Today I Learned

  • Thread starter Thread starter Greg Bernhardt
  • Start date Start date
Click For Summary
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.
  • #2,611
Drakkith said:
I have a few things I learned recently in Kerbal Space Program during a mission to send a bunch of probes to Jool (Jupiter analog in-game). This one is too long to post here, but I made a post on the KSP reddit page here:
For Joules and Joules... the ups and downs of my adventure to Jool

Title is a reference to Alan Shepard saying his golf ball went "miles and miles and miles" on the Moon, it obviously rhymes with Jool, and it's a reference to the fact that rockets require energy to function. Triple play!
Great story! :woot:
 
Physics news on Phys.org
  • #2,612
Today I learned that the maximum time you can possibly survive after crossing the event horizon of a non-rotating uncharged black hole is about ##15M_{BH}/M_{Sun}## microseconds. (https://arxiv.org/abs/0705.1029, equation 18).
 
Last edited:
  • #2,613
Ibix said:
Today I learned that the maximum time you can possibly survive after crossing the event horizon of a non-rotating uncharged black hole is about ##15M_{BH}/M_{Sun}## microseconds. (https://arxiv.org/abs/0705.1029, equation 18).
That's an entire minute in ours! And on whose clock?
 
  • #2,614
Ibix said:
Today I learned that the maximum time you can possibly survive after crossing the event horizon of a non-rotating uncharged black hole is about ##15M_{BH}/M_{Sun}## milliseconds. (https://arxiv.org/abs/0705.1029, equation 18).
Today (well, not exactly) I learned another rule of survival, the realistic one: Only 3 necessary "addiction elements" for all humans, and in the proper order of survival "approximate golden rule" to be followed (most of the time): "~3+ min without oxygen, ~3+ days without water, 30+ days without food ..."

[Sorry guys! This does not mention coffee, alcohol, smoking or any other addiction for that matter ... . Time to give up ... :-p:biggrin::nb)]
 
  • #2,615
Today I learned some things are just creepy...

 
Reply
  • Like
Likes Craftek_Ana, nrqed and Drakkith
  • #2,616
fresh_42 said:
That's an entire minute in ours! And on whose clock?
Hours in the largest black holes we know.
On your clock, of course.
 
  • #2,617
fresh_42 said:
That's an entire minute in ours!
By "ours", I take it you mean Sagittarius A*? Yes. Although that has spin, so this isn't strictly applicable.
fresh_42 said:
And on whose clock?
That's your own time (your so-called proper time) as you fall in, timing from when you cross the event horizon. I'm not sure there's a non-ambiguous way to talk about this period on anyone else's clock, black holes being what they are.

As noted, it's a maximum limit, and neglects the fact that you'll be torn apart by tidal forces at some point before then, even with a supermassive black hole.
 
  • #2,618
TIL that the President of Nigeria, Muhammadu Buhari, felt he had to deny that he was a human clone of himself.
There is a conspiracy theory that he had died last year and was replaced by a clone of himself (or another person from Sudan).
 
  • #2,619
CWatters said:
Today I learned some things are just creepy...



Now that is what I would call art!

When we get to a level of technology when we are able to upload consciousness, I would totally trust this artist with my 3d representation.
 
  • #2,620
Stavros Kiri said:
"~3+ min without oxygen, ~3+ days without water, 30+ days without food ..."
~3 hours without an internet connection.
 
Reply
  • Like
Likes Stavros Kiri and Drakkith
  • #2,621
DaveC426913 said:
~3 hours without an internet connection.
Why don't they just shoot us instead? ...
 
  • #2,622
Craftek_Ana said:
Now that is what I would call art!

When we get to a level of technology when we are able to upload consciousness, I would totally trust this artist with my 3d representation.
Android there we come! ...
 
  • #2,623
BillTre said:
TIL that the President of Nigeria, Muhammadu Buhari, felt he had to deny that he was a human clone of himself.
There is a conspiracy theory that he had died last year and was replaced by a clone of himself (or another person from Sudan).
Just to quash the scurrilous rumors that have been circulating in certain quarters, I too deny that I am a clone of myself...
 
Last edited:
Reply
  • Like
Likes Ibix, BillTre and Stavros Kiri
  • #2,624
Mark44 said:
Just to quash the scurrilous rumors that have been circulating in certain quarters, I too deny that I am a clone of myself...
Now that you mention it, me too!
 
Last edited by a moderator:
  • #2,625
Mark44 said:
Just to quash the scurrilous rumors that have been circulating in certain quarters, I too deny that I am a clone of myself...
I can neither confirm nor deny that I am a clone of myself.
 
Last edited by a moderator:
  • #2,626
DrGreg said:
I can neither confirm nor deny that I am a clone of myself.
Neither can I.
 
Last edited:
Reply
  • Like
Likes NTL2009, Ibix, mfb and 5 others
  • #2,627
DrGreg said:
I can neither confirm or deny that I am a clone of myself.
DrGreg said:
Neither can I.
Is that a double profile? Get him! ...
 
  • #2,628
Stavros Kiri said:
Is that a double profile?
No, single profile, with multiple personalities.
 
  • #2,629
Mark44 said:
No, single profile, with multiple personalities.
Or confused clones [using the same account] ...
 
  • #2,631
  • #2,632
Drakkith said:
for burn due to water-skis on fire.
Wood, or fiber glass?
 
Reply
  • Like
Likes Ibix, BillTre and Stavros Kiri
  • #2,633
Mark44 said:
Just to quash the scurrilous rumors that have been circulating in certain quarters, I too deny that I am a clone of myself...
The question is, what does Mark43 have to say about it?
 
Reply
  • Like
Likes mfb, BillTre, DaveC426913 and 1 other person
  • #2,634
Drakkith said:
Today I learned there is an ICD-10 code (International Statistical Classification of Diseases) for burn due to water-skis on fire.
https://www.icd10data.com/ICD10CM/Codes/V00-Y99/V90-V94/V91-/V91.07XA
See also http://www.icd10forpt.com/17-super-specific-super-bizarre-icd-10-codes/

Of note:

Z63.1 Problems with the in-laws
V97.33XD Sucked into jet engine, subsequent encounter
W56.22xA Struck by orca, initial encounter
V61.6XXD Passenger in heavy transport vehicle injured in collision with pedal cycle in traffic accident, subsequent encounter
R46.1 Bizarre personal appearance
 
  • #2,635
Bystander said:
Wood, or fiber glass?
And initial water temperature 20.435°C or 20.44°C ? These are the big issues that need to be categorized! How else one can sleep at night?
 
  • #2,636
Ibix said:
The question is, what does Mark43 have to say about it?
He's missing (broke loose)
 
  • #2,637
Ibix said:
See also http://www.icd10forpt.com/17-super-specific-super-bizarre-icd-10-codes/

Of note:

Z63.1 Problems with the in-laws
V97.33XD Sucked into jet engine, subsequent encounter
W56.22xA Struck by orca, initial encounter
V61.6XXD Passenger in heavy transport vehicle injured in collision with pedal cycle in traffic accident, subsequent encounter
R46.1 Bizarre personal appearance
BBT found an example for "We don't have a code for ..."
 
  • #2,638
fresh_42 said:
BBT found an example for "We don't have a code for ..."
Well, doesn't that have a code?
 
  • #2,639
TIL that Mars is about 3 light minutes away from us at its closest approach
 
  • #2,640
TIL what TIL means ...
 

Similar threads

Things that you regret not continuing to practice?
  • · Replies 14 ·
Replies
14
Views
2K
What Did You Learn Today? A Tradition of Daily Learning and Sharing
  • · Replies 26 ·
Replies
26
Views
6K
Home Repair & Maintenance Advice for Newbie?
  • · Replies 11 ·
Replies
11
Views
4K
Understanding the divide white/black/blue
  • · Replies 161 ·
6
Replies
161
Views
14K
Studying I feel I have lost it. How do I be dissolved in studies again?
  • · Replies 4 ·
Replies
4
Views
2K
Fighting for Financial Relief: Surviving COVID Debt
  • · Replies 9 ·
Replies
9
Views
2K
Optimizing Prisoner Strategy for the Hat Riddle: A Simple Solution
  • · Replies 35 ·
2
Replies
35
Views
7K
MHB Effective learning techniques for abstract mathematics?
  • · Replies 3 ·
Replies
3
Views
3K
My experience as a hostage
  • · Replies 2 ·
Replies
2
Views
345
Learn to Play Piano - Tips for Beginners
  • · Replies 27 ·
Replies
27
Views
6K