from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Plural form of perihelion.
Sorry, no etymologies found.
The traverses change all the time, depending on the perihelions and aphelions of individual asteroids.
It is true that a mass of matter driven from the sun cannot be exactly compared to a globe which touches its surface, for the impulse which the particles of this mass receive from one another and the reciprocal attractions which they exert among themselves, could, in changing the direction of their movements, remove their perihelions from the sun; but their orbits would be always most eccentric, or at least they would not have slight eccentricities except by the most extraordinary chance.