| At the second, Encke's comet and all others with perihelia within Mercury's orbit would have shared a similar fate. |
| This tendency of the perihelia to crowd together in two opposite regions has been noticed by different writers. |
| Secular resonances, in which two orbits interact through the motions of their ascending nodes, perihelia, or both, operate over timescales of millions of years to change the eccentricity and inclination of asteroids. |
| The extremes of temperature at perihelia and aphelia to which comets are subjected did not bother him particularly. |
| These three groups have more distant perihelia than the Kreutz group and many objects survive perihelion. |
| The maximum occurs between 30 and 60, where thirty-five perihelia are found in 30 of longitude. |
