Curated category
Orbits
- Orbital eccentricityIn 1953, a physicist named Walter Munk published a paper describing how the shape of an orbit determines its fate. The word eccentricity comes from Medieval…
- Orbital inclinationImagine a satellite hovering directly above the Earth's Equator. Its path traces the exact same circle as the planet's widest point.
- Semi-major and semi-minor axesThe major axis of an ellipse is its longest diameter. It runs through the center and both foci. Its ends mark the two most widely separated points on the…
- Hill sphereThe Earth's gravity well stretches into space, creating a blue line that represents its gravitational potential. A red line marks the Moon's own pull on…
- Sphere of influence (astrodynamics)Imagine a region of space shaped like an oblate spheroid where one celestial body exerts the main gravitational influence on any orbiting object.
- Kepler's laws of planetary motionIn 1609, Johannes Kepler published a book titled Astronomia nova in Prague. This work contained the first two laws of planetary motion derived from the…
- Retrograde and prograde motionA satellite marked in red circles a primary body colored blue and black, moving opposite to the central object's spin. This visual captures retrograde…