The virial theorem is a powerful result in classical mechanics and astrophysics, particularly useful for systems of particles bound by forces, such as stars in a galaxy or gas molecules in a container. It relates the average total kinetic energy of a system to its average total potential energy.

Ternary fission is a nuclear reaction in which a heavy nucleus splits into three smaller nuclei, along with the release of energy and neutrons. This process is less common than the more widely known binary fission, where a nucleus splits into two smaller nuclei. In ternary fission, the original heavy nucleus—such as uranium-235 or plutonium-239—undergoes an instability that allows it to split into three fragments.

A Foucault pendulum is a simple device that demonstrates the rotation of the Earth. It consists of a large pendulum that swings freely in any direction, and over time, it appears to rotate relative to the surface of the Earth. This phenomenon is a result of the Earth's rotation underneath the pendulum's path. The list of Foucault pendulums typically includes notable locations around the world where such pendulums are installed.

The term "centroid" can refer to different concepts depending on the context, but generally, it denotes a point that represents the center or average of a geometric shape or a set of points. Here are a few contexts where centroids are commonly used: 1. **Geometry**: In a geometric shape (like a triangle, rectangle, or polygon), the centroid is the point where all the medians intersect.

Heliophysics is the study of the Sun and its interactions with the solar system, including the solar wind, magnetic fields, and the impact on space weather and planetary atmospheres. Numerous missions have been launched to study various aspects of heliophysics.