# Caveats

## Temperatures are relative

Alicorn treats temperatures (as well as all other quantities) as relative rather than absolute. In consequence, when converting from kelvin to degrees celsius, no offset is added:

julia> ucat = UnitCatalogue() ;

julia> T = 20 * ucat.degreeCelsius
20 °C

julia> inUnitsOf(T, ucat.kelvin)
20.0 K

## Only dimensions are compared

Alicorn is only aware of physical dimensions, not of the physical quantities as such. The responsibility to choose units suitable for a given physical quantity rests with the user. For example, it is possible to add two quantities that have the same dimension but represent different physical concepts, such as angles and solid angles:

julia> ucat = UnitCatalogue() ;

julia> solidAngle = 1 * ucat.steradian
1 sr

julia> angle = 1 * ucat.degree
1 °

julia> nonsense = angle + solidAngle
58.29577951308232 °