What precipitates manna from heaven?


IF you were walking down the road and suddenly a shower of frogs rained down upon your head you would be pardoned for thinking that you had unwittingly strayed into the drama of a child's fairytale.

Unusual falls such as these do occur and are well documented. Most of them can be understood and explained as the result of natural phenomena.

A wide variety of substances that would seem to have no sensible business in being aloft have been reported falling to Earth. These include fish, frogs, snails, shellfish, worms, snakes, hay, seaweed, cobwebs, manna, meat, seeds, nuts, berries, gelatin, sand, cinders, coal and salt.

Reports of falls are not restricted to any particular area, but come from all over, including Ireland. A further unusual feature of most of these incidences is the relative purity of each fall, i.e. a fall of frogs, for example, usually consists of nothing but frogs.

The obvious question that arises with regard to these unusual falls is how this material gets up into the atmosphere in the first place. For many years the scientific community took little serious interest in reports of falls, but in recent years, the matter is receiving more serious attention.

The favoured explanation of the mechanism that lifts the objects into the atmosphere is the whirlwind and its more violent expression, the tornado (cyclone, twister).

Whirlwinds and tornados act like vacuum cleaners, sucking up loose material, carrying it for miles and then depositing it on amazed citizens. A tornado occurring over a river or sea sucks up water and is called a waterspout. Waterspouts can suck up fish. The suctioning power of a tornado is dramatically illustrated in the film Twister, now showing in the cinemas.

Hay is probably the most common material transported by whirlwinds and the phenomenon is familiar to many farmers. A neighbour of mine told me how he once saw whirlwinds lift up small cocks of hay, layer by layer. The hay rose several hundred yards into the air and was then quickly carried away laterally until it bumped into a hillside some miles away.

The whirlwind/tornado/waterspout theory is a plausible mechanism to account for unusual falls. However, some authors feel that a weakness of the theory is that it does not account for the characteristic "purity" of most of the falls.

How could a tornado coming on a marshy pond selectively lift only the frogs from the ground and leave behind all the other things plants, mud, twigs, leaves etc?

Of course, the tornado would not selectively lift the frogs and leave the rest behind all would be lifted. However, it might be expected that as the diverse mixture is carried through the air the various components would segregate out from each other according to weight, size, shape etc. This phenomenon is totally familiar to every scientist who has ever used a centrifuge.

Christians and Jews are familiar with the Old Testament account of manna falling from the sky to sustain the Israelites during the exodus from Egypt. Several scientific investigations have been carried out in order to construct a natural explanation for the manna.

Investigation of the phenomenon is facilitated by the fact that falls of manna continue to occur occasionally in the Middle East. Manna means the fall of any whitish substance having some nutritional value.

Apparently manna can have several sources. In 1890 a heavy fall occurred in Turkey, where it was collected and used to make bread which is reported to have been of good quality.

The manna consisted of small spheres which, upon examination by botanists, were found to be composed of lichen. The lichen is found mainly on arid mountains in eastern Europe and in Asia. It is thought to have been transported to Turkey by a tornado.

Falls of manna can also have other sources. A detailed investigation carried out by the Hebrew University of Jerusalem in the Sinai peninsula discovered that the appearance of manna is a well known phenomenon in the region and is caused by excretions of insects that live on desert shrubs. The dry desert atmosphere causes the fluid excretions to crystallise and the resulting white grains fall to the ground.

I have only found a few references to unusual falls in Ireland. Charles Fort, an American journalist, has collected and published many accounts of strange objects falling from the sky.

One very intriguing Irish fall reported by Fort occurred in Munster and Leinster in 1695. This was recalled by Father Donal O'Driscoll in a letter to the Evening Echo of March 10th, 1989. The material that fell was described as "soft, clammy and of dark yellow colour". It fell in lumps "as big as the ends of one's, fingers" and was called "butter" by the country people. It had a strong, bad smell.

The other two Irish falls that I have seen mentioned are more prosaic. One was of hay recorded in 1875 at Monkstown, Co Dublin. The other was a peculiar fall of berries that fell in the city of Dublin in 1867.

They were reported as being about half an inch in diameter, black in colour and, when cut across, seem as if made of some hard dark brown wood. They also possess a slight aromatic odour". The berries "fell in great quantities and with such force that even police, protected by unusually strong head covering, were forced to seek shelter from the aerial fusillade."

Many readers will recall unusual falls of fine reddish dust that have occurred in Ireland in recent years. The most extensive fall in recent times occurred on November 28th, 1979. Several have been recorded in Ireland since 1979. The most notable before 1979 was recorded in 1903.

At UCC I have studied the nature, composition and origin of these dust falls in collaboration with Dr Peter Vernon, of the Geology Department, and with the assistance of Ms Myriam Cotter. Professor B. Hathaway and Mrs K. Duggan, of the Chemistry Department, UCC also collaborated with us in the study of the 1979 fall.

Our conclusion is that the dust is mainly composed of extremely fine sand grains (the average grain is about one millionth of a metre wide) that have been carried here from the Sahara desert.

These very fine grains are driven high into the atmosphere by turbulent winds during desert dust storms. Once aloft they can be carried for very large distances before falling back again to Earth.

The prevailing winds usually carry the dust westwards over the Atlantic towards the West Indies. However, under certain meteorological conditions the dust can be carried northwards over Europe. These conditions are a high pressure area over France and/or Spain and an intense low pressure zone over the Atlantic.

This results in strong north easterly winds bringing air up from the south west. Whenever such conditions intercept dust moving westwards from the Sahara, a dust fall is likely in northern Europe. Such weather conditions have always coincided with dust falls in Ireland.

As can be seen, the range of terrestrial materials known to fall occasionally from the sky is very diverse. There seems to be no need to invoke any hypothesis other than tornados/waterspouts and turbulent winds to account for the phenomenon.

As for material of extra terrestrial origin falling to earth, possibly the most important such fall ever was the meteorite from Mars recently analysed by NASA, which suggests that life once existed on that planet. I will return to that matter in the near future.