Today I Learned

[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.

 

[fresh_42]

Yeah, stick with the wife... .

One of these mysteries in the universe: they are always right and we have absolutely no clue how they manage it.

 

[OCR]

One of these mysteries in the universe: they are always right and we have absolutely no clue how they manage it.

That's one of the major unsolved problems that is theoretical... meaning, that existing theories seem incapable of explaining a certain observed phenomenon or experimental result.

 

[mfb]

Today I learned about lithium fluorine (+hydrogen) as rocket propellant.
It has a higher specific impulse (exhaust velocity) than all other tested chemical propellants, even higher than hydrogen+oxygen. It has some minor disadvantages, however:

- It needs liquid fluorine, at a temperature below -188 °C (85 K, -307 °F) to prevent boiling.
- It needs liquid lithium, at a temperature above 180 °C (453 K, 356 °F) to prevent freezing.
- It needs liquid hydrogen, at a temperature below -252 °C (21 K, -423 °F) to prevent boiling.
- Liquid fluorine is extremely corrosive and reacts with nearly everything.
- Liquid lithium is extremely corrosive and reacts with a lot of stuff, including spontaneous ignition when in contact with air, water or organic substances
- Liquid hydrogen, when in contact with air and a flame, can explode.
- Fluorine will spontaneously react with both hydrogen and lithium, and lithium and hydrogen together will also react (but slower).
- Fluorine is toxic.
- Hydrogen fluoride is toxic and part of the exhaust stream.
- All three propellants must be combined in a suitable ratio at the same time for a proper reaction.

It has been https://www.flightglobal.com/pdfarchive/view/1967/1967%20-%200069.html, but then it was considered to be too impractical for rockets.

 

[yecko]

Today, I've learned the reason why does a comet's tail always face away from the sun.
Comet is made up of a nucleus (solid, frozen ice, gas and dust), a gaseous coma (water vapor, CO2, and other gases) and a long tail (made of dust and ionized gases). The tail develops when the comet is near the Sun. Its long ion tail of always points away from the sun, because of the force of the solar wind.
http://www.enchantedlearning.com/subjects/astronomy/comet/

 

[Grands]

Today I learned that everyday a lots of people die because there are economical interests, which for some riches are more important then life.

 

[stephenkohnle53]

Today I learned that mercury is not nearly as dangerous as many people think, although it still is dangerous

 

[Best Pokemon]

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.)

Warm weather makes it harder to think: https://www.scientificamerican.com/article/warm-weather-makes-it-hard-think-straight/

 

[BillTre]

TIL that this exists:

 

[AbstractlyAlgebraic]

Today I learned that I really don't want to go to graduate school in math anymore. It just don't like it as much as I thought I did.

 

[OmCheeto]

TIL that a packet of "Top Ramen" is supposed to feed two people.

It's no wonder I'm so fat.