Name. Diameter in miles. Jupiter 90,000 Uranus 35,000 The Earth 7,926 Mercury 3,000 The Moon 2,160 Rhea, Saturn's 5th satellite 1,200 Dione " 4th " 500 Vesta[10] 260 Juno 104 Melpomene 52 Polyhymnia 35 Isis 25 Atalanta 20 Hestia 15 The diminution doubtless continues indefinitely below the present limit of optical power. If, however, the orbits have small eccentricity, such asteroids could not become known to us unless their mean distances were nearly the same with that of the earth. But from the following table it will be seen that the variety is no less distinctly marked in the forms of the orbits: Name. Eccentricity. Venus 0·00683 The Earth 0·01677 Jupiter 0·04824 Metis 0·12410 Mercury 0·20562 Pallas 0·24000 Polyhymnia 0·33820 Faye's comet 0·55660 D'Arrest's " 0·66090 Biela's " 0·75580 Encke's " 0·84670 Halley's " 0·96740 Fourth comet of 1857 0·98140 Fifth comet of 1858 (Donati's) 0·99620 Third comet of 1827 0·99927