Moon and the Earth Compared (59)

Introduction

The following is a very concise piece of text comparing the Moon and the Earth.

The following excerpt comes from the book “Moons of the Solar System (From Giant Ganymede to Dainty Dactyl)” by James A.Hall.

Excerpt

“Most other major moons orbit along the equator of their planet. Our moon does not; rather it follows a margin along either side of the ecliptic, of about 5°.

It is also almost perfectly round. The moon’s roundness exceeds that of every planet (or at least every superior planet. Mercury is also very round.) Visually, it looks unusually flat. Most planets from our viewpoint are brighter near their center than at their limbs. It is also important to note that many other moons appear equally fuzzy at the edge from their own planets. Luna is different. The full moon is evenly lit at all parts, which was noticed by, and puzzled, the ancient Greeks.

Continuing onward, Earth and the Moon spin in similar orientations. Moon samples indicate the surface of the Moon was once liquid rock, or magma. The Moon is believed to have a relatively small iron core (but comparable to the Earth’s core by percentage of total mass and volume, accounting for density). Its density is lower than Earth’s own, but only slightly. Stable mineral isotopes of lunar and terrestrial rock are identical, implying a common origin.

Finally, until 2015, our moon was considered unique in having an electromagnetic field of its own. Recently Hyperion was found to have one as well, but much weaker than our moon, which has the strongest electromagnetic field found around a moon. In March of 2015 Ganymede was found to also have its own magnetic field.”

Summary

The Moon is almost perfectly round, and it appears in the night sky equally bright all over its face.

It has been found that the Moon has an iron core and even has a magnetic field (very weak).

As mentioned above in the excerpt the Moon does not orbit the Earth in line with the Earth’s equator, but at a 5.19° angle, which can be seen in the diagram above. The reason for this is not known and is certainly a very strange point, as other moons do not do this, they rather orbit their planet in line with their planet’s equator.

End (59).