connect it in the opposite direction and call it "re-knitting".

 

[fresh_42]

Now we just need a machine that translates the rocking chair motion into rotation of the pedals, then we can knit and directly un-knit again.

Or connect it in the opposite direction and call it "re-knitting".

Are you seriously suggest to build a perpetual motion machine here on PF? Or will your post automatically collapse if observed?

 

[mfb]

You have to rock back and forth in the chair to power the machine.

 

[Borg]

I was reading an article about a man who collected $763,000 in missing money. I followed the links and put my name in just for the heck of it. TIL that I have over $50 in unclaimed money for a previous address that I lived at.

It took a while (4 months) but I finally got my check for a little over $100 and deposited it yesterday.

 

[ElectricRay]

Today I learned that it's a Pythagorean day:

Its 8-15-17

$$17 = \sqrt{8^2 +15^2}$$

Next time will be 12-16-20 by the way.

 

[mfb]

There are just 8 triples that work (have one number <=12 and another one <=31):

3	4	5
6	8	10
5	12	13
9	12	15
8	15	17
12	16	20
7	24	25
10	24	26

After 2020, we get two in 2024, one in 2025 and one in 2026, and then the next one will be 5. April 2103.

 

[wukunlin]

I didn't know the FPU (floating point unit) used to be a chip separate from the CPU. It was like an optional add-on for users doing something mathematically intensive.
https://en.wikipedia.org/wiki/Coprocessor

 

[jim hardy]

I didn't know the FPU (floating point unit) used to be a chip separate from the CPU. It was like an optional add-on for users doing something mathematically intensive.

omg I'm getting old. I remember when the CPU was three printed circuit boards about 17 inches square populated with 7400 series IC's.
I once had to replace an accumulator , found the correct latching 4 bit register IC's at Radio Shack .

Yes - FPU is its own hardware.
In 1973 our programmer (Dr Harry) complained the FPU wasn't working.
When i looked, i found that part of the board had no IC's soldered in. FPU was an option our system guys had neglected to order so Harry had to write a software one..

old jim

 

[wukunlin]

In 1973 our programmer (Dr Harry) complained the FPU wasn't working.
When i looked, i found that part of the board had no IC's soldered in. FPU was an option our system guys had neglected to order so Harry had to write a software one..

That must have been like trying to play a modern video game without a dedicated graphics card. Sounds like a mess.

 

[Buzz Bloom]

TIL that occasionally the APOD is exceptionally artistic and beautiful.

https://apod.nasa.gov/apod/ap170830.html
​

 

[OmCheeto]

TIL that this was Phil Plait's first total eclipse.

I greatly enjoyed the last 4 paragraphs, as I concur with everything he said.

 

[Buzz Bloom]

TIL 200,000 years ago Neanderthals invented the distilling of tar to use as an adhesive.

https://arstechnica.com/science/201...tilling-tar-200-thousand-years-ago-in-europe/​

 

[fresh_42]

TIL 200,000 years ago Neanderthals invented the distilling of tar to use as an adhesive.

https://arstechnica.com/science/201...tilling-tar-200-thousand-years-ago-in-europe/​

... and we still talk about grip in vault jumping, handball or motor racing ...

 

[Bystander]

TIL https://www.cbsnews.com/news/interstellar-visitor-shaped-like-giant-pink-fire-extinguisher/

 

[nitsuj]

today i learned that there are no blue rods in the centre of our vision. normal colour vision on left, colour blind on right.

 

[fresh_42]

TIL that the long term average of IQ points (tested on Finnish recruits, and then found in the data-sets of other countries, too) has been increasing until the mid nineties and is decreasing ever since by 2 points per decade.
During my search for some quotable data (I saw it on TV, however, it was a serious channel), I found that scientists assume a correlation of those scores to the average temperature. I really wasn't expecting this as a result of CC. (The last statement is my conclusion and an exaggeration. It is not claimed by anyone. They assume a correlation based on their data of scores versus location, not CC. But a strange coincidence anyway.)

 

[Borek]

is decreasing ever since by 2 points per decade.

That explains a lot.

 

[ISamson]

Today I have learned how to analyse a film using SWAT codes and write an essay about it.

Today I have learned how to PMW on the Arduino.

 

[cosmik debris]

Today I have learned how to analyse a film using SWAT codes and write an essay about it.

Today I have learned how to PMW on the Arduino.

PWM perhaps?

 

[ISamson]

PWM perhaps?

Yep. Misspelled.

 

[Buzz Bloom]

Today I thought I learned why there are more extrinsic cancer mutations than intrinsic.
Then a bit later I learned that it might not be so.

https://www.physicsforums.com/threa...luck-or-bad-lifestyles-comments.848662/page-2
posts #21 and #22.​

 

[OCR]

Then a bit later I learned that it might not be so.

Yeah, stick with the wife... .

My wife has pointed out to me that the statistics about the number of intrinsic cancer mutations may be underestimated.