Harry Costas, interesting question. The present-day science model answer is the giant impact with Theia and a proto-earth. After the giant impact between Theia and the proto-earth, the Moon continues to evolve from the debris disc postulated to form close to the proto-earth and the smaller, proto-earth continues to accrete and grow into its present-day size and mass.How did our moon form?
Smooth on near side
Rough mountains on the dark side.
Good observation. Harry Costas did ask, 'How did our moon form?'The reason the Moon is so rough on the far side is because the far side is exposed to incoming impactors. Anything aimed at ther near side of the Moon has to get past the Earth first.
Helio, I have many reports in my home database using MS ACCESS that show various reports on the giant impact scenario for the origin of the Moon - too many nowThe Moon has some unusual features that has led to the idea that the Moon was originally formed, after the impact event, from two blobs. The book, "The Earth had Two Moons", is an interesting read.
Helio, the recent thread is here, Why is Earth's day 24 hours long (and how did the sun keep it from being longer)?, https://forums.space.com/threads/wh...-keep-it-from-being-longer.62225/#post-584950Although George Darwin was wrong with his spin-off hypothesis, what made him famous was correctly applying tidal friction to the orbital migration of the Moon due to tides.
I doubt there is anything that could tell us what the rotation rate of the Earth was prior to impact since all evidence, I assume, would have been destroyed by that cataclysmic event. Thus, we have to do retrodictive science where time is run backwards in the various models. BBT, of course, is another big example of running backwards in time to see what we might discover.
Only the models, however, that demonstrate a Moon forming are the ones that make any sense, so this seems to limit the sizes and impact angles Theia would have had.
I think there is a recent thread, and paper, that addresses how little the Moon has migrated in the past 2 billion years, which surprised me. But I didn't dive into it, yet it might be worth reviewing.
Yep. Theia messed things up in that regard.Concerning Earth's original LOD, the problem is finding the rocks and strata to document that
Harry Costas, what makes your post here different than what I presented about the origin of the Moon in my post #8? "I have a 1963 book, The How and Why Wonder Book of the Moon. Pages 4-6 discuss the origin of the Moon,"If everybody walks the same path, they will trip over the same path.
No theory has solid foundations.
Thinking outside the circle, or off the beaten track.
Imagine a few billion years ago.
The possibility, that our Sun gained enough matter travelling through a Nebulae.
Had enough Dipolar Electromagnetic Vector fields expelling matter in the form of an hourglass, the Iron and heavy metals formed planets and moons and millions of rocks.
Water expelled to the outer solar regions.
In Chaos for millions if not billions of years.
If the Earth and the Moon were formed at the same time from such origin.
This can explain their unison motion.
We can explain the properties of the Moon near face and the dark side by gravitational impact by Earth and the Sun.
If they were both molten at the time.
The properties can be explained by physics.
Yes, the moon and Earth have had many impacts, some deep.
The mountains on the dark side are amazing.
The Russian were the first to observe the Dark side back in 1959.
Nucleosynthetic isotope anomalies in meteorites allow distinguishing between the non-carbonaceous (NC) and carbonaceous (CC) meteorite reservoirs and show that correlated isotope anomalies exist in both reservoirs. It is debated, however, whether these anomalies reflect thermal processing of presolar dust in the disk or are primordial heterogeneities inherited from the Solar System's parental molecular cloud. Here, using new high-precision 84Sr isotope data, we show that NC meteorites, Mars, and the Earth and Moon are characterized by the same 84Sr isotopic composition. This 84Sr homogeneity of the inner Solar System contrasts with the well-resolved and correlated isotope anomalies among NC meteorites observed for other elements, and most likely reflects correlated s- and (r-, p-)-process heterogeneities leading to 84Sr excess and deficits of similar magnitude which cancel each other. For the same reason there is no clearly resolved 84Sr difference between NC and CC meteorites, because in some carbonaceous chondrites the characteristic 84Sr excess of the CC reservoir is counterbalanced by an 84Sr deficit resulting from s-process variations. Nevertheless, most carbonaceous chondrites exhibit 84Sr excesses, which reflect admixture of refractory inclusions and more pronounced s-process heterogeneities in these samples. Together, the correlated variations of s-, (r-, p-)-process nuclides revealed by the 84Sr data of this study refute an origin of these isotope anomalies solely by processing of presolar dust grains, but points to primordial mixing of isotopically distinct dust reservoirs as the dominant process producing the isotopic heterogeneity of the Solar System.