From the Creation Evolution Headlines website:
Mercury is weird
David Rothery, planetary scientist at The Open University, remarks on The Conversation that “The more we learn about Mercury, the weirder it seems.” As we shall see, weirdness is not limited to Mercury.
For such a tiny planet, Mercury is a pretty big puzzle for researchers. NASA’s MESSENGER probe already has revealed that the planet is surprisingly rich in elements that easily evaporate from the surface, such as sulphur, chlorine, sodium and potassium. This is incredibly odd as these kind of substances most likely would disappear during a hot or violent birth – exactly the type of birth a planet so close to the sun, such as Mercury, would have had.
Scientists are also struggling to understand why Mercury is so dark and what its earliest planetary crust, created as the newly-formed planet cooled down, was made of. Research has now started to throw up answers – but these are raising a lot of new questions.
Perhaps their research is starting to “throw up answers” because all the proposed answers are making them nauseous. One thing is clear from this quote: the puzzles come from dating the planet as billions of years old. Elements that easily evaporate should not be there after that long. A BBC News article sounds more confident, explaining that the unexpected graphite found on the surface may have floated on top of Mercury’s original molten interior. It doesn’t however, address the puzzle of surface volatiles that should have disappeared during a hot or violent birth.
There are a lot of weird planets out there.