Rob Knop offers a nice discussion of the speed of light, in response to last night’s question. This post is not about that, though you should go read it.
This post is about my odd reaction to Rob’s title: “‘Speed of Light’ : a bad name for a great fundamental constant?” The notion of a “great fundamental constant” sort of suggests the possiblity of a not-great fundamental constant. Which leads to the extremely dorky poll questions:
- What is your favorite fundamental constant?
- What is your least favorite fundamental constant?
Post your answers in the comments (I’m too lazy to set up clicky-button poll software). My answers are below the fold.
This isn’t something I’ve given a great deal of thought to (honestly, if I weren’t a little punchy from lack of sleep, I probably wouldn’t’ve gotten this far on the topic in the first place), but I’d probably pick Planck’s Constant as my favorite. It’s the one I know if the most different units (2255, if you measure time in microseconds, mass in atomic mass units, and distance in hundreds of Bohr radii), and it’s connected with the wave nature of matter, which is one of the coolest things going.
The speed of light is definitely in the top five, though.
My least favorite? Probably Boltzmann’s Constant, because I can never remember the damn exponent.
Special bonus poll question: Is this the dorkiest poll ever?
e just because it keeps popping up in the strangest places.
and yes it is *S*
Last week I am starting to hang on (c^4 / G)
Avogadro’s number tends to piss me off. I can never remember where it comes from, and it seems so arbitrary. It’s not really a fundamental constant, but it still makes me cranky.
I gotta go with Planck’s for my favorite; it’s the obvious choice.
Last question: Yes.
and my least favorite: Planck Length, because it does not appears anywhere in a pure way, it always is under the roof og the square root.
I’ve always loved the Bohr Magneton. Maybe not so fundamental, though. If pressed, Boltzmann’s constant (and I always remember the exponent as being the opposite of Avogadro’s exponent…). Any constant that appears on its namesake’s tombstone is all right by me.
Least favorite: the speed of light. Mostly because it causes so much damn trouble for me when people at dinner parties find out I’m a physicist.
Favourite constant? Chaitin’s constant.
http://en.wikipedia.org/wiki/Chaitin%27s_constant
Least favourite constant?
Pi. It ruins many a beautiful calculation in a shower of irrationality.
I like G, because it is unquestionably a constant. There are many people around saying that c is not *really* a constant of nature but a mere conversion factor between space and time units, and some even say similar things about Planck constant (between energy and frequency). I’m not very sure whether those arguments are substantial or lead anywhere (though they sure fun discussions to pass an afternoon!) but just in case those people have a point I’ll stick with G.
Favorite: The fine structure constant, because of its mysterious dimensionless value and the physical significance of that value. Plank’s constant is a close runner up for the same reasons.
Least Favorite: G, for personal reasons that may change later …
This won’t be a dorky questions only if you get 50+ responses.
While we’re being dorky, aren’t they all equal to 1?
Yeah, I’m with many of you and pirates everywhere when I say “Planck’s constant!”
Least favorite? Charge of an electron probably. I mean…meh…
I’ve grown fond of the magnetic flux quantum as it generally seems to make my life easier. I can never remember its value in SI units, though, since we always use Phi_0 itself as the unit of flux.
I’ll second the speed of light as least favorite. Mainly because it arranges inconvenient resonance frequencies for conveniently sized cavities.
The universal gas constant, R, has intrigued me since junior high. I’ve always found it an interesting idea that it’s really a combination of four older ones: Boyle’s, Charles’s, Guy-Lussac’s, and Avagadro’s Gas Constants. This makes it a very interesting historical study as well as a fundamental in physical chemistry.
My favourite fundemental constant?
The IQ of IDers, 42 ain’t it
That’s Avogadro,(sp) of course.
Favorite: e, because it pops up f-ing everywhere.
Least favorite: i, because it contradicts my middle school math education. 😉
Planck’s constant. yes, the is the dorkiest poll ever 🙂
And my favorite unit of measure –
a barn mega parsec
What’s that the bartender asks?
about 2 oz
yes, physics humor is pretty bad
Hmm, that’s a hard one, because if I had to pick a favorite fundamental constant, I’d have to choose between c, hbar, and G.
I’ll pick hbar, because I’ve set c=G=1 🙂 (Which displays a bias all unto itself.)
My least favorite “fundamental” constant is Avogadro’s Number. I suppose there’s something real in there, but it’s all derivative of Boltzmann’s constant, which I consider to be more fundamental. Avogadro’s Number is all tied up into the definition of the mole, which in turn is tied up into a specific system of units (grams, as a mole is the amount of stuff where the number of grams equals the number of amu of one molecule of the stuff, if I remember correctly). I’m too much of a physicist and not enough of a chemist that I really don’t see the point of dealing with moles most of the time. I suppose it’s convenient, just like dealing with light-years is convenient if you’re talking distances or time in years, but it’s not really necessary.
You can’t get away without something like Boltzmann’s constant, though.
Whenever somebody in my class mentions Avogadro’s Number (or R, the ideal gas constant), I always scratch my head and wonder why that’s relevant. I have to remind myself that that is somebody else’s way of dealing with Boltzmann’s Constant.
The ideal gas law is REALLY
p = n k T
-Rob
I think I agree with Moshe. The constants I like most are c = k = h-bar = … = 1.
The one I like least? Hubble’s constant, just because it is not constant. But there also are all those running constants in QCD, are there not?
Favorite: e, as in e^iwt.
Least favorite: Not a fundamental constant per se, just a way of writing one: 2pihbar. I mean, why bother?
Oh, and I can offer a quick proof that your poll isn’t the dorkiest poll ever:
Who would win in an all-out smackdown?
(1) Enterprise-D
(2) An Imperial Star Destroyer
(3) Battlestar Galactica
(4) Moya
(5) A Minbari Cruiser
(6) Whatever Jack Bauer is flying
Re: charge on the electron : I became extremely confused as to what was the charge on the electron when I learned about Gaussian units in college (where you set 1/(4pi*epsilon_o)=0). Those are very elegant units, and make Maxell’s laws a whole lot nicer. But… the actual meaning of the electric charge gets confusing to me.
So I never use the charge on the electron. I always use
hbar * c * alpha
or
4pi * epsilon_0 * c * alpha
whenever I have a charge-on-the-electron. That way, I don’t have to worry about just what a “stat-coulomb” is if I happen to be in Gaussian units.
-Rob
Definitely alpha_s.
Avogadro’s number rocks! I don’t have a least favorite fundamental constant, really, although converting certain constants to certain units can make me cranky.
And, I’ll bet you could come up with a dorkier poll if you put your mind to it!
Kary Mullis, inventor of the polymerase chain reaction, was no fan of Avogadro’s number either: “[It] is not an intrinsic chemical constant… It is derived from a measurement of the size of the Earth heroically made by the French in the eighteenth century. The number depends on the Gram which came from the Cubic Centimeter full of water at 4 ËC, which derived from the Meter, which had been defined as one ten-millionth of the distance from the North Pole to the Equator along a line passing between the Nôtre-Dame and the guy selling chestnuts there in the winter of 1799.” [Mullis, K. B., (1991) in “PCR Methods and Applications,” Cold Spring Harbor Laboratory Press, NY, p. 1.]
me too for Planck as fave.
Avogadro’s number is just a conversion factor between daltons and grams, boo. On the other hand, guacamole with that Mexican chocolate sauce might be interesting…. 🙂
I’ve heard odd rumors that G isn’t all that constant, or at least that the measurements of it never seem to agree to more than four decimal places or so. Talk about your uncertain principles….
My favorite constant is e, naturally.
my least favorite is epsilon_0, for totally arbitrary reasons of course
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h-bar for me, simply because I use it alot more than h, plus it looks cool
As for my least favorite constant, probably the parsec, a parallex of one arcsecond? how arbitrary can you get!
I am not sure it really counts, but I hate when spectroscopists measure energy in units of 1/cm. I imagine it is quite convenient if you are dealing with transitions all the time, but it sure is confusing.
I’ve heard odd rumors that G isn’t all that constant, or at least that the measurements of it never seem to agree to more than four decimal places or so. Talk about your uncertain principles….
G is just hard to measure. That’s another kind of uncertainty from principled uncertainty….
my favorite is any constant that does not change over time
my anti-favorite is any constant invented as a fudge factor
Haven’t you heard? The only canstant is change. So empty your pockets.
My least favorite is stupidity. It permeates EVERYTHING.
1. The fine structure constant. Unless you’d alow Ï?
2. ε & μ, the permittivty and permeability of free space, a stupid redunancy of SI …
My favorite is probably c. It’s certainly the one that shows up most commonly in my calculations, anyway.
My least favorite is the Bohr magneton, because magnetism is a strange and annoying force.
My favorite … 42!
Well, my real fav is h-bar. I love showing my students the shorthand for h/2pi.
Least favorite is the Boltzmann Constant, because (1) I rarely never use in class and (2) the students confuse it with the electrostatic constant k, since our text (C&J) has Boltzmann’s on the inside front cover. They never seem to check the name of the damn thing in the table.
Yes, this poll is dorky, and would lead visitors to believe we’re all, well, dorks. As for starships kicking butt, the White Star would win hands down.
Most definitely the fine structure constant. Especially in light of a lovely little formula for the speed of a 1s electron, v=Z*a*c. If a is ~1/137, solve for v when Z (the atomic number) = 138… 😀
Favorite: Planck’s Constant
Least: Permebility of Free Space
Favorite — I’ll go with h-bar (’cause it gets pi in there too.) But I think you should count votes for h and ħ together.
Least favorite — epsilon nought, permittivity of free space. Well, either that or the so called “impedence of free space,” η. Because I recently had to TA an E&M class in our electrical engineering department, and trying to do problems where the “real” electric field E is never mentioned (they use D from the beginning, in every problem, even though to me it seems like a much more abstract quantity. E & P I have a physical intuition for, but D seems artificial) and where the behavior of light is explained in terms of signals on transmission lines… hurts my head.
Favorite constant – Plank’s constant, I guess. I’m not an engineer anymore, so I’ve forgotten some of my favorites.
Least favorite – permittivity of free space. I don’t know why. Maybe I just didn’t like E&M.
As for the dorkier poll… I was in the EE Honors program at my undergrad. During one of our classes, someone started circulating a note to the students. It was like in high school, when someone would pass around a poll where everyone could vote on who was the cutest boy/girl/whatever. For this one, the question was “What is your favorite number?” The choices were 0, pi and e. At the end of class, the girl who started the poll berated us for voting for pi, when clearly e is a much better number. (I actually voted for 0.)
Favorite: mu_0, as in the e-mail address :P. Why? Because magnetism remains intriguing, even after an M.Sc. in physics.
Least favorite: I’ll have to go with an earlier commenter and vote for c, because it makes being a phycisist annoying at parties.
Actually, something very close to this poll has been done before, sort of. And of the actual constants in that list, it looks like Pi was the winner.
Favorite: G
Least favorite: permittivity and permeability, as Cygnus said.
My officemate’s votes are charge on the electron as favorite, h-bar as least favorite (though oddly he’s fine with just h).
Regarding the dorkier poll, the key question is whether the fighters are included. If so, it’s either the Star Destroyer or Battlestar, nothing else comes close. I’d expect the outcome of that particular duel to be either a bunch of Vipers or TIEs milling around with no place to land once everything else on the map gets blown up. Without fighters, it’s more interesting. Probably the Star Destroyer just from sheer size, though the Minbari Sharlin could be a contender, especially if it can start at long range and start retrograding. Star Trek would be better represented by the Sovereign (Enterprise-E) rather than the Galaxy (Enterprise-D). Interestingly, the first five choices are all playable in the Babylon 5 Wars game system (four of them as unofficial crossovers, of course)…
When I got here today, it was just delightful that the poll question was:
“What’s your favorite constant?”
and the page said
“Comments: 42”
Well, of course.
Put me down as another vote for e.
c.
useful,and also *almost* a nice round number.
the only DIMENSIONLESS fundamental physical constant mentioned so far, that I could see, is the fine structure constant (for sake of dorkiness let us say alpha around 1/137)
if you are talking about having a dorky poll, you are not even trying unless you have one about favorite DIMENSIONLESS physical constants
it is just a pathetic half-hearted effort if you allow people to say things like Planck h-bar and G and c and elementary charge, which as Moshe titteringly indicated are units—and can be adjusted to be one.
while I am being grouchy, let me say that pi is not a phyiscal constant. It is a mathematical constant that would be the same in any universe. And also i the square root of -1 and e the base of natural logarithms. that is just pure numbers, like summing a series.
the reason I am feeling grouchy is that I would be really interested to hear what your readers come up with if the popularity constest was about DIMENSIONLESS physical constants—-which are significant RATIOS built into the universe. Like the ratio of mass of proton to mass of electron, or the ratio of Planck mass to proton mass.
these are things you can’t simply make become = 1 and in effect “go away” merely by adjusting the system of units. and so they are enduring mysteries.
==========
that said, thank you for having this very nice dorky poll!
my favorite dimensionful constant is not even fundamental—the chandrasekhar limit of around 1.3 solar masses—I like it because it helps make supernovas.
sorry about being in a foul temper earlier today. it was about something else.
the poll is not dorky. it makes good sense, as does Moshe’s comment that
some of these things can be set to one.
favorite: 0, otherwise math would be nothing.
least fav: 1/2 of a bit of information, since I cannot yet prove it exists.
Least favourite: Hubble’s Constant – because it is not
Favourite: 4π
Favorite: CP-violation phase
Least Favorite: Epsilon_nought
We can get one more comment on this, right?
favorite: I’ll join the fine structure constant party. But you all know alpha=1/136, don’t you?
least favorite: I’ll pick the top quark to up quark mass ratio as my least favorite. Why’s the top quark so darn heavy compared to the stable particles? If I wanted the mass of a heavy metal, I’d get something nice and stable like gold. Who wants a single quark that might not even have time to get dressed before it dies?
OK Mr. Post, how does it feel to no longer be “extremely dorky”?
Boltzmann’s constant.
Ranting about dimensionless constants should be an honorary Godwin’s law violation.
Definitely pi. It was the first constant and first irrational number I was introduced to and I found the idea that it never ends extremely cool.
The next runner up is h-bar. Why? Because of a conversation I had with my Intro Physics prof about h when I went and asked exactly what it was because everything else in whatever formula I was wondering about actually came from somewhere – and h-bar is more fun that plain h.