Today I Learned

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Today I learned that cleaning a white hat can be done with bleach cleaner, but it’s important to rinse it before wearing it again. I also discovered that "oyster veneering," a woodworking technique from the late 1600s, is experiencing a minor revival despite its labor-intensive nature. Additionally, I learned that the factorial of 23 (23!) equals 25,852,016,738,884,976,640,000, which interestingly has 23 digits, a unique coincidence among factorials. I found out that medical specialists often spend less than 10 minutes with patients, and that watching TV can contribute to weight gain. Other insights included the fact that a kiss can transfer around 80 million microbes, and that bureaucracy can sometimes hinder employment opportunities. The discussion also touched on various trivia, such as the emotional sensitivity of barn owls and the complexities of gravitational lensing around black holes.
  • #2,491
No. My intention was post # 2489.

Regards,
Buzz
 
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  • #2,492
Buzz Bloom said:
The rule of thumb I have learned is to keep about three seconds behind the car in front of me.
That would had given me 130 meters. Probably around the distance which I actually needed. Our rule of thumb is half the speedometer (in km/h). That would have given me 80 meters, which I think hadn't been enough. Anyway, the main experience was, that kinetic energy counts, and this is quadratic in speed, so what works for low speeds doesn't necessarily work at higher speeds. And all three rules so far are linear in speed!
 
  • #2,493
fresh_42 said:
Anyway, the main experience was, that kinetic energy counts, and this is quadratic in speed, so what works for low speeds doesn't necessarily work at higher speeds. And all three rules so far are linear in speed!

Disappointing.
I thought you were going relativistic.
 
  • #2,494
Drakkith said:
there's a real delay between receiving signals, processing them, and then acting on them that your brain has to take into account or else you smash into a pole or person coming around a corner or something.

I wonder what part of the brain does that. I marvel watching a hawk or hummingbird navigate through tree limbs. I can't even think that fast.
 
  • #2,495
nitsuj said:
Such a subtle thing that when and where it counts, shows a vast difference in abilities; between me and some pro athlete lol
gleem said:
The more you practice the more an action becomes a reflex not requiring nearly as much processing time An athlete also need a good sense of anticipation of his opponent's next move. It is easier to fake out an amateur.

Anyone can train like a "pro athlete".

Almost implicitly some variations of our genetics are better at such brain/nervous system tasks than others...Ask Michael Jordan lol
 
  • #2,498
Drakkith said:
I've always wondered how much of your brain's 'processing power' goes into predicting the near future. Not in a tarot card, palm reading, or other magical sense, but in the sense that there's a real delay between receiving signals, processing them, and then acting on them that your brain has to take into account or else you smash into a pole or person coming around a corner or something.

On a somewhat related note (sort of related, or at least sort of in-part), this new Physics Girl episode just came out today:
 
  • #2,499
Drakkith said:
I've always wondered how much of your brain's 'processing power' goes into predicting the near future. Not in a tarot card, palm reading, or other magical sense, but in the sense that there's a real delay between receiving signals, processing them, and then acting on them that your brain has to take into account or else you smash into a pole or person coming around a corner or something.
Speaking of sight, I've always been interested in eye movement. You never ever see the wooshing eye movement when you move your eyes from one area to another. Your brain just stops formulating and constructing the world for a few milliseconds and just cuts off perception until your eyes have stopped moving. What does your evolution programming do to create continuity in experience? It slows down your perception of time passing to aid in you thinking that your visual feed was never cut off at all, because no time has passed since you were last seeing input.

https://en.wikipedia.org/wiki/Time_perception#Eye_movements_and_"Chronostasis"
 
  • #2,500
TheDemx27 said:
Speaking of sight, I've always been interested in eye movement. You never ever see the wooshing eye movement when you move your eyes from one area to another. Your brain just stops formulating and constructing the world for a few milliseconds and just cuts off perception until your eyes have stopped moving.

You sure about that? I swear I can see a small amount of blur or 'whoosh' when quickly looking back and forth.
 
  • #2,502
Currently reading Peter Lynch's, One Up on Wall St., and learned that the bear market of the early 1970's took 15 years for the Dow and other averages to regain the prices reached in the mid-60's.

Dang...15 years!

Talk about needing patience to hold onto stocks!
 
  • #2,503
TheDemx27 said:
You never ever see the wooshing eye movement when you move your eyes from one area to another. Your brain just stops formulating and constructing the world for a few milliseconds and just cuts off perception until your eyes have stopped moving.

When driving at night i am bothered by modern luxury automobile taillights that are pwm LED's . When i move my eyes i see a series of dots and it's really disturbing.

Check it yourself next time you're behind a Cadillac or Lexus .

i'd say perception doesn't stop it's just dulled.

old jim
 
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  • #2,504
I think the retina also has what is called persistence. i.e, the response to light does not decrease instantaneously to zero when the stimulus is remove. so a moving bright light will appear as a streak in your vision. The brain has to process the changing signal as well as it can and sometimes it doesn't get it right. Witnesses to accidents often do not agree with one another.
 
  • #2,505
jim hardy said:
When driving at night i am bothered by modern luxury automobile taillights that are pwm LED's . When i move my eyes i see a series of dots and it's really disturbing.

Check it yourself next time you're behind a Cadillac or Lexus .

i'd say perception doesn't stop it's just dulled.

old jim
I agree,

I was watching a stream of stones being flung from a conveyor and was "playing" with following the stones visually. It was fun to see the stream of stones go from a blur, to seeing individual stones if I followed them visually.
 
  • #2,506
TIL that the rate of applications for naturalization increased by 1200% since Brexit. (Has been named as a cause for the increasing number of double citizenships.)
 
  • #2,507
In which country from which country?
 
  • #2,508
mfb said:
In which country from which country?
From UK to Germany. As they keep their passport, a second one simply enlarges their options. Would be interesting to know how the British tax laws are, because Americans wouldn't have this option if they don't want to get taxed twice, as the US taxes by citizenship and not by location.
 
  • #2,509
British and European taxes are generally similar with different rates and allowances/deductibles. Some tax on where you are 'ordinarily resident' which isn't always the same as where you are living. This can sometimes mean you are you are taxed twice but we have double taxation treaties. Not all EU countries have Capital Gains tax so it may pay to realize gains before/after emigrating. Should always take tax advice before emigrating or it can cost you big time.
 
  • #2,510
Today I learned that, fully fueled and loaded, the Saturn V launch vehicle + Apollo spacecraft had a mass of nearly 3 MILLION kg! Each of the five F-1 engines on the 1st stage burned just over 2500 kg of fuel and oxidizer each second, pushing a combined total of 12,890 kg of mass out the back and propelling the vehicle with 35 MN of force! (that's MN for mega-Newtons. Yes, MEGA Newtons! Not your ordinary Isaac Newtons, but Isaac with his superhero pants on!) For those here in the states, that's 7.891 million pounds of thrust.

It sure beats the fins off of my 20 oz model rocket I had as a kid!
 
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  • #2,511
Drakkith said:
pushing a combined total of 12,890 kg of mass out the back and propelling the vehicle with 35 MN of force!
48 GW of power, about 10 GW per engine.

Each F-1 had a fuel pump with a power of 40 MW.
 
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  • #2,512
No chlorine in RP1.
Shuttle boosters had solid fuel, aluminum with polyvinyl chloride binder and ammonium perchlorate oxidizers -

and they complain about chlorine from car air conditioners ?:wink:
 
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  • #2,513
mfb said:
48 GW of power, about 10 GW per engine.

Each F-1 had a fuel pump with a power of 40 MW.

Speaking of power, I just launched my first Saturn V in Kerbal Space Program (with a realism mod added) and my S-IVB stage had exactly zero power. Because I forgot to add fuel to the fuel tank. (I blame the ground crew. The sign said "Full Service". At least it will once I get back!) Luckily it was an Apollo 8 style mission with no LM and I still had enough delta-v to get to the Moon and back.

Interestingly my orbital velocity around the Earth was only around 200 m/s after my TEI (trans-earth injection, the engine burn to get out of the Moon's orbit and back to Earth's), while my orbital velocity around the Moon was somewhere between 1k and 2k m/s. Nothing like trying to understand linear velocities along curved paths while transitioning between moving reference frames in three dimensions to get the brain juices flowing!
 
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  • #2,514
Today I learned how to identify the back locust tree. This came shortly after I learned that the black locust has thorns.
 
  • #2,515
Fewmet said:
Today I learned how to identify the back locust tree. This came shortly after I learned that the black locust has thorns.
And did you learn that the hard way ? :smile:
 
  • #2,516
Today I realized that a guy, Shaun, who I deal with occasionally and who recovers tissues from deceased donors for transplanting, is...

Shaun of the Dead!
 
  • #2,517
Today...a few days ago, actually...I learned that the capital of Turkey is *not* Istanbul. I had been living a lie for the past 19-20 years.
 
  • #2,518
Fewmet said:
Today I learned how to identify the back locust tree. This came shortly after I learned that the black locust has thorns.
Yep they'll go clear through a boot or tractor tire.
 
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  • #2,519
Just now I learned that the melody for "God Save the King/Queen", which is used on this side of the pond for "My Country 'Tis of Thee", was used at George Washington's inauguration in 1789, 33 years before the latter song was written. On that occasion the words were:

Hail, thou auspicious day!
For let America
Thy praise resound.
Joy to our native land!
Let every heart expand,
For Washington's at hand,
With glory crowned.


I wonder if the choice of melody was politically deliberate. :cool:

Was God Save the Queen played at John McCain's funeral? (BBC News)
 
  • #2,520
Wiki says the melody for God save the Queen has been first published in 1744 with similar even older melodies. So the winner are the British in this case. Surprisingly "The Jacobites also adopted the song with the introductory words "God save great James our king" ". Seems it served each side even before Washington.
 

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