Rensselaer Republican, Volume 18, Number 44, Rensselaer, Jasper County, 8 July 1886 — The Zodiacal Light. [ARTICLE]

The Zodiacal Light.

The zodiacal light is the name given to a faint column of light which may be seen rising from the western horizon in clear mornings in the winter and spring, and from the eastern horizon just before daybreak in the summer and autumn. This light really extends out on each side of the sun, and lies nearly in the plane of the ecliptic or earth’s orbit. As the course of the ecliptic is, to dwellers in northern latitudes, very near the horizon during the summer and autumn, in those seasons the light is extinguished in the evenings by the thickness of atmosphere through which it must pass. Near the equator, where the ecliptic always rises high above the horizon, the light can be seen about equally well all the year round. It generally is seen to extend not more than 90 degrees from the horizon, but in a clear atmosphere, between the tropics, has been traced all the way across the heavens, forming a complete ring. This appearance was first called to the attention of astronomers by Cassini about 1683; and for many years the theory was that it was caused by the sun’s atmosphere. Laplace was the first to demonstrate that this idea was incorrect, and to advance the theory, now generally accepted, that the appearance is caused by minute meteoric bodies revolving around the sun. Examined in the spectrum, the light emanating from the zodiacal appearance is seen to show not distinct chromatic lines, but a continuous sheen, which shows it to be reflected light only. The orbits of this meteoric matter —for each fragment is supposed to travel in a path distinct from all the others—must be highly eccentric, which accounts for the noticeable difference in the appearance of the zodiacal light at different times.— lnter Ocean.