CELESTIAL MIDGETS

Evening Post, Volume CXV, Issue 103, 4 May 1933, Page 9

CELESTIAL MIDGETS

STORY OF THE PLANETOIDS

SOME. STRANGE FACTS

An amusing story is told oJ' Sit George Airy (for many years Astro uc mor Royal of England)-when In eom.mand of Greenwich Observatory in Mid-Victorian day, writes "An Astronomer" in the Sydney "Daily Tele- , graph." Airy was a martinet vrhero his assistants were concerned, and possessed to an extraordinary degree tho "•official'' mental outlook. Coming into the observatory one night he- found an assistant working after his regulation hours were over. Dragging hint from the telescope, he demanded tlio meaning of this breach of regulations. The unfortunate assistant - stammered, that ho was searching for minor planets t f ■ Airy rated him violently, and threatened him with dismissal for his revolutionary behaviour; it is said that no one at Greenwich under the Airy reghuo attempted the crime of discovery afterwards. Those wcto the great days of discov* cry for minor planets or asteroids, tha multitudes of tiny planetary fragments which swim' between the orbits>of Mars and Jupiter. They were once believed to be remnants of a planet which either exploded or collided with some celestial object; but nowadays it is believed that the attraction of Jupiter prevented the matter in this region coalescing to a single sphere. Had the planet formed, it would have bflen the smallest in tho. system, hardly as large as the .moon. Some of Jupiter's tiny outer satellites are probably asteroids which tho giant globe has captured in the past. Tho larger asteroids were all discovered early in the nineteenth ccntuiy, and during that period a certain fainu attached to vthcir discovery. But nowadays, when only tiny planetoids a few miles in diameter remain to be found, the romance has vanished, and they are trapped prosaically by their trails ou photographic plates. The 1000 mark was passed in 1924. At .present about 300 more have been added (it takes .<. long search of1 past records to rnako sure a discovery is really new). Kaming those little planets has be* come a stiff job., At .first tho discoverers kept to classic mythology. Th» first half dozen were Ceres, : Pallas* Juno, Vesta, Astraea, and Hebe. But soon classical versions of reigning potentates ' names began to be brought inj such as Maximiliana; and later it became the fashion to christen . theso specks by the name of a relation or "best girl," such as Beatrix, Johanna, Miriam, May, Charlotte, Anna, and Hilda. For a time cities.got a piano- , tary namesake ' (Chicago, Princetonia, Pittsburghia); arid,' lately gardeners have taken a hand, (four recent ones are Begonia, Camellia, Petunia, and, Primula). ■ ' » / NAME PUT UP FOR AUCTION. On© minor planet's name was evert put up for auction, the seller being; Professor Palisa, a prolific discoverer, who "needed, funds to carry on his work. The offers did not come at once, so ho named this speck, and kept the .auction open for two later discoveries. Ouo of the Bothschilds then bought the last one fon£so, and named it Bettina. -Certain asteroids stand out front the 'ruck, for peculiarities of appearance .or orbit. -Vesta (one of that largest, though only 250 miles in diameter) has a puzzling brilliance, sug« gesting an atmosphere.. But it is far, too small-to retain one,-and it,is coni jecturcd that it is just a piece of whitoj stone f (like marble floating in space), .Others show periodical waxing and waning, of light, andj on the theory that this is due to-irregularity-of surface their axial rotations have, been calculated. With some the light-variation suggests that tho asteroid is of dumb-bell shape, or may be two irregular masses. Eros is one of these. '' Eros is three times us dense as. thai earth, and nine times as bright as tii<* moon; hence it might bo a twin mass cither of heavy metal or shiny metallic ore. Till recently it was thought to bo (Qn occasion) the nearest planet to the earth; owing to the eccentricity of its orbit it approaches to within, half tho distance of Venus, and, though only; 20 miles in diameter (across the dumbbell), it becomes visible in a pair of! field-glasses. The- last near approach was in 1931. Another speck (3 mile* in diameter) named Albert comes as close; but last July a German observer; found a midget which approaches ua . closer than either, getting right in* side our orbit, and so closer to the sun. It is a jagged mass of dully-reflecting rock, only a mile or so across. Life (as we know it) seems impose sible on these floating specks, because) they cannot retain oxygen or water; vapour, which would fly off into space. If, by any chance, a human being equipped with oxygen apparatus could land on one of the smaller asteroids, ha, could hardly take a step without losing I his footing, owing to the low force of gravity, and a leap might take him out of. its pull altogether, to travel space like a human comet till ho died. Even on the largest, Ceres, the force of g'rav« ity is only one-thirtieth of that on thai" earth. It has been suggested that minute animals and plants might live in! pools of water occluded (closed in)' within the asteroids, getting oxygen' •and carbon dioxide by breaking dowii oxides and carbonates contained in miai erals,'but this is unlikely. ■