You know how cop cars pile into each other in old comedy movies? That's how the Moon was built, say boffins The birth of the Earth’s Moon didn’t begin with a single huge collision – rather it grew as lots of baby moons from smaller impacts fused together, according to a new theory published in Nature Geoscience. Scientists believe that a proto-Earth and a Mars-sized body smashed together in the earlier days of the Solar System to …
"Perhaps Theia was also made from Earth-like material?"
The current thinking on the Giant-impact hypothesis seems to be that it resulted in thorough mixing of both parent bodies. If this is the case then both the Earth & Moon are comprised of the same mixture Proto-Earth & Theia. In other words, Earth-like material wasn't Earth-like material until the collision and mixing.
That's easy and happens currently with the Moon.
The Moon transforms the plastic Earth into an ellipsoid (mostly visible through tides).
The Earth rotates faster than the Moon orbits around Earth.
The ellipsoid bulge is thus always "ahead" of the Moon.
This slows the angular momentum (rotation) of the Earth.
Conversely, this increases the angular momentum (orbit speed) of the Moon.
A faster Moon moves out.
Continue until Moon orbit corresponds to Earth rotation.
Continue until Moon orbit corresponds to Earth rotation.
Which is estimated to happen in about fifty billion years time, IIRC.
It's only an estimate because the expanding sun will boil away the earth's oceans long before then, affecting the tidal dynamics between the earth and the moon. And when the sun does expand to consume the inner planets in about 4 billions years' time, the increase in friction will in any case cause the earth and moon to spiral into the heart of the sun and die in fiery dissolution.
45 years ago I was fond of the theories of Immanuel Velikovsky, because he was vilified by the establishment. Partly. He also had some interesting insights, such as catastrophism. We mostly agree now that dinosaurs died out after a rock less than 15 km in diameter narrowly missed the Mayan Riviera, some 66 million years ago. I think that if Velikovsky had grokked that a mere 10-15 km rock could do such damage, he wouldn't have bothered with the planetary wanderer theories that he did come up with. In short, I don't think that Velikovsky (died 1979) can help us resolve the controversy over how the moon might have formed.
There's a great viral (25 million+ views) video from a month ago of Montreal traffic helplessly colliding in what would normally be considered a minor snow-and-ice event. It has a balletic effect, soothing if one is not laughing too hard. That might be more like the new moon-formation theory. Not to say anything against the ballistic effect of the cop car pile-ons.
> because he was vilified by the establishment
Generally an indicator of Good Stuff in PC-infected 21st century politics and court economics.
In science, the "crank alerts" have to go on if mass appeal paperbacks and "imma being suppressed" books are hitting the airport shelves before peer-reviewed papers show up in the journals.
OTOH, the "mainstream" itself may be crank and in need of attitude readjustment as is the case with the current "multiverse" retardation bandwagon whereby meangingless drivel hidden underneath integral signs just doesn't stop. It must be the management equivalent of "avoid the hard work while still moving up" via memo control, fawning peacock meetings and fad pursuits.
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