Today I Learned

  • Thread starter Greg Bernhardt
  • Start date
In summary: Today I learned that Lagrange was Italian and that he lamented the execution of Lavoisier in France during the French Revolution with the quote:"It took them only an instant to cut off this head and a hundred years might not suffice to reproduce it's...brains."
  • #4,236
Interesting. What happened?
 
Physics news on Phys.org
  • #4,237
Keith_McClary said:
TIL: Don't try to make cowboy coffee in the microwave.
Guessing you mean 'boiled coffee', with the grounds in the cold water?
berkeman said:
Interesting. What happened?
Guess 2: Keith cleaned microwave.
 
  • Like
  • Haha
Likes hutchphd, gmax137 and pinball1970
  • #4,238
Klystron said:
Guessing you mean 'boiled coffee', with the grounds in the cold water?
I should at least have used a larger container. And it probably didn't help that it was fresh ground, with a pretty good "bloom".
 
  • Like
Likes Klystron
  • #4,239
Keith_McClary said:
I should at least have used a larger container. And it probably didn't help that it was fresh ground, with a pretty good "bloom".
Lots of good nucleation centers
 
  • #4,240
  • #4,241
Interesting... kind'a. I read the link and my impression was:

  • Module 1: Set the hook (to sign up)
  • Modules 2 - 6: How to be a salesman
  • Modules 7 - 8, & unit 1 of Module 9: Potentially useful info for a new retiree
  • Module 9, unit 2: How to do the above better
  • Module 9, unit 3: How to start a business

(There is a bridge in New York City for sale, are you interested?)

Oh well...
 
  • #4,242
Having spent much of my adult life freelancing I think being a certified professional retirement coach is my perfect next gig. I need to
  1. set up my certification company
  2. pass my own stringent certification test
  3. hang out my shingle
OK maybe tomorrow...(I'm already am good at this)
 
  • Haha
Likes jtbell, DaveE and Klystron
  • #4,243
hutchphd said:
pass my own stringent certification test
Not so fast?:
7bfd14407c99013a9ba3005056a9545d.gif

Dilbert
 
  • Like
  • Haha
Likes Astronuc, mfb and hutchphd
  • #4,244
jtbell said:
Today I learned that certified professional retirement coaches are a thing, for people who don't know what they're going to do after they no longer have to go to the office (or Zoom to it) every day.
Overheard at a gunshow: A, "How's retirement going?"; B, "I'm going to have to go back to work so I can have some time for myself."
 
  • Like
Likes phinds, diogenesNY and BillTre
  • #4,245
I'm retired now and it is keeping me surprisingly busy.
 
  • Like
  • Haha
Likes Astronuc, Oldman too and collinsmark
  • #4,247
  • Like
Likes phinds and Oldman too
  • #4,248
TIL that Mho's, a unit of electrical conductance, is just Ohm spelled backwards.
It also uses an upside down omega as its symbol, whereas Ohm's uses a non-inverted omega.
Conductance is also the reciprocal of resistance.
They just took everything about Ohm's and inverted them!
 
  • Like
  • Informative
Likes collinsmark, Klystron, BillTre and 1 other person
  • #4,249
TIL the title of the PF science fiction subforum is "Writing and Worldbuilding". I read the title as "Word Building", improving vocabulary. Several confused would-be authors must be wondering why I offer terms such as 'tantalus' and 'antidisestablishmentarianism' when they are trying to introduce hubris in their conquerors or, latter term, imposing worldwide religions in their text.

Perhaps worthy of a simpler story, my eyeballs were zapped by concentrated sunlight when I refused to relinquish visual lock on fighter planes flying into the sun, not to mention laser beams frying my cornea while my crew rushed to engage clunky mechanical shields on old optics. Ouch. So, "floaters" often obscure skinny characters such as 'l'.
 
  • Like
  • Haha
Likes hutchphd, DaveC426913 and BillTre
  • #4,250
Klystron said:
TIL the title of the PF science fiction subforum is "Writing and Worldbuilding". I read the title as "Word Building", improving vocabulary. Several confused would-be authors must be wondering why I offer terms such as 'tantalus' and 'antidisestablishmentarianism' when they are trying to introduce hubris in their conquerors or, latter term, imposing worldwide religions in their text.

Perhaps worthy of a simpler story, my eyeballs were zapped by concentrated sunlight when I refused to relinquish visual lock on fighter planes flying into the sun, not to mention laser beams frying my cornea while my crew rushed to engage clunky mechanical shields on old optics. Ouch. So, "floaters" often obscure skinny characters such as 'l'.
I still read it as Word building.
 
  • Like
Likes Klystron and BillTre
  • #4,251
Drakkith said:
They just took everything about Ohm's and inverted them!
...that reminds me of how, as a child, I thought "impedance" was pronounced with emphasis on the "Im". Years later, when I said it aloud in a physics lab, I wondered why the tutor laughed...
 
  • Like
  • Haha
  • Informative
Likes Oldman too, Drakkith and Tom.G
  • #4,252
Klystron said:
I read the title as "Word Building", improving vocabulary.
Well, that's definitely part of the work. There is no good technobabble without a good set of new almost-meaningful words o0)

So 'word building' definitely should be part of every curriculum about writing sci-fi :wink:
 
  • Like
Likes Klystron
  • #4,253
TIL, that the magnitude of an Earthquake is not based on its severity - it is based on the length of the fault.

The largest earthquake in recorded history - a 9.5 - occurred in Valdivia, Chile, in 1960. It spanned one thousand miles.

The reason a Mag 10 quake cannot happen is because there are no faults anywhere in Earth sufficiently long - it would have to span a significant portion of the Earth's circumference.
 
  • Informative
  • Like
Likes hmmm27, Oldman too, strangerep and 1 other person
  • #4,254
DaveC426913 said:
TIL, that the magnitude of an Earthquake is not based on its severity - it is based on the length of the fault.

The largest earthquake in recorded history - a 9.5 - occurred in Valdivia, Chile, in 1960. It spanned one thousand miles.

The reason a Mag 10 quake cannot happen is because there are no faults anywhere in Earth sufficiently long - it would have to span a significant portion of the Earth's circumference.
Source? I think somebody is pulling your leg...
 
  • Like
  • Informative
Likes phinds, Oldman too and Klystron
  • #4,255
berkeman said:
Source? I think somebody is pulling your leg...
Length of faults certainly a factor but quake magnitude involves a logarithmic scale measuring energy release. Earth science not my area, but grew up in California quake country.

https://en.wikipedia.org/wiki/Earthquake#Intensity_of_earth_quaking_and_magnitude_of_earthquakes

...Only in the last century has the source of such shaking been identified as ruptures in the Earth's crust, with the intensity of shaking at any locality dependent not only on the local ground conditions but also on the strength or magnitude of the rupture, and on its distance.[33]

The first scale for measuring earthquake magnitudes was developed by Charles F. Richter in 1935. Subsequent scales (see seismic magnitude scales) have retained a key feature, where each unit represents a ten-fold difference in the amplitude of the ground shaking and a 32-fold difference in energy. ... bolding added

Although the mass media commonly reports earthquake magnitudes as "Richter magnitude" or "Richter scale", standard practice by most seismological authorities is to express an earthquake's strength on the moment magnitude scale, which is based on the actual energy released by an earthquake.
 
  • Informative
  • Like
Likes phinds, mfb, Oldman too and 1 other person
  • #4,256
TIL, GORT (yes that one) is an acronym for Genetically Organized Robotic Technology, pretty cool for '50's Sci Fi.
 
  • Like
Likes fresh_42 and Klystron
  • #4,257
Oldman too said:
Genetically Organized Robotic Technology
And I thought those were Borg.
 
  • Like
  • Haha
Likes Keith_McClary, Borg and Oldman too
  • #4,258
fresh_42 said:
And I thought those were Borg.
I'm working out the acronym for that...
 
  • Like
Likes fresh_42
  • #4,259
Oldman too said:
I'm working out the acronym for that...
Not a trekkie myself, but my youngest sister definitely fills that bill. When Jean Luc was first assimilated, I figured Borg was short for cyborg, cybernetic organism, since they merged humans with computer machinery. Battlestar Gallactica, popular at the time, featured Cylons, so sis figured Trek NG writers dropped the 'cy-' to avoid comparisons and sound edgier.

Borg. Resistance is futile.​
 
  • Like
Likes Oldman too and Drakkith
  • #4,260
The name of the Borg Seven of Nine may have been inspired by Ernest Borgnine.
 
  • Wow
  • Like
  • Informative
Likes hmmm27, Klystron and Oldman too
  • #4,261
strangerep said:
...that reminds me of how, as a child, I thought "impedance" was pronounced with emphasis on the "Im". Years later, when I said it aloud in a physics lab, I wondered why the tutor laughed...
In English English it is.
I can only guess why your tutor laughed, maybe it sounded like impudence?
Where is the rule that says one or the other in both cases?
Don't think there is a universal authority for them.
 
  • #4,262
Drakkith said:
TIL that Mho's, a unit of electrical conductance, is just Ohm spelled backwards.
It also uses an upside down omega as its symbol, whereas Ohm's uses a non-inverted omega.
Conductance is also the reciprocal of resistance.
They just took everything about Ohm's and inverted them!
I always thought that was very clever, and it made me chuckle a bit, something needed in the often strict world of science/engineering. Unfortunately, the 14th General Conference on Weights and Measures lacked any sense of whimsy or humor. They officially replaced the Mho with siemens. Which is confusing, S for siemens, and we already have s for seconds. mS or ms?

https://en.wikipedia.org/wiki/Siemens_(unit)
The 14th General Conference on Weights and Measures approved the addition of the siemens as a derived unit in 1971.[1]

Along those lines, I was disappointed to learn that the word for "palindrome" in
Esperanto is not spelled the same backwards and forwards. What a missed opportunity!

palindrome Esperanto: palindromo
 
  • Like
Likes Klystron
  • #4,263
berkeman said:
Source? I think somebody is pulling your leg...
United States Geological Survey?
https://www.usgs.gov

Klystron said:
Length of faults certainly a factor but quake magnitude involves a logarithmic scale measuring energy release. Earth science not my area, but grew up in California quake country.

https://en.wikipedia.org/wiki/Earthquake#Intensity_of_earth_quaking_and_magnitude_of_earthquakes

"The magnitude of an earthquake is related to the length of the fault on which it occurs. That is, the longer the fault, the larger the earthquake. ... No fault long enough to generate a magnitude 10 earthquake is known to exist, and if it did, it would extend around most of the planet."
https://www.usgs.gov/faqs/can-megaquakes-really-happen-magnitude-10-or-larger
 
  • #4,264
DaveC426913 said:
United States Geological Survey?
https://www.usgs.gov
DaveC426913 said:
"The magnitude of an earthquake is related to the length of the fault on which it occurs. That is, the longer the fault, the larger the earthquake.
Oh, that's different from what you said originally, IMO. Sure, the longer fault line will store more energy, all else being equal. But the magnitude of the earthquake is based on the energy released.

You originally said:
DaveC426913 said:
TIL, that the magnitude of an Earthquake is not based on its severity - it is based on the length of the fault.

That's what confused me. :smile:
 
  • Like
Likes phinds, Klystron and fresh_42
  • #4,265
berkeman said:
Oh, that's different from what you said originally, IMO. Sure, the longer fault line will store more energy, all else being equal. But the magnitude of the earthquake is based on the energy released.

You originally said:That's what confused me. :smile:
I'm afraid I am simply quoting from the government."The magnitude of an earthquake is related to the area of the fault on which it occurs - the larger the fault area, the larger the earthquake. The San Andreas Fault is 800 miles long and only about 10-12 miles deep, so that earthquakes larger than magnitude 8.3 are extremely unlikely.

The largest earthquake ever recorded by seismic instruments anywhere on the Earth was a magnitude 9.5 earthquake in Chile on May 22, 1960. That earthquake occurred on a fault that is almost 1,000 miles long and 150 miles wide, dipping into the Earth at a shallow angle. The magnitude scale is open-ended, meaning that scientists have not put a limit on how large an earthquake could be, but there is a limit just from the size of the earth. A magnitude 12 earthquake would require a fault larger than the Earth itself."I mentions nothing about the amount of energy released.
 
  • #4,266
DaveC426913 said:
I mentions nothing about the amount of energy released.

https://pubs.usgs.gov/gip/earthq4/severitygip.html
The Severity of an Earthquake

The severity of an earthquake can be expressed in terms of both intensity and magnitude. However, the two terms are quite different, and they are often confused.

Intensity is based on the observed effects of ground shaking on people, buildings, and natural features. It varies from place to place within the disturbed region depending on the location of the observer with respect to the earthquake epicenter.

Magnitude is related to the amount of seismic energy released at the hypocenter of the earthquake. It is based on the amplitude of the earthquake waves recorded on instruments which have a common calibration. The magnitude of an earthquake is thus represented by a single, instrumentally determined value.
 
  • Informative
  • Like
Likes mfb, Tom.G and Klystron
  • #4,267
It would be nice if the government got its act together and defined its terms unambiguously. They appear to say two different things, both of which appear equally valid.
 
  • #4,268
It is complicated. E.g. TIL that the Richter scale is a) empirical, b) only valid in a certain range of amplitudes, c) only for Wood-Anderson seismographs, and d) meant to be applied in Southern California only.

Lecture Notes ETH Zurich p.7 and 19-20 said:
Earthquakes come in all sizes: seismometers in mines record micro-ruptures a few tens of centimeters in length, which correspond to negative magnitudes. A magnitude ##2## tremor can be felt close at the hypocentre, which is roughly the length of a rupture of a few tens of meters, a medium-sized earthquake breaks several tens of kilometers of a fault, while in large earthquakes such as the ##1906## ##M7.8## San Francisco Tremors on the San Andreas Fault, breaking several hundred kilometers at a time.
...
A quantity can also be derived from the seismograms recorded at the various stations, which is a measure of the energy radiated by an earthquake. This quantity is called magnitude, which is a logarithmic one and corresponds to the energy scale.
...
Over time, a variety of synonymous local and global magnitude definitions based on amplitudes of different seismic wave types have been developed and devices introduced. They are scaled so that they end up having similar numerical values. They fulfill the general form:
$$
M=\log_{10} \left(\dfrac{A}{T}\right)+Q(r,h)+a
$$
where ##A## is the measured amplitude in the seismogram, ##T## the corresponding time period,
##Q(r,h)## is a correction term that depends on the distance ##r## and the depth of the focus ##h##, and ##a## is an empirical constant.
...
However, this type of magnitude indication does not contain any direct information about the total energy of an earthquake, but only about the energy radiated in a certain frequency range.
https://ethz.ch/content/dam/ethz/sp...rvation_networks/F_Erdbeben_Skript_HS2014.pdf

Now follow some considerations about the dependency between magnitudes and total energy.

I read this as there is a certain dependency between the length of tremor in a fault and the energy involved. The magnitudes, however, are defined via measured amplitudes, time, and the location of the instrument relative to the earthquake. This allows some conclusions about the total energy.

So maybe we could get some statements along the line Length ##\to## Energy ##\to## Amplitude ##\to## Magnitude. But the definitions of Magnitudes are independent of sizes.

Last possibility: Swiss geophysicists use different definitions than American geophysicists.
 
  • Informative
Likes Oldman too, Klystron and Bystander
  • #4,269
epenguin said:
I can only guess why your tutor laughed, maybe it sounded like impudence?
Impotence. Of the male variety.
 
  • #4,270
1647985581150.png
 
  • Haha
  • Like
  • Informative
Likes phinds, Tom.G, Hamiltonian and 7 others
Back
Top