SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 37 
PHYSICS OF THE SHOOTING STARS 
J. F. Lanneau, Prof. Math. & Science, Wake Forest College, N.C. 
Everyone is familiar with the suddenly bright, star-like ob- 
jects which swiftly and silently dart here and there in the 
evening sky every few minutes. These transient and seem- 
ingly erratic meteors are popularly known as shooting stars. 
In Ptolemy’s Almagest—written in the second century of 
our era, the authoritative text on astronomy for fourteen hun- 
dred years, taught onee even in Harvard and Yale—there was 
no mention whatever of shooting stars. They were held to be 
mere exhalations from the earth—of no concern to an astron- 
omer. But found to be truly celestial bodies, their study has 
become in recent years a specialty with some astronomers. 
By physies of a shooting star is meant such facts as its height 
above the earth, its distance from the observer, its mass or 
weight, and other seemingly unattainable knowledge concern- 
ing it. 
It is proposed to show in outline how such knowledge may be 
eained. 
Height, Distance, Velocity 
Two observers—one say near Wake Forest and one thirty- 
five miles due south, near Selma—-aegree to watch the western 
sky every fair evening until nine o’cloek. Many of the little 
meteors carefully noted by one of the watchers are not observed 
by the other. 
One evening however, as subsequently shown by comparing 
records, they both note the same shooting star seen to pass from 
the point s to the point s’, Fig. 1. 
Each observer counts rapidly while it shoots from s to s’. 
At the same time he notices the particular fixed stars nearest 
in hne with its appearance and disappearance at s and s’—the 
stars at r and r’ as seen from W, and the stars t and t’ as seen 
from L. This mueh quickly done, each looks at his wateh to 
see the hour and minute of the oceurrenece. Then, by several 
repetitions of his rapid count, wateh in hand, he finds the num- 
ber of seconds in the transit from s to s’. 
Their records, say, are: 
—At L— —At W— 
Count 23; Time, 5% see. Count 26; Time, 6% see. 
From Castor, (star beyond s) From a Hydra, (star beyond s) 
To Capella, (star beyond s’) To Procyon, (star beyond s’) 
Date May 1 ’05, 8:30 0’e. p.m. Date May 1 705, S:29 o’c. p. m. 
The two sets of notes agree substantially, as they should, in 
