OCR Text |
Show Spots on Sun May Cause Storms to Rage Over Earth By ALFRED RORDAME. Member Astronomical Society of the Pacific. A MOST, unusual disturbance is now taking place upon the sun. A group of spots covering cover-ing an area of over SQ.OuO miles square is visible at present making their transit across the solar surface. The group consists con-sists of two main snots, each having a nucleus of an intensely black a p-pearance p-pearance and are surrounded by penuinbrae of lighter hue. When a group of hpota of the se of those now on the sun show unusual un-usual activity at tile time the central cen-tral solar meridian I;; reached, they are usually, though not always, accompanied ac-companied by disturbances in t he magnetic field of the earth, causing aurorao and magnetic storms, interference inter-ference wiUi telegraphic communications, communica-tions, etc. If any disturbances accompany ac-company the present group of spots, the erfect. will make itself felt in a day or two. A maernpth storm may rage over the who.r rarth while the nun is ehining br't-'htl; , ;)nd muj-t not be confounded with th 50-called electrical storm accompanied by thunder and lightning, which is purely pure-ly local in character. The cause producing the sun spots 1b not very' well understood as yet. The tremendous force of gravity and the intense hea t that prevails upon the sun make conditions there almost inconceivable in-conceivable to us upon the earth. The sun consists principally of a mass of heated metallic gases, but this gas and vapor exist there in the form of a fluid of the consistency of honey or tar, due to the enormous pressure exerted by gravity. The luminous surface of the sun or photosphere, as it is called, consists con-sists principally of clouds of calcium, hydrogen and tno lighter elements, while the heavier metals, like iron, boll up or are forced throueh the luminous shell by the tremendous diminution of upward pressure, and the photosphere sinks somewhere in t lie neighborhood, causing a shallow, irregular cavity to be formed. The materials t brown out by the eruption are cooled in the upper regions of the sun's atmosphere, and f a 1) back into the cav i ty . The light from below struggling i hrough this com para lively coo vapor is dimmed by absorption, and looks bla.'"k by cont ras t with the inten&e.ly brlllia nt. fnrfaoe of tho sun's phAtosphtTr. TV. a t the ,i p o t s are not rra.ll v bine', though they nem o, may he proved by superimposing an electric arc light upon the da'-kest part of a sun spot. The arc shows up a still more Intense black. |