2312: mbmbam

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Hello and welcome to Millibar Millibarn Attometer, an advice show for the Planck era.
Title text: Hello and welcome to Millibar Millibarn Attometer, an advice show for the Planck era.


Ambox notice.png This explanation may be incomplete or incorrect: Created by 10^-47 BROTHERS. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.
If you can address this issue, please edit the page! Thanks.

In part, this comic is an homage to the referenced podcast, My Brother, My Brother, and Me, which often features rapid garden-path conversations and puns and double entendres that are at once groan-worthy and delightfully witty.

The millibar is a metric unit of pressure, equal to a thousandth of a bar, or 100 Pa. The millibarn is a metric unit of area, equal to a thousandth of a barn, or 10^-31 m^2. Both units would theoretically have the symbol mb (though mbar for the pressure unit is more common).

Hence, mbmb (the pressure unit multiplied by the area unit) would be a unit of force. Applying a bit of dimensional analysis, pressure x area = (force/area) x area = force.

am would be the symbol of an attometer, or 10^-18 metres. Multiply that to create the unit mbmbam, which would be a unit of energy. Specifically, it would be a unit of work: the energy expended to move an object. More dimensional analysis: force x distance = (work/distance) x distance = work. The actual value of 1 mbmbam is correctly calculated in the comic: 100 Pa x 10^-31 m^2 x 10^-18 m = 10^-47 J.

The final panel is an extended series of puns--that yeast rises, for one (implicitly of a spontaneously generated energy, a reference to black body radiation); a second soon follows about spacetime having unleavened dimensions in string theory. This seems to be a punning reference to spacetime having eleven (actually, ten--M theory says eleven) dimensions in string theory, while continuing to play on the theme of yeast--in this case, the universe is presumably flat because some of its dimensions lack the Planck yeast that would make them rise.

The example of lifting a yeast cell used in comic is one of many interpretations of the work. Another interpretation of 1 mbmbam would be the work necessary to pull two socially distancing (6 ft) COVID-19 virons apart by the thickness of one strand of hair, against the gravity they exert on each other.


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[Cueball, Megan, and White Hat are standing next to each other, talking. Megan has her hands raised to the side, in a shrugging gesture.]
Megan: Odd how in physics "mb" is both millibars (pressure) and millibarns (area).
Megan: mbmb could mean millibar-millibarn, which is a unit of force, strangely.
White Hat: Units are weird.
[Same scene - Megan is now checking her phone. White Hat is raising his right index finger.]
Cueball: So what's mbmbam, the My-Brother-My-Brother-And-Me unit?
Megan: Millibar-millibarn-attometer, I guess? That'd be a unit of energy. 10-47 Joules.
White Hat: "One podcast"
[Same scene in a frameless panel. Megan holds her phone to her side. White Hat has his arms raised to the side, excited.]
Cueball: 10-47 sounds small.
Megan: Yeah, it's roughly the energy you'd need to lift one yeast cell by one Planck length in Earth's gravity.
White Hat: Planck yeast!
[Same scene in a regular panel. Megan has put away her phone, and has her right index finger raised. White Hat has his hands balled into fists, frustrated.]
Cueball: Doesn't Planck yeast rise on its own?
Megan: Yeah, that's what makes quantum foam. But data suggests our universe is flat.
Megan: String theory says it's because spacetime has unleavened dimensions.
White Hat: ... I hate you.

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So ... what would the MMMbop unit be?

the power of love

This has gotta be at least the third or fourth time he's referenced MBMBaM. https://what-if.xkcd.com/155/ and https://xkcd.com/1836/ I know are two more examples, but there might be more. 00:54, 28 May 2020 (UTC)

Am I the only one thinking that mbmbam should be a unit of work, not energy? Force x distance... High school physics was a long time ago though. Philosophicles (talk) 03:15, 28 May 2020 (UTC)

Work is energy 05:28, 28 May 2020 (UTC)
The only difference could be absolute or relative energy, comparable to height above sea level vs. distance. Sebastian -- 06:36, 28 May 2020 (UTC)
My first instinct was "that´s a torque". But of course angles have no unit, and so torque and energy must have the same. -- 07:15, 28 May 2020 (UTC)
Please forgive my ignorance here: Is not a "degree" an angular unit?
ProphetZarquon (talk) 17:20, 29 May 2020 (UTC)
The concept that a plane angle is a dimensionless unit is a tenet of the International System of Units (SI). It works something like this. "Degrees" and "Radians" are two ways of expressing the same thing, the size of an angle. If you have an angle and you draw an arbitrary circle with the angle's vertex as the circle's center, so that your angle now "subtends" an arc of the circle, then the size of your angle in radians is defined to be the length of that arc divided by the length of the radius of the circle. The circumference of the whole circle has length 2π·r, so an angle of 360 degrees is also an angle of 2π·r/r radians. The numerator and the denominator are dimensionally both lengths. Dividing a length by a length yields a dimensionless quantity, i.e. one with no "unit". Consequently radians are dimensionless, and so are degrees. JohnB (talk) 19:52, 29 May 2020 (UTC)

Is my vision going blurry, or does that second panel say "milliibarn"? -- Peregrine (talk) 09:09, 28 May 2020 (UTC)

Yes, two 'i' before the barn. That must be a mistake. -- 10:28, 28 May 2020 (UTC) <-- Either that or it's milli - i*barn, going into imaginary dimensions. Cellocgw (talk) 11:58, 28 May 2020 (UTC)
MBMBaM's tagline is "an advice show* for the modern era", not an advice podcast.
Reminds me of how this symbol: "μ" means both "micro" (micrometer is μm.), and "friction" (frictional constant of X would be μ = X), and the population statistical average (the average acceleration due to gravity on the surface of earth is μ_gravity), and something like 20 other things according to this wikipedia article: https://en.wikipedia.org/wiki/Mu_(letter)#Use_as_symbol Tsumikiminiwa (talk) 15:53, 28 May 2020 (UTC)
Reminds me of the old joke: Several kittens have found their way up onto a sloping roof, which one falls off first? The one with the lowest μ... 21:52, 29 May 2020 (UTC)
"It's an advice show for the modren era", not modern. 19:35, 28 May 2020 (UTC)

I went ahead and removed the statement that "mbar" is more common than "mb," since the preferred abbreviation depends on the field. In atmospheric science, "mb" is nearly universal. 17:19, 28 May 2020 (UTC)

anyone following that podcast who can shed light on the arrangement of the dashes? why is there non between "and" and "me" but between all the other words? (my-brother-my-brother-and (how do I emphasize a space?) me) --Lupo (talk) 06:40, 29 May 2020 (UTC)

Can anyone please explain (to me) the role of white hat in this comic? He is not part of the conversation and just makes more or less random statements, concluding in "I hate you". What am I missing here? Bischoff (talk) 19:54, 2 June 2020 (UTC)

For most of the dialogue, Megan and Cueball are discussing some oddities of dimensional units and making puns, while White Hat struggles to keep up. His utterances can be seen as 1) True but lacking insight ("UNITS ARE WEIRD") 2) A valid pun but out by about 10^50 ("ONE PODCAST") 3) Freaking out because it is all too weird for him ("PLANCK YEAST!") 4) Final breakdown due to some very high level punning by Cueball and Megan ("...I HATE YOU")

In the last panel, Cueball and Megan link Planck yeast (not a thing) and unleavened (yeast-free) bread to several concepts in theoretical physics: Quantum foam, the curvature of space time, and M-theory. M-theory suggests that space-time has eleven ("unleavened") dimensions, and is described by Wikipedia (https://en.wikipedia.org/wiki/String_theory) as a unification of superstring theories. The five consistent versions of superstring theory apparently suggests that space-time has only ten dimensions, so this may be a rare error by Randall. Or I may just have misunderstood. --Paul Seed 21:34, 28 June 2020 (UTC)


I cite wikipedia:

The unit's official symbol is bar; the earlier symbol b is now deprecated and conflicts with the use of b denoting the unit barn, but it is still encountered ...

I wonder since when, und who still uses *mb*, since I have never encountered that in my life. -- 04:05, 29 May 2020 (UTC)

never seen it either. But the comic doesn't state that it is common, just that it is possible. See also comment above on atmospheric science. --Lupo (talk) 06:40, 29 May 2020 (UTC)
Here's a link to a page with multiple uses of mb with the meaning millibarn. It's in the CRC Handbook of Chemistry and Physics (97th ed., 2016), a "comprehensive one-volume reference reasource for scientific research". JohnB (talk) 13:28, 29 May 2020 (UTC)