So Mars may still have a liquid iron core, eh? How can that be reconciled with the absence of an appreciable magnetic field? If the dynamo theory is correct, and Mars has a liquid iron core, shouldn't we see a substantial magnetic field today?

There is evidence of a strong ancient reversing field, but no sign of one now or in the recent past. So what is going on?

If the core is liquid then it is hot. That heat is going to escape. If the core is liquid, then the near surface interior is going to be a good deal warmer than previously believed. Liquid water may be much closer to the surface than some planetary scientists want to believe or accept. How would such a thing affect the evolution of the surface?

Traditional age dating formulas are showing considerable flaws on Mars. Many surfaces are seen to be quite fresh, but they are traditionally dated to the foggy mists of antiquity. How resurfacing and erosion works, and how so much of the planet seems to show differential erosion is a continuing mystery.

Is there snow on Mars? And does that snow persist through tens of thousands of years? Well, that seems to be the latest argument offered to explain the apparently fresh gullies on Mars. Snow falls periodically but rarely, and melt water flows beneath its protective cover. Apparently the argument is there has been no snow for 50,000 years (or whatever) even though gully-carving is going on right now -- or at least seems to be. How is snow that fell tens of thousands of years ago preserved on a surface that annually warms above freezing? Got some 'splaining to do.

And as for those dark streaks conventionally explained as 'dust avalanches': can some of them be explained by alternative mechanisms such as outbursts of water vapor or even liquid water? Several issues need to be studied in relation to the streaks: 1) Is there really a planet wide dust cover on sharp slopes that can be induced to avalanche? 2) How does the dust accumulate on such severe slopes in the first place? 3) Is the underlying surface as dark as the streaks? 4) If so, how is all dust removed to fully expose the underlying dark surface? 5) If the underlying surface is not so dark, what causes the darkness we see? 6) What about the light streaks found in some areas? Are they 'dust avalanches' too? If a dark surface on Mars is NOT dust covered, where does the dust come from to form the light-colored 'avalanches' -- if that's what they are?

There are of course many more issues to raise, but these are some that come to mind this fine Sunday morning.

Cheers, BFelix