OCR Text |
Show What Is the Sun Mado Of? It is generally agreed that the main body of tho sun tho nucleus within the photosphere must bo purely gaseous. This seems to be an unavolclablo conclusion conclu-sion from tho 6un'6 low moan density and its tremendous Internal temperature, which must almoHt certainly be far hlgh-or hlgh-or than that of Its outer surface; so high that oven the enormous force of solar gravity is able to compress tiio vapors to a density only one and four-teAths that of water, although among the constituent clemonta are many of tho metals (Iron being be-ing the most conspicuous) which ln the solid or liquid stale aro from thrco to eight times as dense. The render must not Imagine, however, that this gaseous nucleus nu-cleus is like air or other gases as we encounter en-counter them upon tho earth. Denser than water, and strongly viscous from tho heat, it more resembles a globo of tar except ex-cept near the outside. Thcro the vapors relieved from pressure aro frco to expand, ex-pand, and to cool both by tho cxpanslpn and by radiating heat to outer space, in a region of powerful currents, ascending, descending and cyclonic. The photosphere or luminous surface is generally believed to bo what It looks like ashcet of clouds enveloping the nucleus and consisting of minute drops and crystals crys-tals formed from thoso vapors which con-donso con-donso at tho highest temperatures, Theso clouds float In an atmosphere composed of tho permanent gases lie hydrogon and helium he-lium mixed with the more numerous vapors va-pors which condense- only at far lower temperatures than thoso that form tho clouds. As to the substances which compose com-pose the cloud-particles opinions aro unsettled. un-settled. Prof. C. A Young, ln Harper's Weekly. |