Planck temperature, denoted by T_P, is the unit of temperature in the system of natural units known as Planck units.

It serves as the defining unit of the Planck temperature scale. In this scale the magnitude of the Planck temperature is equal to 1, while that of absolute zero is 0. Other temperatures can be converted to Planck temperature units. For example, 0°C = 273.15K = 1.9279 × 10^-30T_P.

The Planck temperature is defined as:

Failed to parse (Missing texvc executable; please see math/README to configure.): T_\text{P} = \frac{m_\text{P} c^2}{k} = \sqrt{\frac{\hbar c^5}{G k^2}}

1.416833(85) × 10³² K / - where:

The two digits between the parentheses denote the standard error of the last two digits of the estimated value.

As for most of Planck units, a Planck temperature of 1 (unity) is a fundamental limit of quantum theory, in combination with gravitation, as presently understood. At temperatures greater than or equal to T_P, current physical theory breaks down because we lack a theory of quantum gravity.

David Nathaniel Spergel (born March 25, 1961), is an American theoretical astrophysicist and Princeton University professor (currently chair of the Department of Astrophysical Sciences) known for his work on the WMAP mission. Professor Spergel is a MacArthur Fellow. He has served as the chair of the Astrophysics Subcommittee of the NASA Advisory Council and was once the W.M. Keck distinguished visiting professor at the Institute for Advanced Study in Princeton, New Jersey. Not only has he focused on deciphering the data that the Microwave Anisotropy Probe (MAP) beams back from space, he was part of the team that dreamed up the mission and designed the satellite that would carry it out. Spergel is the Charles A Young Professor of Astronomy and a member of the National Academy of Sciences. He shared the 2010 Shaw Prize in astronomy with Charles L. Bennett and Lyman A. Page,Jr. for their work on WMAP (Wilkinson Microwave Anisotropy Probe).

Spergel was born in Rochester, New York, and attended John Glenn High School, Huntington, NY. He obtained a Bachelor's degree in Astronomy (summa cum laude) from Princeton University in 1982, and was a visiting scholar at Oxford University in 1983. He obtained his master's degree (Astronomy) at Harvard University, 1984, and his doctorate (Astronomy), Harvard University, 1985, with a thesis entitled Astrophysical Implications of Weakly-Interacting Massive Particles.

Max Karl Ernst Ludwig Planck, ForMemRS, (April 23, 1858 – October 4, 1947) was a German physicist who discovered quantum physics, initiating a revolution in natural science and philosophy. He is regarded as the founder of quantum theory, for which he received the Nobel Prize in Physics in 1918.

Planck came from a traditional, intellectual family. His paternal great-grandfather and grandfather were both theology professors in Göttingen; his father was a law professor in Kiel and Munich; and his paternal uncle was a judge.

Planck was born in Kiel, Holstein, to Johann Julius Wilhelm Planck and his second wife, Emma Patzig. He was baptised with the name of Karl Ernst Ludwig Marx Planck; of his given names, Marx (a now obsolete variant of Markus or maybe simply an error for Max, which is actually short for Maximilian) was indicated as the primary name. However, by the age of ten he signed with the name Max and used this for the rest of his life.

He was the sixth child in the family, though two of his siblings were from his father's first marriage. Among his earliest memories was the marching of Prussian and Austrian troops into Kiel during the Danish-Prussian war of 1864. In 1867 the family moved to Munich, and Planck enrolled in the Maximilians gymnasium school, where he came under the tutelage of Hermann Müller, a mathematician who took an interest in the youth, and taught him astronomy and mechanics as well as mathematics. It was from Müller that Planck first learned the principle of conservation of energy. Planck graduated early, at age 17. This is how Planck first came in contact with the field of physics.