circularize

Circularize means to convert something into a circle or circular form. The term is used across fields such as aerospace, astronomy, biology, and linguistics to describe processes that produce a circular shape, loop, or closed structure.

In orbital mechanics and spaceflight, circularization refers to turning an elliptical orbit into a circular one by adjusting velocity at a specific point, usually at perigee or apogee. The maneuver sets the orbital eccentricity to zero, yielding a constant altitude at that radius. Operators use circularization to maintain stable, predictable orbits or to prepare for subsequent phases of a mission.

In astrophysics, tidal circularization describes the gradual dampening of orbital eccentricity due to tidal forces between closely interacting bodies, such as a planet and its star or the components of a binary star. Over long timescales, tides tend to make the orbit more circular unless external perturbations continually disturb it. The effectiveness depends on factors such as distance, mass, and the internal dissipation properties of the bodies involved.

In molecular biology, circularization can refer to ligating the ends of a linear DNA fragment to form a circular plasmid, or to the existence of circular RNAs formed by back-splicing. Circularization can enhance stability, influence replication or transcription, and affect gene regulation in various cellular contexts.