acscmad@sunybcs.UUCP (Michael Domino) (02/11/85)
----------------------------------------------------------------------- From the Associated Press: SAN FRANCISCO - Water on Mars vanished after carving the famed canals 3 billion years ago, and scientists say discovering where it went will help them find drinking water for earthlings who someday may colonize the Red Planet. "Obviously, one would not want to take water on a journey to Mars, but would want to look for a local source," said Arizona State University geologist Ronald Greely, who headed a meeting of scientists preparing for an unmanned mission to Mars in 1990. The most likely sources of water are vapor in Mars' thin atmosphere, ice in its huge polar caps--which are mostly frozen carbon dioxide-- and permafrost that may lie under its reddish soil. The canals are 2,000 to 3,000 miles long and 1,000 feet deep. ------------------------------------------------------------------------- Now the last I heard there were NO canals on Mars; that what seemed to be canals were only optical illusions caused by strings of craters, and that the truth was discovered with the advent of telescopes of adequate resolution. What's the truth, astronomers of the net? -- ------------------------------------------------------------------------------- Michael A. Domino uucp:[bbncca,decvax,dual,rocksanne,watmath]!sunybcs!acscmad SUNY/Buffalo Computer Science csnet:acscmad@buffalo arpanet:acscmad.buffalo@csnet-relay voice:(716)881-6420 -------------------------------------------------------------------------------
lindley@ut-ngp.UUCP (John L. Templer) (02/12/85)
> From the Associated Press: > > SAN FRANCISCO - Water on Mars vanished after carving the famed canals > 3 billion years ago, and scientists say . . . . . > ------------------------------------------------------------------------- > Now the last I heard there were NO canals on Mars; that what > seemed to be canals were only optical illusions caused by strings of > craters, and that the truth was discovered with the advent of > telescopes of adequate resolution. What's the truth, astronomers of > the net? > -- > ------------------------------------------------------------------------------- > Michael A. Domino uucp:[bbncca,decvax,dual,rocksanne,watmath]!sunybcs!acscmad > SUNY/Buffalo Computer Science csnet:acscmad@buffalo > arpanet:acscmad.buffalo@csnet-relay voice:(716)881-6420 > ------------------------------------------------------------------------------- The canals that Percival Lowell (sp?) and others thought they saw were indeed optical illusions. However, there are many features on Mars best explained by the past pressence of running water. These include "river tributary systems" and canyons. I believe that these are too small to see from Earth, especialy with the telescopes of Lowell's time. It sounds like the AP writer didn't understand the distinction. -- John L. Templer University of Texas at Austin {allegra,gatech,seismo!ut-sally,vortex}!ut-ngp!lindley "and they called it, yuppy love."
rivers@seismo.UUCP (Wilmer Rivers) (02/12/85)
> From the Associated Press: > > SAN FRANCISCO - Water on Mars vanished after carving the famed canals > 3 billion years ago, and scientists say discovering where it went will > help them find drinking water for earthlings who someday may colonize > the Red Planet. > > The canals are 2,000 to 3,000 miles long and 1,000 feet deep. Schiaparelli's (1877) canals, made famous by Percival Lowell, were about this long, but no depth can be attributed to them, since in fact they did not actually exist. As Michael Carr writes in "The Surface of Mars", "...the canals appear to be largely an imaginary perception on the part of the observer of irregular groups of surface markings close to the limit of telescopic resolution." The AP report appears to be confusing these non-existent "famed canals" with 2 other features which really do exist : the immense system of connected canyons (originally called the Coprates Canyon, now the Valles Marineris) just south of the Martian equator, and the much smaller networks of erosive channels, at least some of which once contained running water (however briefly - perhaps in a flood). The canyon system, which appears to have been formed by collapse rather than by running water, is a total of 4000 km long and is 7 km deep in places. The channels, on the other hand, show signs of flowing water (or ice, or in some cases lava), but they are only tens of km long, sometimes connecting to 300-km long networks, although certain fluvial features extend about 2000 km (these last are outflow features from catastrophic floods rather than remnants of long-lived drainage). The reporter seems to have been less than clear in the distinction.