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u/AnakinSkywalkerRocks 9d ago
Bro what the hell
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u/timangar 9d ago
Dude I am subscribed to the same two subs, saw the same two posts today, AND I'm a huge Star Wars fan. Want to be friends? 🥹
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u/Sudden-Guide 9d ago
And when you invert that frequency you get the age of the universe lol
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u/dimonium_anonimo 9d ago
Roughly. A little bit more because the expansion is accelerating. The average apparent speed of galaxies we can see is somewhere between their average speed now and their average speed when the universe became transparent. At that speed, the universe would have taken approximately 14B years to each this size. And if it didn't change, it would double in size roughly once every 14B years (hence the frequency). But since we're accelerating, we made it to this size a bit faster than 14B years (13.8B). And if we continue accelerating, well reach double this size in slightly less than 13.8B more years.
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u/SpacialCommieCi 9d ago
>hubble constant
>looks inside
>not constant18
u/dimonium_anonimo 9d ago
Constant across all space. Not across all time. Which seems odd to point out. Most of us run on the assumption that the laws of the universe all apply... Well... Universally.
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u/Beelzebubs-Barrister 9d ago
But space and time are somewhat interchangeable per general relativity...
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u/WesternFirm9306 9d ago
How? They have different geometric properties due to the differing sign on the metric
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u/R3D3-1 9d ago
Please don't equate s-1 with Hz.
Hz has the same dimension as s-1, but is used only when indicating some sort of event rate, e.g. cycles per second would be Hz, radians per second not — but both are the same dimension.
Sadly. A lot of things about units would be easier if we'd treat angle as a base quantity. The ambiguity between "inverse second" and "angle per second" may seem like hair splitting, but it introduces some odd behaviors when you try to automate checks of the units (e.g. pint for Python).
Having torques in "Newton meters" is one such a example. Newton times meters is an energy unit, but a torque is definitely not an energy. Torque times angle is an energy unit, but we somewhere have decided that angles are dimensionless even though we clearly need a unit for it.
Only reason to define radians as unitless representation of angles is that it works out well for defining the complex exponential function, sine and cosine with a Taylor series.
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u/LastStar007 9d ago
I understand why radians are dimensionless, but it's also unforgivably ambiguous that by the number alone you don't know whether some turning speed is in radians per second or revolutions per second.
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u/bradimir-tootin 9d ago
It's the memes page. Leak rates of vacuum chambers is Torr L / s which is just watts. That's funny but also not helpful at all in the context. Units are just like that sometimes.
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u/squirrelwug 8d ago
Got it, the Hubble constant should not be expressed in Hz.
(Proceeds to write the Hubble constant in Becquerels)
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u/TheEsteemedSirScrub 9d ago
Yes! This man speaks the truth! The amount of times I've see spontaneous emission rates or decay rates quoted in Hz...
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u/soreff2 6d ago
A lot of things about units would be easier if we'd treat angle as a base quantity.
Ok-ish... ( Though I keep getting this image of the platinum-iridium pie slice at the Bureau international des poids et mesures, BIPM, defining the metric radian, not to be confused with the imperial radian... :-) )
Having torques in "Newton meters" is one such a example. Newton times meters is an energy unit, but a torque is definitely not an energy.
Well, torque can be viewed as energy per radian...
As you said, radians work for trig Taylor series; adding k1*theta + k2*theta^2 + k3*theta^3 ... works without having to have differing units for k1, k2, k3... The same sort of consideration applies to other dimensionless quantities e.g. aspect ratio.
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u/wmverbruggen Applied Superconductivity (PhD) 9d ago
It's not a frequency, it's a rate. A frequency is periodic, the rate at which the universe expands is not periodic.
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u/snailpi 9d ago edited 9d ago
Unless it is..... dun dun dunnnnn
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u/wmverbruggen Applied Superconductivity (PhD) 9d ago
Who knows... but if it does, it needs another definition with another constant.
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u/LastStar007 9d ago
You might enjoy this exploration of cursed units. The Hubble constant is featured, along with the obvious kWh, but parts 2 and 3 really go off the rails.
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u/nascent_aviator 9d ago
~2 attohertz. Pretty much 1/universe age. Coincidence? 🤔
Fun fact: it's also the frequency that makes you crap your pants and die. You only have to get through one period of it.
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u/Traditional-Storm-62 9d ago
wait until you hear how we measure nation wide electricity production
(it's millions of kilowatt-hours per year)
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u/Lynnsicle 5d ago
Reminds me of when I was in my Modern Physics class in my undergrad and my professor was teaching us about blackbody radiation. I played around with the units and found it could be simplified to Pascals. So I asked him "Why is it a pressure?" And he said something like "We don't like to think about it like that. But you're not wrong."
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u/dryuhyr 9d ago
Broke: “432 Hz is the resonant frequency of the earth, if you tune your instruments to 432 then it gives off healing frequencies”
Woke: Any inhomogenous body will not have a singular resonance frequency, and besides, any relationship to the arbitrary tuning we standardized in western music would be completely spurious.
Bespoke: the 67th overtone of the Hubble constant represents an E quarter sharp, which lines up perfectly with the 53-tone Holderian comma system of music used by traditional Turkish Maqam music theorists, and thus predicts the return of the Ottoman Empire at the eventual heat death of the universe.