How strange is the Earth's interior?
Today I found this very interesting article.
http://www.livescience.com/strangenews/antimatter-particles-geoneutrinos-underground-100625.html
Exotic antimatter particles have been detected deep within the Earth’s interior, scientists report. Studying these particles, which are thought to result from radioactive decay within Earth, could help scientists better understand how the flow of heat inside our planet affects surface events like volcanoes and earthquakes. The particles, called geoneutrinos, are made of a strange type of matter called antimatter, which has properties opposite those of regular matter. When a regular particle, like an electron, meets with its antimatter partner, called a positron, the two annihilate each other in an energetic explosion.
Geoneutrinos are the antimatter partners of neutrinos, which are very lightweight, neutrally charged particles that are created within the sun and when a cosmic ray strikes a normal atom. An earlier project called KamLAND in Japan found the first signs of possible geoneutrinos in 2005. Researchers in the Borexino collaboration at the Gran Sasso National Laboratory of the Italian Institute of Nuclear Physics discovered the geoneutrinos inside a nylon sphere detector containing 1,000 tons of a hydrocarbon liquid. This sphere is encased within a larger stainless steel sphere in which an array of ultrasensitive photodetectors point at the inner nylon globe. Both of these layers are enclosed within a third 45-foot (13.7-m) diameter steel sphere holding 2,400 tons of highly purified water.
The whole experiment is buried nearly a mile (1.6 km) below the surface of the Gran Sasso mountain in Italy. All of these fortifications serve to shield the experiment from detecting anything other than neutrinos and geoneutrinos. These particles are incredibly difficult to find, because they pass through almost everything without interacting in any way. Over a whole year of searching for the elusive geoneutrinos, the experiment detected only a few signals. The detection of solar neutrinos, which produces a different pattern, is somewhat more common.
Any thoughts?
Can we expect more surprises when studying the interior of Earth?
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8 Answers
Wow…that’s fascinating!!! I’m wondering what kind of implications this has for the possibilities of other dimensions of space…I mean…as I understand it physicalists tend to claim that all there is is matter (or have I got it wrong…with the ascent of metaphysics???) so could this be a link to the spiritual dimension? :-/
Well, the existence of antimatter has been known for quite some time. CERN was even able to create anti-hydrogen atoms.
ß+ and ß- decay are well known as well
http://en.wikipedia.org/wiki/Beta_decay#.CE.B2.E2.88.92_decay
but the interesting part is actually detecting anti-neutrinos.
A more spiritual question could be why the atoms inside you and me have not been annihilated by antimatter. This is interesting too
http://physics.about.com/b/2010/05/19/fermilab-and-anti-matter-asymmetry.htm
The only way for physicists to really understand asymmetry is if particles and anti-particles behave slightly differently. One observed example of this is something known as the violation of CP symmetry (or CP violation).
One experiment shows that particles called neutral B-mesons, which oscillate rapidly between matter and anti-matter states in a sort of particle physics equivalent of multiple personality disorder, go from anti-matter to matter more rapidly than matter to anti-matter.
You should never expect surprises. ;)
Here’s another account from PhysicsWorld.com:
“The KamLAND experiment in Japan has detected neutrinos produced by radioactive decays deep inside the Earth for the first time. The experiment, which is located in a mine 1000 metres below ground, has detected electron antineutrinos from the beta-decay of uranium-238 and thorium-232, and placed an upper limit on the heat generated by these processes. If the accuracy of the measurements can be improved it may be possible to use ‘geoneutrinos’ to probe the Earth’s interior (Nature 436 499).”
”…The heat generated by uranium and thorium decay is the driving force for mantle convection, and hence plate tectonics and earthquakes. This result and future measurements using the same technique will provide useful inputs to Earth convection models.”
@mattbrowne , I used to read LiveScience.com but found it wasn’t always reliable. Take a look at ScienceDaily.com, one of many great science news sites.
Using Google I found a more technical description at Stanford.edu which says:
”As these radioactive isotopes beta-decay, they produce antineutrinos. So, measuring these antineutrinos may serve as a crosscheck of the radiogenic heat production-rate.”
I suppose you’d have to be a geophysicist to truly understand the significance of the research.
By the way, when they say that neutrinos are weakly interacting, that’s a real understatement. Typical neutrino can pass through a barrier of solid lead several light-years thick without interacting with any ordinary particles. Trillions of neutrinos are said to be passing through our bodies at every moment.
@Fyrius – Well, quantum mechanics was a surprise in 1900. So was special relativity in 1905, wasn’t it?
@mattbrowne
There’s no doubt that surprising things sometimes occur. But things are only surprising if you didn’t expect them. Thus to expect something surprising is a strange kind of paradox.
Better just to expect what would make sense, and be surprised if reality defies your predictions.
I’m sorry, I don’t mean to derail your thread. I’ll shut up and leave the last word to you.
@Fyrius – I always value your views. Well, I think suspense and anticipation is the fuel of researchers’ brains. It’s how the human mind works. Children enjoy surprises and adults stay young mentally, if they do too. Being able to enjoy surprises protects us from burning out.
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