Thursday, December 3, 2015

A Visit to Mars (part 2)

Map of Mars (1894)
More from  the Dutch astronomer, Professor G. Van den Bergh  ‘A Visit to Mars ‘ a chapter in his The Universe in Space and Time (1935). In this account, which has weird parallels with the adventures of the Matt Damon character in the recent movie The Martian ‘a man, an inhabitant of the earth, succeeded in reaching Mars by rocket. He remained there a few years and evidently managed to keep alive, thanks to his good equipment and a large stock of provisions’. After a while this man returned to Earth, but was killed when his rocket crashed. It transpired that the man had kept a diary, but only a few pages could be rescued from the crash site, some of which were reproduced in the chapter. This continues an earlier jot.

October 45. It was again very fine today. And from an astronomical view point of view it was a very remarkable day. It as amazing, I was dumfounded. I shall never forget the sensation.
But I must try to put things down in an orderly fashion as one should do in a proper diary. To continue, the sun was again shining brightly in the sky, as it nearly always does here. I happened to be watching it through my telescope. A fine group of sun-spots was visible.
Then a small solar eclipse started. There was nothing peculiar in that. We see some 1,400 eclipses here every year caused by Phobos, and about 130 caused by Deimos. A day without an eclipse would therefore be more remarkable than a day without one…Today I in the first place had the privilege of seeing a compound solar eclipse. These are quite rare. Exactly at the moment Deimos was half-way on its passage across the sun, Phobos shot across  for some seconds, covering both Deimos and part of the sun. This alone would have been sufficient to make the day a very special one for me from an astronomical point of view. But a far more remarkable thing was to present itself to my eyes. As I was watching the sun through my telescope, I saw a very small black body appear at the edge of the solar disk; some minutes passed before it was silhouetted entirely against the sun. It could not be Venus. I had seen Venus last night shining as the evening star in the Western sky! Then it must be Mercury?
It first sight this tallied rather well with the dimensions it should have. The black spot slowly travelled farther in its course across the sun. I followed it with great attention. To my great surprise a much larger disk appeared after some time at the edge of the sun, and this disk required even longer to make its full appearance against the sun. Then suddenly, with a shock, I realised what they were; how could I be so stupid as not to understand at once! For I knew that the Earth was at inferior conjunction, so I should have realised that a transit of the Earth across the sun was at least possible. Indeed I was right, it was the Earth and the moon outlined against the sun!
A rare sight, which I had the good luck to witness, and which happens twice a century on Mars. On they travelled, very slowly. The Earth with all its strife, its feuds, its pride, as a small, very dark spot  passing in front of a solar disk.

 December 34. I am now on the edge of the South Pole cap. It is about summer solstice. Not very much is left of the polar cap. Three, four months ago it extended as far as 60 degree Lat. (S). At this part of the year only a small part of it is not evaporated by the heat of the sun. As soon as the temperature rises to –60 degree the hoar frost on the ground evaporates. I have repeatedly been able to check this statement with my thermometer. Towards the South as far as the eye can see the whole plain is still white. It is entirely coated with a film of hoar-frost only a millimetres thick. At times when the sun burns down on it, tracts about 60 miles wide can evaporate and disappear in one day.

There is no liquid water to be seen anywhere. No rain ever falls here or anywhere else on the planet, not a particle of hail or a flake of snow. Hoar-frost is the only form of precipitation there is, everywhere, even in the tropics, and it settles as a thin coat in the night, if the atmosphere is not too dry, particularly during the long winter at and near the Poles, especially in the Southern hemisphere, where the winter is longer and colder….I have had the greatest difficulty in preparing sufficient drinking water for my own needs from the hoar-frost. I have often had to work for hours to replenish my reservoir with sufficient hoar-frost. And I had quite enough fuel to melt the ice! Is it any wonder that only a few plants, a few living creatures, can eke out a living here.1)                                  

Schiaparelli and Lowell ought to be able to have a look about here. Their tales about the canals here and hence the highly cultured inhabitants of this planet tempted me to pay this visit! I wish they were able to come here too, and see how even the very drop of water is lacking. If only they could come and see with their own eyes the variation between the bare heights and the lowlands covered with plants. They would never find their canals. There are no thick caps of snow and ice, the water of which when melted flows in tremendously wide canals, sometimes double ones, to the middle of the planet. There are not even ditches, or tracks. Yet there is some truth in their theories. It is the alternate evaporation of the two polar caps that makes the air moist enough for some months of the year to make it possible for plants to grow in lower latitudes. Their canals are through the air! And where, in places, in a long narrow valley, plants spring up, a dark strip is really formed!
But I recently saw myself how pardonable their error, their optical illusion, was. I was looking up at the Earth , at Europe, through my telescope. I saw one channel there, the English Channel. So that was alright. But as I gazed I found that it looked as though there were many more. All dark, scarcely visible spots in Europe seemed to be connected by thin black lines. Europe showed a network of canals that must each be many miles wide!

1)Does the writer here refer to animals? Certainly not to reasonable beings. From the fragments of his diary we get the impression that he was constantly alone there. But are these perhaps some smaller animals, insect-like creatures,  that live on the plants? We do not know! The parts of the diary that we have make no mention of the fact.
To be continued…

[R.M.Healey]

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