When a new child visited our Sunday school, the teacher greeted him and asked his age. The little boy held up four fingers.
"Oh, you're four," said the teacher. "And when will you be 5?"
The child stared at her and after a few seconds replied, "When I hold up the other finger."
Saturn's ringsIn 1895, a spectrogram made by American astronomer James Keeler proved that the rings of Saturn were indeed composed of meteoric particles, as predicted by James Maxwell. If the rings were solid, observations would show uniform rotation. However, Keeler's spectrogram of light reflected from Saturn's rings showed a Doppler shift indicating a variation in radial velocity. Thus, particles in the inner part of a ring, closer to Saturn, move at a different rotational speed from those in more distance parts of a ring, as predicted by Kepler's 3rd law. Keeler publishedA Spectroscopic Proof of the Meteoric Constitution of Saturn's Rings in the May 1895 issue of Astrophysical Journal, vol. 1, p.416, the journal he co-founded with George E. Hale.«[Image: artist's illustration of Saturn's rings] |
