A little ramble through 19th century astronomy- On the Great Sunspot of June 1843

 From the ‘American Journal of Science and Arts vol 1 April 1871

On of the largest and most remarkable spots ever seen on the Sun’s disc appeared in June 1843 and continued visible to the naked eye for seven or eight days. The diameter of the spot was according to Schwabe 74,000 miles; so that its area was many times that of the Earth’s surface.

Now it has been observed during a number of sunspot cycles that the larger spots are generally found t or near the epoch of the greatest numbers. The year 1843 was however a minimum epoch of the eleven-year cycle. It would seem therefore, that the formation of this extraordinary spot was an anomaly, and that its origin ought not to be looked for in the general cause of spots of Schwabe’ cycles.

As having a possible bearing on the question under consideration, let us refer to a phenomenon observed at the same moment on the 1^st September 1859, by Mr Carrington at Redhill and Mr Hodgson at Highgate. Mr Carrington had directed his telescope to the Sun, and was engaged in observing his spots, when suddenly two intensely luminous bodies bust into view onto its surface. They moved side by side through a space of about thirty-five thousand miles, first increasing in brightness, then fading away. In five minutes, they had vanished… It is a remarkable circumstance that the observations at Kew show that on the very day, and at the very hour and minute of this unexpected and curious phenomenon, a moderate but marked magnetic disturbance took place, and a storm or great disturbance of the magnetic element, occurred four hours after midnight, extending tom the southern hemisphere.

The opinion has been expressed by more than one astronomer that this phenomenon was produced by the fall of meteoric matter upon the surface of the Sun’s surface. Now the fact nay be worthy of note that the comet of 1843, which had the least perihelion distance of any on record, actually grazed the solar atmosphere almost three months before the appearance of the great comet of 1843. The comet’s least distance from the Sun was almost 65,000 miles. Had it approached but little nearer, the resistance of the atmosphere would have probably brought its entire mass to the solar surface. Even at its actual distance it must have produced considerable atmospheric disturbance.

But the recent discovery that a number of comets are associated with meteoric matter, travelling in nearly the same orbits, suggests the inquiry whether an enormous meteorite following in the comet’s train and having a somewhat less perihelion distance may not have been precipitated upon the Sun, thus producing the great disturbance so shortly after the comet’s perihelion passage/

Daniel Kirkwood, Bloomington, Indiana

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