Maxwell's equations for Electromagnetism are a set of four coupled partial differential equations that, along with the Lorentz force law, form the foundation of classical electromagnetism.

Originally developed by James Clerk Maxwell in the 19th century, the equations were later condensed into their modern vector calculus form by Oliver Heaviside.

Earth's core, which is about the size of Pluto, is the same temperature as the surface of the Sun.

The Doppler effect is the change in the frequency or, equivalently, the period of a wave in relation to an observer who is moving relative to the source of the wave. It is named after the physicist Christian Doppler, who described the phenomenon in 1842.

Kepler's three laws of planetary motion describe the movement of planets around the Sun.

First Law: Planets orbit in ellipses with the Sun at one focus. 

Second Law: A line segment joining a planet and the Sun sweeps out equal areas in equal times. 

Third Law: The square of the orbital period is proportional to the cube of the semi-major axis. 

Johannes Kepler formulated these laws, which were fundamental to understanding orbital mechanics.