Stefan–Boltzmann_law | TriviaQuestions.online

⭐ Core Definition: Stefan–Boltzmann law

The Stefan–Boltzmann law, also known as Stefan's law, describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. It is named for Josef Stefan, who empirically derived the relationship, and Ludwig Boltzmann who derived the law theoretically.

For an ideal absorber/emitter or black body, the Stefan–Boltzmann law states that the total energy radiated per unit surface area per unit time (also known as the radiant exitance) is directly proportional to the fourth power of the black body's temperature, $T$ : $M^{\circ }=\sigma \,T^{4}.$

↓ Menu

👉 Stefan–Boltzmann law in the context of Runaway greenhouse effect

A runaway greenhouse effect will occur when a planet's atmosphere contains greenhouse gas in an amount sufficient to block thermal radiation from leaving the planet, preventing the planet from cooling and from having liquid water on its surface. A runaway version of the greenhouse effect can be defined by a limit on a planet's outgoing longwave radiation, which is asymptotically reached due to higher surface temperatures evaporating water into the atmosphere, increasing its optical depth. This positive feedback loop means the planet cannot cool down through longwave radiation (via the Stefan–Boltzmann law) and continues to heat up until it can radiate outside of the absorption bands of the water vapour.

The runaway greenhouse effect is often formulated with water vapour as the condensable species. The water vapour reaches the stratosphere and escapes into space via hydrodynamic escape, resulting in a desiccated planet. This likely happened in the early history of Venus.

↓ Explore More Topics

In this Dossier

⭐ Core Definition: Stefan–Boltzmann law
👉 Stefan–Boltzmann law in the context of Runaway greenhouse effect
Stefan–Boltzmann law in the context of Quark–gluon plasma
Stefan–Boltzmann law in the context of Emissivity

Stefan–Boltzmann law in the context of Quark–gluon plasma

Quark–gluon plasma (QGP or quark soup) is an interacting localized assembly of quarks and gluons at thermal (local kinetic) and (close to) chemical (abundance) equilibrium. The word plasma signals that free color charges are allowed. In a 1987 summary, Léon Van Hove pointed out the equivalence of the three terms: quark gluon plasma, quark matter and a new state of matter. Since the temperature is above the Hagedorn temperature—and thus above the scale of light u,d-quark mass—the pressure exhibits the relativistic Stefan–Boltzmann format governed by temperature to the fourth power ( $T^{4}$ ) and many practically massless quark and gluon constituents. It can be said that QGP emerges to be the new phase of strongly interacting matter which manifests its physical properties in terms of nearly free dynamics of practically massless gluons and quarks. Both quarks and gluons must be present in conditions near chemical (yield) equilibrium with their color charge open for a new state of matter to be referred to as QGP.

↑ Return to Menu

Stefan–Boltzmann law in the context of Emissivity

The emissivity of the surface of a material is its effectiveness in emitting energy as thermal radiation. Thermal radiation is electromagnetic radiation that most commonly includes both visible radiation (light) and infrared radiation, which is not visible to human eyes. A portion of the thermal radiation from very hot objects (see photograph) is easily visible to the eye.

The emissivity of a surface depends on its chemical composition and geometrical structure. Quantitatively, it is the ratio of the thermal radiation from a surface to the radiation from an ideal black surface at the same temperature as given by the Stefan–Boltzmann law. (A comparison with Planck's law is used if one is concerned with particular wavelengths of thermal radiation.) The ratio varies from 0 to 1 for ordinary surfaces.

↑ Return to Menu

Stefan–Boltzmann law in the context of "Runaway greenhouse effect"

Play Trivia Questions online!

Skip to study material about Stefan–Boltzmann law in the context of "Runaway greenhouse effect"

⭐ Core Definition: Stefan–Boltzmann law

👉 Stefan–Boltzmann law in the context of Runaway greenhouse effect

Stefan–Boltzmann law in the context of Quark–gluon plasma

Stefan–Boltzmann law in the context of Emissivity