  Many quantities are attributed a range of values that can apparently extend
to infinity (on one side or both sides). In this respect, the definitions of
their measurement units do not place any constraint to the maximum (or minimum)
value for their validity. In general, that happens because those extreme values
are far from being reached on the earth, or presently in experiments. However,
since the same units are used also in fields of physics, chemistry or
technology where they could occur, namely in the description of the universe in
one sense, and in nano-scale or particle physics in another sense, the issue of
extreme values (not in statistical meaning here) is not irrelevant. The
question placed and discussed in this paper is whether the present kelvin
scale, based on Lord Kelvin second definition (our currently accepted concept
of temperature), applies over a full range between bounds (zero, infinite) or
not, and about the concept of temperature in itself in the extremes regions.
The aim, however, is not to provide an answer, but to suggest there are
difficulties with the application of current concepts at extremes of
temperature.
