The Selsians utilize their own system of measurement, independent of our many, many Earth systems. If you're planning to think like a Selsian, this is a rich treasure trove of vocab you won't wanna miss!
The main unit of length in Selsimicu is derived from anthropometric (or, i guess selsiometric?) quantities! We start of with a simple base unit:
TUPFA: Length of an adult selsian's tentacle
This unit is then subdivided twice using senary magnitudes, like so:
TIKIQ: Length of an adult selsian's "noxtis", approximately
KE'U: Measuring "notch", derived from the other two
Oh, there's a unit of distance too? Yep! You don't walk with a measuring stick in hand, do you?
The basic unit of distance is:
NOKA: Distance of an adult selsian's normal, unconstrained step
This unit is then compounded heavily into the more common unit used for distance:
PWELONTU: Three unexian (3888) steps
pwelontu might look big, but the circumference of Niburu is nearly 25 thousand pwelontu long! Really, unless the distance is very short, you're more likely to see pwelontu used over noka!
Selsians have units of area and volume too, which are pretty directly just squared and cubed versions of the length units! They're named "matlescom" and "cawlescom" respectively, which translate to "slab-measurer" and "water-measurer". They are:
MATLESCOM UM TUPFA: Area of a square of side length of 1 tupfa
MATLESCOM UM TIKIQ: Area of a square of side length of 1 tikiq
matlescom um ke'u exists too, but at just 4.36 cm², around the area of a US quarter, it's not very practical to use.
Continuing on with area units, this practicality syphon only goes further, as cawlesom um ke'u is too small, at just 9ml, and cawlescom um tupfa is too big, at around 422L! In the end, only one remains:
CAWLESCOM UM TIKIQ, a.k.a. CUFĀL: Volume of a cube of side length of 1 tikiq
Mass inherits the cufāl quantity and uses it as a basis of its own unit:
CUFALUM: Mass of 1 cufāl of fresh water (at 4°C, where the density peaks)
However, from this unit is coined another, smaller unit:
KŪLTEXI: Around the mass of an apple-like fruit, hence the name
Like with noka and pwelontu (but backwards, I guess), you usually won't have to use the cufalum, since now kūltexi is the more popular unit! It's more granular, and it avoids potential confusion with the cufāl of volume. However, when that direct correlation is a benefit (i.e. for density), expect it.
Weight also inherits the cufāl quantity, but first, it'll be important to define something:
WAWFJARO: Rate of gravitational acceleration on planet Niburu
Units of weight, like the two I'm about to show, are defined under THIS gravity, and not the lighter Earth gravity of 9.8m/s². Keep this in mind. Anyways:
REÑSU: Weight of 1 "reñsu" (see below) under Niburu gravity
The "reñsu" itself is a bar of dried potato* cultivated by Selsians and Jazrajoto alike, and used as a standardized trade item. It's made so its weighs almost exactly the same as a cufalum.
As this is a physical trade item of the Jazrajoto (who use a binary~hexadecimal system), its subdivisions aren't in sixes, but rather eights! This is also so it can be physically sliced just by halving repeatedly. Thus comes:
SETOK: Weight of a slice of reñsu an eighth of the original width
These different outlooks to unit divisions means that kūltexi and setok differ by quite a bit. Something that's around 4.5 kūltexi weighs 1 setok. Not too bad of a conversion rate, frankly!
Now THAT's a whole different story. There's enough material here for it to have its very own page! ...which it does! Check out Time! for all of that.
Finally, we arrive at temperature! This unit comes from the invention of the thermometer by Selsian inventor Pitaza Micuzemta. Thus, the thermometer itself (leipitāza) and the temperature unit it utilizes are both named directly after them! This unit is:
PITAZOKA: Temperature scale used in selsian thermometers
This is all the basic units of the Selsian Measurement System, but others aren't lost! Derived units are more than possible. use terms found in the Eww Math Yucky lesson and the circumposition "sco" (where A sco B is A:B, as a ratio) and you're good to go!
TUPFA SCO PA'OKA: Speed of how many tupfa one can pass per pa'oka. Also found as 6 tupfa per pa or 216 tupfa per zupow (for easier timing)
TUPFA SCO ZTA'A PA'OKA: Rate of how tupfa sco pa'oka increases per pa'oka. pa'oka ONLY, as squaring the others leads to different units altogether
REÑSU NO'A TUPFA: Unit of energy required to push an object weighing 1 reñsu by 1 tupfa
REÑSU NO'A TUPFA SCO PA: Unit of power equaling one reñsu no'a tupfa per pa
CUFALUM SCO CUFĀL, a.k.a. MELU'OS: Density ratio between mass (in cufalum) and volume (cufāl)
OSPA: Frequency, reciprocal of pa
and so on!