Mathematics and Physics Glossary

e, n. (Math.) The base of the natural system of logarithms, having a numerical value of approximately 2.7183.

Eagle n. (Astron.) A northern constellation, containing Altair, a star of the first magnitude. See Aquila.

Earth’s mass, n. (Astron.) 5.977 × 10²⁴ kilograms.

Earth’s radius, n. (Astron.) mean radius of the earth is 6.371 × 10⁶ meters.

Earth-to-moon distance, n. (Astron.) mean distance is 3.844 × 10⁸ meters.

Earth-to-sun distance, n. (Astron.) mean distance is 1.496 × 10¹¹ meters.

Earth battery (Phys.), a voltaic battery the elements of which are buried in the earth to be acted on by its moisture.

Earth light (Astron.) The sunlight reflected from the earth to the moon, by which we see faintly, when the moon is near the sun (either before or after new moon), that part of the moon's disk unillumined by direct sunlight, or "the old moon in the arms of the new." -- called also earth shine. Sir J. Herschel.