We know less about Mercury than about any other planet except Pluto.

One of the big surprises of the space program was the discovery that Mercury had a magnetic field. Various theories have been advanced but all of them are problematic.

Mercury's rotation has always been a mystery to astronomers. For almost a century the finest astronomers in the world agreed that Mercury kept the same face pointed to the Sun and rotated about its axis in 88 days. Since Mercury has no atmosphere and is heavily cratered one would expect it to be relatively easy to determine this planet's rotation period since features on its surface are always visible. And yet, it was only in 1965 when radar was used that Mercury's actual axial rotation was determined to be 58.6 days. This caught everyone by surprise. How is it possible that Mercury's rotation could be such a mystery? Scientists keep likening Mercury to the Moon with its craters and its dormant surface. Determining Mercury's rotation period should be as simple as picking a single bright or dark spot and monitoring it for a period of time. But in almost a century not a single astronomer came even close to the real figure. Why?

Mercury is not quite as dead a world as it appears to be. NASA satellite photos show it to look almost exactly like the Moon, but the reports of astronomers, professional and amateur alike tell a whole different story. Mercury's surface is constantly changing. In the 1920's the great astronomer Antoniadi, made a convincing case that Mercury not only had an atmosphere but clouds also which were affecting the visibility of its surface. Many astronomers have commented over the years at the surprisingly fast changes which take place on the planet's surface. No one has ever explained this.

A bigger surprise occurred in the early 1990's when radar now picked up something new. Ice at its polar caps! This was surprising because the NASA Mariner photos from 1974 show no ice. So scientists concluded that the ice lay under a thin layer of dust, and had been there for billions of years. Nice theory that, except it flies in the face of drawings done by many astronomers over the years which show Mercury's surface changing in brightness. Sometimes Mercury's polar caps become exceptionally dark to the point of disappearing from view completely. At other times these same polar regions light up and become the brightest part of the planet. Richard Baum, (Director of the Mercury & Venus sections of the British Astronomical Association), has often commented on this. In the 1990's he wrote of instances in the past where astronomers drew very obvious ice caps on Mercury which then waxed and waned as the planet rotated. Is the ice at the poles really billions of years old or are there dust-storms and ice-falls taking place all the time on Mercury? Richard Baum openly tells other astronomers to study Mercury because it is not as dead a world as the textbooks would have us believe.

Observations of Mercury during its transits across the face of the Sun add to the picture of a temporary atmosphere which comes and goes. Indeed, as one studies Mercury's atmospheric phenomenon one realises that its atmosphere must indeed be temporary. Could Mercury be hollow? Could it be that air leaks out of the planet's polar regions by way of Polar Holes? Mercury's polar regions are the most variable areas of all changing from being very bright to being very dark. Could this be because of dust-storms caused by air coming out of the planet which then causes snow-falls? And what then? Does the air leak back into the planet and remain there? Does an Inner Mercury undergo various weather phenomenon which cause air to be expelled on to the outer surface and which later returns inside?

The last thing one expects is water in an atmosphere on Mercury, and yet, the evidence suggests that moisture-laden air is expelled from inside Mercury on to its outer surface and this may be the cause of all the strange weather phenomenon seen on that planet.

Does Mercury have Polar Holes in its polar regions? The nature of the weather phenomenon leads me to believe this is so. Why then do the Mariner photographs show us nothing? Or is it that NASA actually edits these photographs? I would strongly urge astronomers to look into the issue of discrepancies between NASA's photographs of the polar regions of Mercury and the subsequent sightings dating back more than a century showing the polar regions of that planet waxing and waning. Recent drawings (1997) published in the British Astronomical Association Journal show the polar regions of Mercury to be the brightest part of the planet. Is that because a polar ice cap is sitting there in full view for all to see?