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Science Memes @mander.xyz

fossilesque @mander.xyz

8mo ago

Seconds

78 comments

Also angles
Would love to hear how mass is measured in seconds though
- Set G = 1 and c =1. Then equations like r = 2m make dimensional sense.
  https://en.m.wikipedia.org/wiki/Geometrized_unit_system
  
  My brother, that explanation is not nearly dumbed down enough and as with most math wiki is useless for eli5 stuff.

Angle: seconds
- Dessert: seconds
  
  Motion: seconded

Rocket scientists be like:
Fuel efficiency: seconds.

Wait, how do you measure mass in seconds?
- Time taken for me to eat that mass of hotdogs
  
  Choking_Hazard.txt
- Just as particle physicists measure everything in energy (eV to be precise...)
  Mass? eV Energy? eV Distance? 1/eV Time? Guess what: 1/eV as well! This also means velocity has unit 1...
  And the worst part: it turns out to be extremely useful!

Why is the astrophysicist wearing gloves? Is he trying to dispose of a body?
- You don't want to know what an astrophysicist does in their free time.
  
  Well the one I knew spent his free time doing community theater, having many of the women there go crazy over him (he was good-looking and charming), and then not sleeping with any of them because he was a wait-until-marriage religious guy. I don't think he was typical.

Fun fact: Seconds are called seconds because the first breakdown of an hour is the minute, and the second breakdown is the second. Don't ask me the obvious question(s) because I don't know.
- If by obvious question you mean “why is it called a minute,” that is because “minute” means “small.” So you have the first minute (small) part and the second minute part of the hour.

Mass in seconds? How? I get mass in Joules, but seconds?
- There are two possibilities I can think of:
  Orbit duration can be used to calculate mass
  The diameter of a star or the parallax distance on the sky (in arcseconds) can also be used to evaluate mass
  
  Size doesn't say much about mass though.
- I measure the mass of my stool by seconds it takes to discharge
- Well the modern definition of a kg is based off of the second and the metre https://en.m.wikipedia.org/wiki/Kilogram :P
- The amount of time a mass M attracts a unitary sphere up into CoM.

Me: not smart enough to understand
Brain: Quick! Say something to sound like you fit in!
Me: uh ... I just did the Kessel Run in under 12 parsecs!
- But do you remember the Krebs Cycle?
  
  !https://i.ytimg.com/vi/27x0wiuTYoE/maxresdefault.jpg

I'm hungry for more; may I have seconds?

That may be relativists (they would actually measure anything in units of mass, with everything else defined through G = c = 1). Astrophysicists commonly measure mass in solar masses, long distances in parsec (or kiloparsec, megaparsec), short distances in solar radii or AU, and time in whatever is relevant to their problem (could be seconds or gigayears)
- short distances in solar radii
  I think astrophycisists and I may have a difference of opinion on the meaning of the adjective short

As a theoretical physicist, units are for chumps
- It's easy to remember c and ℏ if they're both 1...
  
  Constance? Never heard of her
- You must love Reynold’s Number:
  https://en.m.wikipedia.org/wiki/Reynolds_number
  
  Oh god, no fluid mechanics is way too difficult. I stuck to studying quantum effects of black holes, which is much easier.
  (This isn't a joke, it's literally true)

Everything should just be in eV. Particle physics natural units are the best.
- Yes. We need to move from metric to intergalactic units.

angle: seconds
- Rads. But radians are fine too.
  
  Tau (τ). A full circle is just 1τ instead of 2π.

all the same thing anyway

If you ever find yourself among theoretical physicists and/or astrophysicists and need a conversation starter, just ask about unit systems or unitless/natural measurement systems. There is no other profession that is more obsessed about that topic.
Just to put this here:
ħ=1

Don't they measure distance and time by redshift (ie colour)
- What even is color if not seconds^-1?
  
  Yeah true, but I think they actually use wavelength of red shift, which is distance.... traveled by light in the time it takes to make a full cycle. So I guess we're back to seconds again.
  I think they use this for distance and time because at scales being dealt with they have the same implications.
- They normally use parallax-seconds, i.e. parsecs, for long distance objects.
  
  I think you need to be more specific than 'long distance', yes they use parsecs for 'long distances' but I believe only for intra-galactic objects. I think other galaxies are too distant for parallax seconds to be useful.

Please Sir, can I have some more?
Lash him! Ridicule him! This boy wants seconds!

Acceleration….
- Sounds like that reduces to hertz, which I'm sure they'll just express in seconds.
  
  They like to set the speed of light to be 1. That is dimensionless 1. It makes their calculations simpler this way instead of dragging some power of c everywhere like a loosely connected trailer on a dirt road.
  When i took a particle physics class we measured everything in energy (eV). In this case of measuring everything in seconds, acceration would be measured in units of 1/s

Shouldn't m = F/a so n/s^2?
- E=mc^{2 so m is joule seconds}2 / meter ^ 2
  F=ma so m is Newton seconds^2 / meter
  A joule is 1 Newton / meter so they agree
  
  A joule is 1 Newton / second, but those units do still agree

I know some people that should measure their weight in mass per second.

Can I get a conversation table?

I don't know anybody using just seconds. I use natural units and my simulation buddies use their funny cgs units.

78 comments