Mercury has a magnetic field, which quite surprised planetary scientists when it was first discovered by MAriner 10, as the prevailing theory at the time was that Mercury's small size would have led to its core solidifying by now and stopping the dynamo that generated the field.

There's obviously a lot we don't know about planetary magentic fields, and I wouldn't want to judge the entire theory just by something I read on Slashdot, but I find it hard to understand how oceanic currents could account for Earth's magnetic field but not for Mercury's.

Oh, those scientists are still unable to do what cro-magnon man could: make a simple obsidian rock pointy like an arrowhead.

Um, what? Obsidian knapping is practiced by many people around the world who are quite capable of producing fine points. You can find howtos on YouTube, so it's far from being a lost secret of the ancients.

Best to check those overly broad claims before committing yourself to perpetuating them.