Origins of the Moon and Life on Earth

compiled by Lewis Loflin


See the graphic Science Vs. Environmentalism

The moon was formed from the earth. Why this is a good hypothesis:

The Earth has a large iron core, but the moon does not. This is because Earth's iron had already drained into the core by the time the giant impact happened. Therefore, the debris blown out of both Earth and the impactor (the size of Mars) came from their iron-depleted, rocky mantles. The iron core of the impactor melted on impact and merged with the iron core of Earth, according to computer models.

Earth has a mean density of 5.5 grams/cubic centimeter, but the moon has a density of only 3.3 g/cc. The reason is the same, that the moon lacks iron.

The moon has exactly the same oxygen isotope composition as the Earth, whereas Mars rocks and meteorites from other parts of the solar system have different oxygen isotope compositions. (An isotope varies in the number of neutrons in the nucleus.) This shows that the moon formed form material blasted from the earth.

If a theory about lunar origin calls for an evolutionary process, it has a hard time explaining why other planets do not have similar moons. (Only Pluto has a moon that is an appreciable fraction of its own size.) Our giant impact hypothesis had the advantage of invoking a stochastic catastrophic event that might happen only to one or two planets out of nine.

This was important in supplying enough iron in the core (a ball spinning in an ocean of molten iron/metal) that produces a magnetic field to shield the earth from solar wind generated by the sun. This was also responsible for the earth's axial tilt of 23 degrees and early fast rotation to allow water (forming massive tidal waves) to break down rocks to create primordial oceans saturated with dissolved minerals.

Life later began by unknown causes in those oceans. The formation of the moon in such a manner unknown in the rest of the solar system made life possible on earth.

History of the Earth by William K. Hartmann and Ron Miller P. 45-55


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