Space/Science — HabitableZone

Space/Science » in reply to re: To each his own

active geyser vs passive spot
nick hoffman — (archived)

The virtue of a geyser is that ejects a nice plume of dusty gas. Spots may be must less capable of generating dust, especially if it is good dark staining dust that must travel some distance to make the surface streak.

Thereis room for a fairly wide range of behaviour here, but my personal vote is that the coincidence of spiders and surface streaks tends to implicate an active geyser rather than a passive spot.

Another problem with the spot model is that we haven't established yet that the spots really are that dark - they are certainly paler than the clean ice, but with the limited available springtime light and the huge contrast in the image, they could still be quite a light grey or tan. More work is needed on spots and, indeed, on the defrosting behaviour of the ice in general.

I still maintain that there are active springtime flows of gas-lubricated dust and CO2 ice, and recent images have continued to accumulate evidence for tracks appearing in near-polar gullies at a critical moment in springtime.

e.g.

http://www.msss.com/mars_images/moc/2005/12/09/

http://www.msss.com/moc_gallery/s05_s10/full_jpg_non_map/S10/S1000462.jpg" Full Image Here

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