Mercury the moon

Mercury

Mercury

Our Moon

Our Moon

The video above, from NASA, shows Mercury’s south polar region.  Mercury not only looks like our moon, but also shares more similarities with our moon than any of the planets in our Solar System, including:

  • Mercury has no atmosphere, neither does our moon.
  • Mercury is heavily scarred with craters and lava mares, like our moon.
  • Mercury and the moon are of similar size – less the half the size of the Earth.
  • Mercury is highly rich in iron (in fact the most iron-rich of all the planets by a large margin), as is our moon.

The video below is from the Science Chanel – it explains the closeness of Mercury and our moon.

Mercury is very dense. As Alan Stern says above: “Mercury [is] mostly a core and little else.” Mercury’s density cannot be explained by slow-and-gradual-development models. So the preferred scientific explanation is that billions of years ago, a large object crashed into Mercury, stripping away its lesser-dense material, leaving behind the high-density planet seen today. In other words – leaving behind the Core of the planet. This supports the book’s explanation of the “Sacred Path of Migration” which says that Mercury was once a planetary Core.

Diagram of the interior structure of Mercury. The metallic core comprises most of the planet’s interior. Credit: Nicolle Rager Fuller, National Science Foundation

Diagram of the interior structure of Mercury. The metallic core comprises most of the planet’s interior. Credit: Nicolle Rager Fuller, National Science Foundation

The moon once harbored a dynamic molten core

The moon once harbored a dynamic molten core

Another similarity between Mercury and our moon is that they both are unexpectedly magnetised! (Find out more about our magnetised moon here.) Quoting from the Astronomy Notes of astronomy professor Nick Strobel from Bakersfield College, California:

Mercury is a bit surprising because it has a weak magnetic field. Mercury is the smallest of the terrestrial planets, so its interior should have cooled off long ago. Also, Mercury spins slowly—once every 58.8 days. Mercury’s high density tells us that it has a proportionally large iron-nickel core. 

Mercury’s situation was a major challenge to the magnetic dynamo theory. In true scientific fashion, the theory made a testable prediction: Mercury should have no magnetic field or one even less than Mars’ one because its core should be solid. Observation, the final judge of scientific truth, contradicted the prediction. Should we have thrown out the magnetic dynamo theory then? Astronomers were reluctant to totally disregard the theory because of its success in explaining the situation on the other planets and the lack of any other plausible theory.

I’ve highlighted the last few words of the quote because the professor makes a valuable point – the current scientific explanation for how Mercury could be magnetised does not fit the data, but there is no other scientific explanation. The true nature of Mercury remains unknown.