The Sun is also a star.

SI Units: Time, Length, Mass, Current, Amount of Substance, Temperature, Luminous Intensity


The International System of Units (SI, Système international (d’unités)) consists of 7 base units

Sl. NoQuantityDefinitionUnit
1.TimeThe duration of 9192631770 periods of radiation, corresponds to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.second
2.LengthThe distance traveled by light in a vacuum in 1/299792458 seconds.meter
3.MassThe kilogram is defined by setting the Planck constant h exactly to 6.62607015×10−34 J⋅s (J = kg⋅m2⋅s−2), given the definitions of the meter and the second.kilogram
4.Electric CurrentThe flow of exactly 1/1.602176634 x 10-19 times the elementary charge e per second. Equalling approximately 6.2415090744×1018 elementary charges per second.ampere
5.Thermodynamic temperatureThe kelvin is defined by setting the fixed numerical value of the Boltzmann constant k to 1.380649×10−23 J⋅K−1, (J = kg⋅m2⋅s−2), given the definition of the kilogram, the meter, and the second.kelvin
6.Amount of substanceThe amount of substance of exactly 6.02214076×1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol−1mole
7.Luminous IntensityThe luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 5.4×1014 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.candela

Also see Betelgeuse is Surprisingly Smaller, Closer to Us.

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