Apr 4, 2017

This is the Astronomers Alphabet. Today’s letter is “E.” “E” stands for “Earth” and “Ecliptic;” the ecliptic is the earth’s orbital path “E” means “Ellipse,” which is the shape of pretty much every orbit, including the Earth’s. Even circular orbits are usually a little bit elliptical, and the out-of-roundness of an orbit is expressed by another e word, “eccentricity.” The more elongated the main axis of the orbit, the greater the eccentricity, which causes an orbiting object to swing in real close to whatever it’s orbiting, and then shoots it far out away when it reaches the other side of the orbit. And “E” stands for “Einstein,” who came up with the formula, “E” equals mc squared, the formula that explains how the sun and other stars shine: through thermonuclear fusion, its Energy, or E, is equal to the mass of the material being destroyed times the speed of light squared, a really, really big number, which yields an astonishing amount of E, or energy!