Only four asteroids large enough to be measured--Remarkable differences in their brightness irrespective of size--Their widely scattered and intermixed orbits--Eccentric orbit of Eros--the nearest celestial body to the earth except the moon--Its existence recorded by photography before it was discovered--Its great and rapid fluctuations in light, and the curious hypotheses based upon them--Is it a fragment of an exploded planet?--The startling theory of Olbers as to the origin of the asteroids revived--Curious results of the slight force of gravity on an asteroid--An imaginary visit to a world only twelve miles in diameter CHAPTER VI _JUPITER, THE GREATEST OF KNOWN WORLDS_ 160 Jupiter compared with our globe--His swift rotation on his axis--Remarkable lack of density--The force of gravity on Jupiter--Wonderful clouds--Strange phenomena of the great belts--Brilliant display of colors--The great red spot and the many theories it has given rise to--Curious facts about the varying rates of rotation of the huge planet's surface--The theory of a hidden world in Jupiter--When Jupiter was a companion star to the sun--The miracle of world-making before our eyes--Are Jupiter's satellites habitable?--Magnificent spectacles in the Jovian system CHAPTER VII _SATURN, A PRODIGY AMONG PLANETS_ 185 The wonder of the great rings--Saturn's great distance and long year--The least dense of all the planets--It would float in water--What kind of a world is it?--Sir Humphry Davy's imaginary inhabitants of Saturn--Facts about the rings, which are a phenomenon unparalleled in the visible universe--The surprising nature of the rings, as revealed by mathematics and the spectroscope--The question of their origin and ultimate fate--Dr. Dick's idea of their habitability--Swedenborg's curious description of the appearance of the rings from Saturn--Is Saturn a globe of vapor, or of dust?--The nine satellites and "Roche's limit"--The play of spectacular shadows in the Saturnian system--Uranus and Neptune--Is there a yet undiscovered planet greater than Jupiter? CHAPTER VIII _THE MOON, CHILD OF THE EARTH AND THE SUN_ 212