Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: sci.space Subject: Re: Sorry Henry, There **is** proof on Martian surface chemical composition. Message-ID: <7276@utzoo.UUCP> Date: Mon, 3-Nov-86 15:24:07 EST Article-I.D.: utzoo.7276 Posted: Mon Nov 3 15:24:07 1986 Date-Received: Mon, 3-Nov-86 15:24:07 EST References: <8610310817.AA15131@s1-b.arpa> Organization: U of Toronto Zoology Lines: 59 > In Vol. 7, Nr. 29 of Space Digest, Henry Spencer claimed that the > existence of **all** the elements on Mars necessary for life and the > industrial development of Mars is unproven... I don't have archives that go that far back, but as I recall, my skepticism was directed at the presence of things like ore bodies, not at the existence of some of the more common elements. > [Viking lander data] The Vikings gave us data on the first few centimeters of surface in two small areas. The close agreement between the two is heartening, but it's still awfully thin evidence to base industrialization on. In particular, we have no idea whether that is the bulk composition or just that of the surface; this matters quite a bit. Topsoil is not really representative of the bulk composition of the Earth's crust. > All of the elements necessary to support life exist on Mars. However > based on this evidence, Mars does lack some elements necessary for > human health and those are: Iodine and Phosphorus... Based on this evidence, it lacks quite a few in fact. A surprising number of elements are needed for human health, albeit many of them only in trace quantities. The percentage of cobalt, for example, in the human body is minute... but no cobalt equals no vitamin B12 equals death from pernicious [?] anemia. Much more serious than trace elements or even relatively minor ones like phosphorus is the distinct shortage of hydrogen -- water is not a trace requirement! There is probably quite a bit of water in Martian permafrost, but we don't know that for sure. > The extreme richness in iron is particularly exciting... A fair bit of iron, yes, but I wouldn't call it "extreme richness", not when comparing it to things like nickel-iron asteroids. > So there you have it. Mars is a rich planet for industrialization. It may be about as good as any planet, apart from the shortage of water and the annoyingly thin atmosphere. It still has all the problems of planets as industrial bases in general: inescapable gravitational fields, atmosphere that is hard to exclude, a deep gravity well that (particularly in combination with the atmosphere) makes transportation expensive, daily and seasonal temperature cycles, unavailability of solar power during the night. Mars also has a couple of problems of its own: surface roughness and dust storms. Mars makes Earth look flat; its terrain is a major challenge to transportation systems, especially in active areas like the neighborhood of the polar caps -- an area otherwise very interesting because of probable ample supplies of water. And it has dust storms on a planetary scale, very long-lived and widespread. They are bad news for solar power -- those storms are pretty opaque, from the Viking data -- and I believe they also chill the surface pretty thoroughly. I also doubt that spacecraft would find landing or taking off in a dust storm particularly safe. Mars may be a rich planet, but it's got some real problems as an industrial base. "Is the surface of a planet the best place for an expanding industrial civilization?" -- Gerard O'Neill "No." -- ibid -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,decvax,pyramid}!utzoo!henry