Mathematics · Ch 5 — Two Dimensional Analytical Geometry-II
Applications of the Ellipse
5.7.2
Applications of the Ellipse
By Kepler's laws, every planet in the solar system, including Earth, orbits the Sun on an ellipse with the Sun at one focus. Some comets share this elliptical-orbit pattern (so they return periodically) — Halley's Comet, visible roughly every 75 years, has eccentricity (a very elongated ellipse). The Moon orbits Earth, and other planets' moons orbit their planets, elliptically for the same reason. …
Figure 5.51Halley's Comet's elliptical orbit
What this figure shows. The Sun at one focus with Halley's Comet's highly eccentric elliptical path sweeping out past Uranus and Neptune before returning — the classic real-world instance of Kepler's First Law. …