Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 29, 2025
The case brought to mind a warm discussion between Hansen and Encke, in the pages of a scientific journal, some fifteen years before. At the time it had seemed intensely comical to see two enraged combatants for so I amused myself by fancying them hurling algebraic formulæ, of frightful complexity, at each other's heads.
Halley's comet remained the only one of which a prediction of the return had been confirmed, until the orbit of the small, ill-defined comet found by Pons in 1819 was computed by Encke, and found to have a period of 3 1/3 years. It was predicted to return in 1822, and was recognised by him as identical with many previous comets.
On the 26th of November, 1818, Pons of Marseilles discovered a comet, whose inconspicuous appearance gave little promise of its becoming one of the most interesting objects in our system. Encke at once took the calculation of its elements in hand, and brought out the unexpected result that it revolved round the sun in a period of about 3-1/3 years.
Encke followed at Berlin with a still more elegant method; and Sir John Herschel, pointing out the uselessness of analytical refinements where the data were necessarily so imperfect, described in 1832 a graphical process by which "the aid of the eye and hand" was brought in "to guide the judgment in a case where judgment only, and not calculation, could be of any avail."
What Encke stipulated for was not a medium equally diffused throughout the visible universe, such as the ethereal vehicle of the vibrations of light, but a rare fluid, rapidly increasing in density towards the sun.
The great ring north of Flamsteed, 60 miles across, is a notable example; another lies west of it on the north of Wichmann; while a third will be found south- east of Encke; indeed, the Mare Procellarum abounds in objects of this type.
It was not even known how closely some of them are enchained until the German astronomer Encke, in 1822, showed that one which he had rediscovered, and which has since borne his name, was moving in an orbit so contracted that it must complete its circuit in about three and a half years.
The second of these bodies to affect a looked-for return was a comet the sixteenth within ten years discovered by Pons, July 20, 1812, and found by Encke to revolve in an elliptic orbit, with a period of nearly 71 years. It was not, however, until September 1, 1883, that Mr. Brooks caught its reappearance; it passed perihelion January 25, and was last seen June 2, 1884.
Word Of The Day
Others Looking