Absolute Zero is 0K

Near the heart of Scotland lies a large morass known as Dullatur
Bog. Water seeps from these moistened acres and coalesces into the
headwaters of a river which meanders through the countryside for
nearly 22 miles, until its terminus in Glasgow. In the late 19th
century this river adorned the landscape just outside of the
laboratory of Sir William Thompson, renowned scientist and
president of the Royal Society. The river must have made an
impression on Thompson--when Queen Victoria granted him the title
of Baron in 1892, he opted to adopt the river’s name as his own.
Sir William Thompson was thenceforth known as Lord Kelvin. Kelvin's
contributions to science were vast, but he is perhaps best known
today for the temperature scale that bears his name. It is so named
in honor of his discovery of the coldest possible temperature in
our universe. Thompson had played a major role in developing the
Laws of Thermodynamics, and in 1848 he used them to extrapolate
that the coldest temperature any matter can become, regardless of
the substance, is -273.15°C (-459.67°F). We now know this boundary
as zero Kelvin. Once this absolute zero temperature was decisively
identified, prominent Victorian scientists commenced multiple
independent efforts to build machines to explore this physical
frontier. Their equipment was primitive, and the trappings were
treacherous, but they pressed on nonetheless, dangers be damned.
There was science to be done.