It has long been known that the Earth's magnetic pole reverses polarity every 200,000 years or so, however the precise cause of this switching has been unknown to scientists despite major advances in modern technology.
The last such reversal - which generally takes a number of years to complete, and as evidenced by the polarity of basalt flows which can be geologically dated - took place about 780,000 years ago.
Accordingly, we are long overdue for the experience, but are yet to see any indications of the next reversal.
However, a recent discovery claims to provide undisputable evidence that the reversals are actually triggered by explosive events in an obscure and far off object known as Polarissima Australis (ESO 001-G001), a small galaxy in the Southern constellation of Octans.
This “Holy Grail” was discovered by Sir John Herschel at the Cape of Good Hope with an 18" ƒ/13 speculum telescope.
He recorded it as "Neb. Polarissima Australis. Faint, round, gradually a little brighter in the middle, 25 arcsec across. Situated nearly halfway between a star of 10th magnitude south of it, and a small triangle of stars 11th, 13th and 13th mag. north."
Herschel had made this discovery on one of those rare occasions that he had actually been doing some serious observing instead just of making a buck by casting horoscopes for the rich Boer merchants and farmers in and around Capetown.
Having been careful to make only long term astrological forecasts, Sir John was safely away and back in England long before the forecasts were due to take place - or not, as the case may be.
Polarissima Australis had been the subject of intense study at the Bogong High Plains Observatory using the SPeckle InterFerometer (SPIF) binocular radio telescope dish in the Victorian High Country.
This instrument had been fine-tuned to detect three-dimensional radio echoes superimposed against the background microwave radiation in the Universe and is now capable of detecting radio echoes of historical major events and in ellipsoid mode tracing such events back to their respective epicentres.
Fine-tuning of the binocular radio telescope was effected by tracing the supernova event which gave rise to the Crab Nebula in Taurus and thus completing the calibration process which had commenced whilst tracking the 19th century nova outburst in Eta Carina. Both these events could be accurately dated from the historical record.
"The Bogongs", as the staff were affectionately known, were surprised to record a whole sequence of massive events emanating from Polarissima Australis of such scale and magnitude that they could only be interpreted as a series of gamma-ray bursters.
Though the present instrument is only capable of recording such events as far back as 2.26 million years, the most exciting aspect of the discovery was that each event exactly coincided with the reversals of the Earth's magnetic field as recorded in the geological basaltic record over the same time period.
Although the distance at which the galaxy is located is so great that any known gamma-ray bursts would not have caused significant injury to our planet, the bursts must have been precisely focussed - perhaps by the lens-like shape of that galaxy being angled in our direction - to allow the intensity to be of sufficient magnitude to affect the Earth's magnetic field so profoundly.
As it has been so long since the last reversal, with the "next" one now overdue by about 580,000 years, it may be that the number of potential supernova-prone stars in that galaxy must be exhausted, or at least greatly reduced.
Research into Polarissima Australis continues and further results will be published in Alternate Universe in coming issues.