Re: What is the absolute zero temperature?

Greetings:
The simple answer to your question is that absolute zero is -273.15 
degrees on the Celsius scale or - 459.67 degrees on the Fahrenheit scale. 
To understand how this answer comes about and what the coldest temperature 
measured to date is, I have added the following information.

Heat is a measure of the energy in matter and we measure this energy by 
measuring the matter’s temperature. The atoms that make up matter are 
constantly vibrating and as the temperature of the matter increases it’s 
energy increases and the vibration increases. Often the matter can change 
state as temperature increases as liquid water does when it boils and 
changes to steam a gas. As steam the atoms and molecules are vibrating so 
violently that they can produce great pressures to run machinery. 
Conversely as we cool matter the atoms vibrate less violently and when we 
reach cold temperatures most matter turns into a solid just as water 
freezes to ice. On the earth, near absolute zero, all elements except 
helium freeze into a solid and the atoms have a minimum of vibration, but 
not zero!

Numerical values for temperature are man made and are referenced to a 
physical state of matter, usually water, so that laboratory instruments can 
be easily calibrated . Originally the Celsius degree (C), named in honor of 
Anders Celsius (1701-44) a Swedish scientist, was formed by dividing the 
temperature range between water freezing and boiling under standard 
atmospheric pressure, into one hundred equal parts (degrees C). Thus the 
freezing point of water is zero degrees C and the boiling point of water is 
100 degrees C. The Fahrenheit scale, named in honor of Gabriel Fahrenheit 
(1686-1736), uses degrees that are 5/9 the size of the Celsius degree and 
assigns 32 degrees Fahrenheit to be the freezing point of water and 212 
degrees F to the boiling point of water.

The absolute temperature scale is measured from absolute zero in degrees 
Kelvin (K) and is named in honor of William Thomson, Lord Kelvin (1824-
1907) an English scientist that studied heat and work. A degree Kelvin was 
made the same size as the degree Celsius only the zero points are 
different. In 1954 The Tenth General Conference on Weights and Measures , 
an international standards group, defined the triple point of water to be 
273.16 degrees Kelvin. The triple point of water is a unique state of water 
at a temperature and pressure at which water exists as a solid (ice), 
liquid (water) and a gas (steam) all at the same time. This state of water 
can be duplicated in a laboratory with out much difficulty and makes it 
possible to accurately calibrate thermometers relative to absolute zero. It 
has been found experimentally that the freezing point of water under 
standard atmospheric pressure is 0.010 degrees K lower that the temperature 
of the triple point so the ice point, which is zero degrees C and 32 
degrees F is 273.15 K. Also, in answer to your question,  absolute zero is 
-273.15 degrees C or - 459.67 degrees F.

You might be interested to know what the lowest temperature measured 
to date was. In 1995 Claude Cohen-Tannoudji, who was awarded a Nobel Prize 
in Physics this year for his research, and his colleagues at the Ecole 
Normale Superieure in  Paris used a new technique called LASER COOLING to 
cool cesium atoms to the lowest temperature ever measured, 3 nanokelvins 
(0.000,000,003 degrees K above absolute zero).

Reference: B. Saubamea et al., Physical Review Letters, 27 October 97.

Best regards, your Mad Scientist
Adrian Popa