Show I 1 the Di distance stanco of the star the distance of the star alpha may maybe be stated in round lound numbers to be of miles now a billion means a million of millions so that the distance ot of alpha may bo be A stated ted to be twenty mil millions Horis of millions of miles let us now try to 0 o form some eption however impel feet fee Z of the amazing stance let us suppose a railway train to eave the earth traveling day and night it the rate of fifty miles nn an hour without in ill six mouths months it would reach the moon in ye years ars it would reach the un still and in 3 bears ears 1 ii would reach the innet 1411 let neptune the orbit of which forms forma the extreme known limit of the planetary system the same train however would not act reach the star alpha I 1 in less lesa han ian years one more may bo be use useful f u 1 comets in general revolve in very eccel rc orbits when an a comet is in the perihelion of its orbit it Is comparatively near 0 o the earth on oil the other hand ban when it is nt at the aphelion it is remote in many instances is very remote from tile the earth vor instance the celebrated comet of 1858 known as donatila JUon Dona comet one of the greatest comets of modern times at the dac of its passage of the perihelion was distant from the sun miles but IT lien it has attained the aphelion aphelia n of its orbit r bit which will occur in about 1000 years vears hereafter its distance f from rom the earth will not be less than miles now our typical railway train starting star tins f from rom the earth would not reach the aphelion of the orbit of donatis comet in loss less than GO CO years and yet the aphelion distance of 0 donatis comet is only one hun bun arenth part of the distance front from the lie earth to alpha the tha nearest of the fixed stars good words |