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Creating Designer Isotopes
Roland Piquepaille writes "According to a Michigan State University (MSU) news release, 'Made-to-order isotopes hold promise on science's frontier,' nuclear physicists can now start a new career as isotope designers. These scientists can build specific rare isotopes to solve scientific problems and open doors to new technologies. The lead researcher says this approach has already given us the Positron Emission Tomography (PET) scan technology. He's now going further, saying that he wants to build objects 100,000 times smaller than the atomic nucleus. He calls this 'femtotechnology.' Also available are additional details and pictures of the tools used for this kind of research, picked from a 415-page design paper." Update: 05/11 14:30 GMT by SS: Readers have noted that the summary inaccurately portrays the scale of the 'femtotechnology.' The MSU researcher refers to "the capacity to construct objects on an even more minute scale, that of the atomic nucleus 100,000 times smaller."
The chemical changes that brought about the formation of the elements in the bellies of stars...
If you're changing elements from one to another, it's not a chemical change. It's nuclear! That's one of the definitions of a nuclear change. What kind of science journalism is this?
You cannot build structures with electrons and positrons which are this small. The reason being that the binding energy for EM processes (the strongest force which an e+/- feels) is far too weak to confine the particles to a region as small as 1 fm. For example positronium has a binding energy of 6.8eV, roughly half that of a hydrogen atom and hence it will be slighly larger.
The misconception comes about because the electron is not a particle but a wave. You can trap the wave in a potential but it is still a wave. The smaller the space you want to confine it to the shorter the wavelength required and as the wavelength decreases the energy increases (deBroglie wavelength lambda=Planck's constant/momentum [lambda=h/p]). This means that energies O(10^6) times larger than EM binding energies to confine an electron to such a small area.
The only force we know of that is strong enough to do this is the strong nuclear force which is only felt by quarks. Hence, given our current knowledge, the only thing you could build such a tiny structure out of is quarks...which is why the nucleus is made of these!