Mercury-in-glass thermometer ushered in a new era of accuracy and precision in thermometry, and is still to this day regarded as one of the most accurate thermometers available. The thermometer was used by the originators of the Fahrenheit and Celsius scales. Anders Celsius, a Swedish scientist, devised the Celsius scale, which was described in his publication "The origin of the Celsius temperature scale" in 1742. Celsius used two fixed points in his scale: the temperature of melting ice and the temperature of boiling water. This wasn't a new idea, since Isaac Newton was already working on something similar. The distinction of Celsius
Hagedorn temperature context of condensed matter physics. It was incorporated into high-energy physics in the early 1970s by Steven Frautschi and Hagedorn. In hadronic physics, the Hagedorn temperature is the deconfinement temperature. In string theory, it indicates a phase transition: the transition at which very long strings are copiously produced. It is controlled by the size of the string tension, which is smaller than the Planck scale by the some power of the coupling constant. By adjusting the tension to be small compared to the Planck scale, the Hagedorn transition can be much less than the Planck temperature. Traditional grand-unified string models