Mars isn't supposed to have enough convection in its mantle to create a magnetosphere. As you mention you need an atmosphere and a magnetosphere to create an ionosphere, where the plasma caused by upper atmospheric elements ionized by the Solar wind is held in place by magnetic field lines. I fink.

It just goes to show, every time they think they know something about the Red Planet, they find out something new that forces them to reappraise. Although, given that the exact mechanism for the generation of our own magnetosphere is still uncertain, it shouldn't really be surprising?

Certainly worthy of entertainment.

Most of these pictures of "trees" are so obviously not trees simply by looking at the dark portions that extend away from the apparent objects. They clearly are not shadows, as they often extend in a direction not in line with definite shadows. The conclusion therefore is that they are physically related to the structures in question. If these structures are gaseous in nature, well there you go.

Originally posted by blue bird
But - look carefully at this image - jets!? ...don't think so:

I don't think so either, but the fact that they are near small jets made me think they are also CO2 releases but not as a jet, maybe because they are near the surface the CO2 is just released on that area.

Having said that, does anyone know what could be the reason for that dark colour? Can the CO2 react with something on the surface?


PS: images that large mess all the page, post only a link when you want to show images larger than the "normal".

Those comparisons between the Amazon forest and Mars mean nothing without scale.

Are we looking at photos with the same resolution? Is the photo from Mars closer than the photos from the Amazon forest or is it the other way?

Originally posted by ArMaP


Having said that, does anyone know what could be the reason for that dark colour? Can the CO2 react with something on the surface?

*rocks springing out , they say - mixed with dust....

But, there is article in Nature saying that these spots bear VERY WEAK signature of CO2.

But the authors of a second study in the same issue of Nature question whether the conditions for forming such jets exist in the areas where the spots are seen. Yves Langevin of the Institut d'Astrophysique Spatiale in Orsay, France, and his colleagues base their argument on observations by the European Space Agency's Mars Express spacecraft.

They point out that the areas where the spots appear are "characterised by very weak signatures of CO2 ice, which are not consistent with a thick transparent slab of CO2 ice". This means that whatever CO2 ice is present must be buried beneath the surface, making the jets hard to produce, they say.

Christensen says this is entirely consistent with his team's model. The Mars Express observations were made in the Martian southern hemisphere's late spring, by which time the jets would already have been active for about 30 days, he says. The jet activity would have coated the surface of the ice with lots of sand and dust, leading to the weak CO2 ice signal.

Langevin and his colleagues also question why the spots and spiders do not appear in other places in the south polar cap where Mars Express clearly detects CO2 ice.

Christensen says the jets require a combination of things to form, including clear, dense ice and underlying sand. “I can imagine that the conditions wouldn't always be just right for them to form,” he counters.

Originally posted by blue bird
ArMaP * scroll all the way down:

I know that photograph, what I wanted to say is that I have not seen any photo with better resolution, like those from HiRISE, of an area with those "spider" formations.