Focus is a point where rays of light or other radiation converge or from which they appear to diverge. In astronomy, it often refers to the points in an elliptical orbit around which celestial bodies revolve.
5 Must Know Facts For Your Next Test
In Kepler's First Law of Planetary Motion, each planet orbits the Sun in an ellipse with the Sun at one focus.
The concept of focus is crucial for understanding how telescopes gather and concentrate light.
For elliptical orbits, there are two foci; one of these is occupied by the central body being orbited.
The distance between the foci determines the eccentricity of an ellipse, affecting orbital shape and behavior.
In reflecting telescopes, mirrors are shaped to bring incoming light to a focus, forming a clear image.
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Ellipse: An oval-shaped curve that describes the path of celestial bodies in orbit under gravity.