Justin Shofler posted this image http://www.msss.com/mars_images/moc/2005/09/30/2005.09.30.S0800321.gif
on the other forum http://www.markcarey.com/mars/discuss-29672-plumes-from-venting.html
So what do you think? Are they deposits left by plumes or streaks caused by landslides?
--- This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcrops of south polar layered terrain. Their appearance in this July 2005 springtime image is enhanced by bright patches of carbon dioxide frost. The frost is left over from the previous southern winter season; by summer, the frost would be gone. ---
http://www.msss.com/mars_images/moc/2005/09/30/
What confuses me is that it says Illumination, Upper Left.
MOC imagery is almost always illuminated from the left - as the local time is about 2pm when MGS goes overhead and thus, with north at the top - the sun is to the left - granted, that goes out the window when you're right down by the poles - but still, it SAYS upper left...
However - it really does look like something tall, illuminated from lower right.
Doug
This one is from the same region (203.51°W, 84.55°S) in 10-2003 with a bit higher resolution. No plumes. Don't think that it settles anything though as it's from a different time in the Martian year.
http://www.msss.com/moc_gallery/r10_r15/images/R10/R1004526.html
And this (203.61°W, 84.77°S):
http://www.msss.com/moc_gallery/r10_r15/images/R12/R1203465.html
Hmmm. This one actually overlaps the image. Don't see any plumes, but I don't see any obvious rock formations that could be casting the shadows either.
http://www.msss.com/moc_gallery/r10_r15/images/R13/R1304106.html
Excuse the triple post, but I've compared the negatives of the relevant portions of the images in the below attachment. Really looks like wind streaks to me.
interesting comparizon babakam.
We note that the "stakes" do not appear on the other photo: no trace of anything higher, or of its shadow.
But the wind streaks too do not appear. so they may be not permanent, or recent, or seasonal.
Very interesting. What could make dark streaks able to appear or disappear into some months or years? This implies the existence of a dark chemical, or a chemicals which decomposes into carbon. Methane?
A possible explanation would be a process of concentrating dust in some points when the ice sublimates ( a process common on Earth when dirty snow sublimates). But when everything is dry and cold, the wind could blow these dust pockets. The next seasonal cycle makes these dust streaks concentrate again into small pockets, and this become "invisible" from far. Such a cycle would explain many strange features in the polar ice caps: dark spots appearing with season, dendritic structures, etc.
The dust would be that ordinary martian dust, which would appear black on these photos where exposition was set short, in order to show features on the very clear ice.
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)