Spectacular force: A georeactor deep in the ancient Earth's D''-layer (dark orange layer near core) goes supercritical - suddenly increasing temperatures to 13,000ºC. This turns rock into vapour, creating a rising bubble which pushes mantle, crust and atmosphere into space in a giant eruption.
Credit: Theo Barten
IT HAPPENED 4.5 BILLION YEARS AGO, when the Earth was barely 50 million years old. Life didn't exist; the planet was a violent, boiling fireball.
Then, without warning, the unimaginable happened. Deep within the core, a tremor started. The young Earth shuddered and erupted. From its bowels spewed a trillion-tonne column of molten and vaporised rock. On this day the Moon was born.
In his renovated Saxon farmhouse in Peize in the north of the Netherlands, retired nuclear geophysicist Rob de Meijer vividly paints a picture of the cataclysm: "The material in the Earth's mantle heated up some 8,000ºC and was completely vaporised.
This huge bubble of gas forced itself up through the still liquid mantle," he says. "As a result, part of the Earth's mantle and crust were blown away, as well as the early atmosphere. From the debris, the Moon could have formed rather quickly."
The Earth ejecting the Moon: isn't that a rather fanciful scenario? Not according to de Meijer and his colleague, petrologist Wim van Westrenen from the Free University in Amsterdam. They argue that this hypothesis is the logical consequence of new data, and also that an erupting Earth solves a number of unsolved and profound astronomical mysteries.
Weighing in heavily against the theory, though, is the fact that over the last few decades, scientists have reached consensus on a very different hypothesis for the origin of our Moon. According to that scenario, the young Earth was hit some 4.5 billion years ago by a primordial celestial body the size of Mars.
That impact would have been 100 million times as powerful as the meteorite impact that ended the age of dinosaurs 65 million years ago. The heat of such an impact would have vaporised a large part of the Earth's crust and mantle. Under this scenario, the impacting behemoth burrowed deep into the Earth, only to bounce back again.
Yet escape was out of the question. The core of the celestial body, rich in iron, was swallowed by the much heavier Earth and sank to its centre. The remainder was flung out to space, together with vast quantities of terrestrial debris, where it ended up in orbit around the Earth. In less than 100 years, this debris then accreted into our Moon.
Today, most scientists agree this 'impact hypothesis' is the most likely chain of events. The case was considered more or less closed in 2003 after geophysicists presented computer simulations which showed that a Mars-sized impactor could indeed deliver a Moon with the correct size and orbit.
But with their outlandish new hypothesis, de Meijer and van Westrenen are rocking the boat all over again.
One factor not considered by this theory?
The impactor theories have, if I understand correctly, the advantage of explaining how come so much of the Earth-Moon system's angular momentum is accounted for by the Moon's motion. It's hard to see how any genesis from within the Earth (which would of necessity conserve angular momentum) could match this constraint, and there is no mention of angular momentum considerations in the article, so can we assume that the theory has not yet been tested against these limits? It certainly ought to be an early line of enquiry in testing this theory for consistency with the observable facts.
Re: angular momentum
An ejection occuring from within a rapidly rotating fluid body might account for angular momentum.
Angular momentum considerations
In the scientific paper that we have submitted angular momentum is extensively discussed. It is noted that the angular momentum of the present Earth-Moon system does not differ much per unit of mass from e.g. Jupiter. There is no clear understanding of the detail processes in the formation of the planets in our solar system, so it is hard to state whether angular momenta are exceptionally high. Classical mechanics tells us that without external torques angular momentum is conserved. In our hypotheses there are no external torques and consequently the proto-Earth (before the "blow-out" of the Moon) rotated in about 2.3 hours in order to have the same angular momentum as the present system.
Rob de Meijer.
Could Mercury have blown out of Venus?
Hi Rob
I've corresponded with you before and it sounds like your work has progressed since then. Any further idea whether Mercury might have erupted out of Venus? Venus seems to be enriched somewhat relative to Earth in actinides, so perhaps a Bigger Bang could have resulted in a heftier object.
Adam Crowl
Could Mercury have blown out of Venus?
Dear Adam,
Yes the work is progressing but at present in a too early state to go into much detail. One of the properties that our hypothesis leads to (and is consistent with observations) is that the Moon has a very small iron core, since it mainly contains material of the Earth's mantle. If the process of a runaway nuclear reactor would have taken place at Venus and would have started from the core-mantle boundary of Venus, its moon would likely have a very small iron core as well. Mercury has, relatively speaking, the largest iron core of the inner planets. It would therefore be a surprise to me if Mercury would have been blown out of Venus by a runaway natural nuclear reactor in its core-mantel boundary.
Rob de Meijer
Venera 8 data
Hi Rob
My enhanced actinide data point was from Venera 8, but the later Veneras and Vega probes found comparable levels of actinides to Earth. Seems I'm 30 years behind.
How embarassing! I'll have to amend my blog accordingly.
Adam
moon origin
So first we had the Spinoff Theory, the Twin Theory and the Pickup Theory...when those didn't work so well, we added the Knockoff Theory...and now somebody comes up with the Blowout Theory. All right, now, suppose the internal reactor had been almost critical but not quite, and *then* there was a big impact from outside and the seismic waves compressed the material or something just enough to put it over the top...Wham - Kablooey! The Hey-that-was-neat-do-that-again Theory! You read it here first! But seriously, I think it's going to be a while before we know enough about just what goes on inside the Earth to prove or disprove the blowout theory, and it's likely going to be a while before we know enough to fix any problems there might be with the knockoff theory. I guess we just wait and see...
Questions about the Moons angular momentum? Composition? Origin?
...These and many other puzzles are resolved within the latest - Dec 2008 - (and complementary) Impact And Exit Event hypothesis. Take a look here: www.theimpactandexitevent.com
birth of moon
I am not trying to promote myself but I can show how all planets and moons are created at the center of the galaxy.
youtube.com/user/cobu2002 'plasma universe-new galaxies'
cosmicbubbles.webs.com
Fred Gangstad