Sky science
Keplerian Orbit
Direct answer
Keplerian Orbit: A Keplerian Orbit is an ideal two-body trajectory described by a conic section under inverse-square gravity.
It is an unperturbed ellipse, parabola, or hyperbola.
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At a glance
- Found in
- Astronomy & Skywatching
- Related
- Center of Mass Orbit, Two-Body Problem, Elliptical Orbit, Parabolic Orbit
It is an unperturbed ellipse, parabola, or hyperbola.
A scientific orientation to scale, light, or motion; the article supplies the precise definition.
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The story behind Keplerian Orbit
Kepler derived planetary laws from Tycho Brahe’s observations before Newton supplied the force law.
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The Wandering Stars
How the moving planets were watched, named and found, and what a transit is.
Why Keplerian Orbit matters
Keplerian Orbit provides the reference shape for orbit elements and propagation.
Keplerian Orbit in practice: an example
An ideal planet follows a fixed ellipse with equal areas swept in equal times.
Where readings of Keplerian Orbit go wrong
Real Solar System orbits do not remain perfectly fixed Keplerian curves.
Sources and editorial method
Research references used for this entry include:
- NASA Science: Orbits and Kepler’s Laws - NASA explanation of orbital ellipses, orbital periods, and Kepler’s laws of planetary motion.
- NASA Science: Universe Glossary - NASA definitions for common stellar, galactic, orbital, and high-energy astronomy terms.
- Source
- The Great Almanac Dictionary
- Category
- Astronomy & Skywatching
- Last updated
- 2026-09-26
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Common questions
What is a Keplerian Orbit?
A Keplerian Orbit is an ideal two-body trajectory described by a conic section under inverse-square gravity.
What do people get wrong about a Keplerian Orbit?
Real Solar System orbits do not remain perfectly fixed Keplerian curves.
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