Kramers' law, named after physicist Hendrik Anthony Kramers, primarily refers to a concept in the theory of reaction rates and transition state theory in chemical kinetics. This law provides a framework for understanding how a system transitions from a metastable state to a stable state, particularly in the context of chemical reactions where a reactant must overcome an energy barrier to transform into products.

Dredge-up is a process occurring in stellar astrophysics, particularly in the context of red giant stars. It involves the mixing of materials from the interior of a star to its outer layers, specifically bringing nuclear fusion products from deeper layers, such as helium and heavier elements, to the surface. This process typically happens during specific phases of a star's evolution, notably during the red giant phase when a star expands and cools.

A helium flash is a crucial astrophysical event that occurs in the later stages of a star's life, particularly in low- to intermediate-mass stars (like those in the range of about 0.8 to 8 solar masses). This phenomenon happens when the core of a red giant, primarily composed of helium, becomes sufficiently hot and dense to ignite helium fusion after a period of hydrogen burning in the star's earlier life stages.

The term "instability strip" can refer to several different concepts depending on the context, but it is most commonly used in meteorology and atmospheric science. In this context, an instability strip is a region in a diagram that represents the stability properties of the atmosphere, particularly with regard to convection. In meteorology, the instability strip typically refers to a band on a thermodynamic diagram, such as a skew-T log-P diagram, where certain conditions indicate that the air is unstable.

The mass-luminosity relation is an important empirical relationship in astrophysics that describes how the luminosity (the amount of light energy radiated per unit time) of a star is related to its mass. This relationship is particularly applicable to main sequence stars, which are stars that are in the stable phase of hydrogen burning in their cores.

Photo-erosion refers to the process by which materials, such as soil, rock, or other surfaces, are gradually worn away or eroded due to exposure to light, particularly ultraviolet (UV) radiation from the sun. This phenomenon can occur in various geological and environmental contexts, often influencing the stability and structure of landscapes.

The Cahn–Hilliard equation is a partial differential equation that describes the phase separation and motion of interfaces in a binary mixture or alloy. It is particularly important in materials science, as it models the process by which two phases of a material (such as solid and liquid) separate from each other, leading to the formation of distinct microstructures over time. The equation was introduced by John W. Cahn and John E.