Confirmation of this strange phenomenon has come from as far south as the radio physics observatory at the South Pole, and Mr Ivor Merino’s complex on the frozen summit of Mt. Cook in New Zealand to classic observatories such as Lick and Palomar.
Astronomers had long been familiar with the retrograde motion of Mars as it varies between perihelion and aphelion, with the Earth overtaking on the inside track as it were and making the planet appear to reverse its course against the background stars.
In ancient times and in the middle ages, this phenomenon caused endless headaches for astronomers and philosophers desperately trying to make the Ptolemaic system work, with epicycle upon epicycle added to try to find some “perfect“ explanation.
Curiously enough, it seems that this year we are to see the same phenomena occur in connection with Earth’s own satellite, the Moon, a rare cyclical event concerned with a cumulative effect of a prime number of transits of Venus.
Though Venus is quite small in diameter compared to the Sun, during transit it causes a minute but measurable diminution in the Solar radiation reaching both the Earth and the Moon.
Light, of course, exerts a force – the Solar Wind and all that, and the end result of a certain number of transits is that in a manner analogous to precession, a coriolis effect is set up between the Earth and the Moon amplifying the echo of Earth’s oceanic tides on the Lunar Maria.
This causes a distinct precessional motion on the Moon, which will not only wobble sufficiently that over a period of only one Lunar month amateurs will be able to observe 78% of the Lunar surface, but as well the braking effect will temporarily throw the Moon into a wider and slower orbit, so that it will appear to reverse it’s course amongst the stars.
Though this will be the first such event anticipated and observable with high tech instrumentation, fragments in romantic ballads of the court of Elizabeth Tudor and Duke William the Bastard which were attributed to poetic licence and fantasy may well have a basis in observation by somebody.
Lines such as “My love doth stay the Moon’s majestic course”, and “Thy brilliant orb returns upon her tracks to mock my ill starred love”, written in the 16th century by balladeer Johan Sebastian Amadeus are dated to just after the last Lunar retrogression, computed to have occurred in 1592.
If the next such event takes place as forecast, the Moon will appear to stop and go into reverse very late in the evening of March 31, 2006.