StNicholas [serial] . THE GARLAND-SELLERS IN THE HAWAIIAN ISLANDS. 752 NATURE AND SCIENCE FOR YOUNG FOLKS [June, COMETS Comets (the name comet is derived from aGreek word meaning hair) are heavenly bodieswholly different from all others known, and, insome points, are enveloped in mysteries that sci-ence has yet to penetrate. It has been affirmed that the heavenly space isas full of comets as the sea is of fishes. Onlythe brightest of these, however, are visible with-out the use of a good telescope. These easilyvisible ones differ little from one another in gen-eral appearance and consist of th
StNicholas [serial] . THE GARLAND-SELLERS IN THE HAWAIIAN ISLANDS. 752 NATURE AND SCIENCE FOR YOUNG FOLKS [June, COMETS Comets (the name comet is derived from aGreek word meaning hair) are heavenly bodieswholly different from all others known, and, insome points, are enveloped in mysteries that sci-ence has yet to penetrate. It has been affirmed that the heavenly space isas full of comets as the sea is of fishes. Onlythe brightest of these, however, are visible with-out the use of a good telescope. These easilyvisible ones differ little from one another in gen-eral appearance and consist of three parts—thenucleus, the coma, and the tail. The nucleus isthe bright, starlike tip; the coma appears as abit of luminous vapor surrounding the nucleus;while the tail trails away from the coma, always. DIAGRAM SHOWING A SECTION OF THE ORBITS OFHALLEYS COMET AND THE EARTH. The various positions show where each will be at certain dates. Theillustration also shows how the comet changes from a morning to anevening object. in a direction away from the sun, and graduallyfades away into the sky, like long hair blown outin the wind. The nucleus, the densest and most luminous part, is believed to be gaseous, and more distantstars may be easily seen through it with goodtelescopes. The great comet of 1680 was com-puted by Sir Isaac Newton to be exposed, whennearest the sun, to a heat 2000 times the temper-ature of red-hot iron —a temperature sufficient toturn to gas any substance known to man. Comets are believed to be tiny bits of the rawmaterial from which the planets were made, andto have wandered through space since the begin-ning of the solar system. One by one they areattracted toward the sun. Revolving around thesun in a curved path, their momentum carriesthem again into space, whence
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Keywords: ., bookcentury1800, bookdecade1870, bookidstnicholasse, bookyear1873
