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
According to the latest scientific insights, we get to a factor of 20 below the 250 ppm that is needed. "We're hardly worried about the remaining factor of 20, considering all the uncertainties when dealing with the inside of the Earth," says van Westrenen. "The D''-layer is not homogeneous…there will be hotspots where the concentration of uranium and thorium is much higher."
De Meijer adds: "We're also reassured by the fact that you need only five per cent of all uranium and thorium in the D''-layer to launch the Moon. That is not outrageously much."
The idea is also supported by geologist Alex Corgne at Macquarie University in Sydney, an expert on the subject of the mineralogy of the D''-layer who says, "The conclusions by de Meijer and van Westrenen are completely credible."
So it's likely that all ingredients for a georeactor were present within the young Earth. What remains, though, is how to get it started.
Like J. Marvin Herndon's georeactor in the core, georeactors in the D''-layer must be fast breeders: nuclear reactors designed to 'breed' fuel by producing more fissile material than they consume.
In this type of reactor, the neutrons generated by the spontaneous fission of uranium-235 are used to transform uranium-238 and thorium-232 into new fissile material - uranium becomes plutonium-239, thorium becomes uranium-233.
There was certainly no shortage of suitable isotopes. In the early days of the Earth, no less than 25 per cent of all uranium was fissile uranium-235; today, after 4.5 billion years of decay, only 0.7 per cent remains. Man-made nuclear reactors generally use enriched uranium, in which the uranium-235 content has been increased to four per cent. But the young Earth contained a potent mix.
Considering this, according to de Meijer, it was simply a case of getting overheated rather than exploding. The mantle was already hot – about 5,000ºC – and the georeactor that went supercritical generated so much heat that it increased by an additional 8,000ºC.
"All rock vaporised. It literally created a large bubble of gas in a fluid soup. When you put a pan of soup on the fire, you also get bubbles of vapour that shoot up," he says.
It was Archimedes's law at work. The difference in density propelled the bubble of vapour upwards, taking everything in its path with it, including parts of the mantle and crust. Even the primordial atmosphere must have been sucked away from the Earth by the erupting matter.
What happened after that is speculation. "Presumably, a ring of debris formed around the Earth, out of which the Moon then gradually coagulated," guesses van Westrenen.
This raises the question: could something similar happen today? Researchers don't think so; the Moon drew so much energy from the Earth in that blast that too little is left for an encore. However, de Meijer believes that the georeactors in the D''-layer remain active.
"There could still be places where fissile isotopes reach the critical concentration for forming a georeactor. Remember that georeactors are fast breeders that produce more fuel than they use," he says.
He also knows how to find out. Both natural decay of uranium and thorium produce antineutrinos, tiny particles that can fly straight through the Earth and you and me. Considering the inaccessibility of the D''-layer, an antineutrino detector is the only way known to prove the existence of a georeactor. But such a detector must be able to detect the energy and direction of the antineutrinos, because artificial nuclear reactors produce them, too.
De Meijer has been working on precisely this type of direction - sensitive detector. "We made a design that looks feasible. The next step is building a prototype. We hope to start soon."
Marcel Crok is a science journalist with Natuurwetenschap & Techniek magazine in The Netherlands.
Birth of the Moon: a runaway nuclear reaction?
I read a rather instersting article about how writers approach stories regarding new scientific theories. And reading this article it struck me just how true there was in that article.
Once again, the guy with the new theory, in this case Rob de Meijer and his coleague, is being painted as mavericks. He is trying to attain legitimate consideration for his "radical" new theory. He has an uphill battle against the well established theories of his peers and they will do everything they can to debunk him and his ridiculous theory.
Well for one thing, why don't you let your readers decide for themselves whether a theory is outlandish.
Also, debunking theories, new or old is how science works. Theories are supposed to be able to stand up to scrutiny. Eventually, the evidence will either lend credence to or disprove the theory.
Not A 'Maverick' story in my world
From my read of the article, we have a scientist who has an interesting new idea about the moons formation that, if it proves to be viable, might explain some anomalies in the system, relative to the other popular explanations.
I don't see any "people are trying to suppress me" whining. I just see someone with a fledgling theory that seems properly (dis)provable and he's trying to put together an experiment that would properly put his theory to a test.
If he manages to build his anti-neutrino detector, I'd like to see what results it generates. Among other things, I'm curious about it detecting antineutrinos that are unrelated to either georeactors or human-built reactors -- and what that might expose about the universe around us.
THE MOON
IT SEEMS TO ME THAT THE MOON WAS CREATED IN A COLLISION. IT MAY NOT BE TRUTH. THE MOON WAS CREATED AT THE SAME TIME AS THE EARTH. IT NEED TO BE SUPER HOT TO FORM THE CIRCLE. IS LIKE A DROP OF WATER WHEN IT FALLS IT MAKES A PERFECT CIRCLE, BECAUSED OF THE GRAVITY. SO IF A COLLISION OCCURED THE MOON WOULD NOT BE IN A PERFECT SHAPE THAT IS NOW. IT WILL BE LIKE THE ASTEROIDS WITH NO FIGURE IN SHAPE. MAGMA ONCE IS COLD WILL DO DIFRENT SHAPES. BUT WHEN IS HOT AND CONTINUES TO BE HOT WILL FORM A PERFECT CIRCLE ONCE YOU DROP IT IN THE AIR. WILL FORM A PERFECT CIRCLE. AS THE MOON NEED TO SUPER HOT TO BE IN THE SHAPE THAT IS NOW.
Energy calculation
"....a one gigawatt nuclear reactor generates just 1017 joules a year.."
I guess this is probably meant to read "3 x 10^16 joules a year"
Calculations
Similarly " ...so you'd need the annual energy production of 1013 of these reactors to get the same amount."
I guess this should read "10^13".
Error in typography
On p5 of this article, surely the phrase "a one gigawatt nuclear reactor generates just 1017 joules a year," should read "a one gigawatt nuclear reactor generates just 10^17 joules a year,"
Errors fixed
Thank you, dear readers. Sometimes superscripting drops off in translations to the web, unless we keep out an eagle eye. All fixed now!
Wilson da Silva
Editor-in-Chief
page 5 (& printable) still broken.
page 5 (& printable) still broken.
The superscript tag isn't closed, so some text is missing and everything after it is in superscript.
You have (using the wrong brackets so they don't get exec'd):
[sup] 13[/su
where you need
[sup]13[/sup]
page 5 (& printable) still broken.
page 5 (& printable) still broken.
The superscript tag isn't closed, so some text is missing and everything after it is in superscript.
You have (using the wrong brackets so they don't get exec'd):
[sup] 13[/su
where you need
[sup]13[/sup]
I agree with the other visitor
Yes! Please fix your html so we don't need to view source to see the end of a sentence.
Also, and I ask so many media outlets to do this, put an e-mail address on your contact page specifically for typos, wrong information, etc, so we don't just post comments you're likely to not read often!