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Caltech Researchers Weigh Individual Molecules
karvind writes "PhysOrg reports that physicists at the California Institute of Technology have created the first nanodevices capable of weighing individual biological molecules. This technology may lead to new forms of molecular identification that are cheaper and faster than existing methods, as well as revolutionary new instruments for proteomics. The Caltech devices are 'nanoelectromechanical resonators' -- essentially tiny tuning forks about a micron in length and a hundred or so nanometers wide that have a very specific frequency at which they vibrate when excited. Slashdot covered earlier the effort by Cornell for measuring attogram objects which also employs NEMS cantilevers."
You're right that the bonds make the total mass smaller. But we're talking about stable molecules here, which bonded in one specific way. If their mass were to change, they would have to decay or interact with the environment. If the molecule is stable, it's energy is very well defined. The only limiting factor is the principle of uncertainty, which basically tells here, that the longer you measure the mass, the more precise you are. So the deviation of the measurement may change, but not its expectation value. It would be very interesting, however, if we could apply this -- or other -- technique to measuring masses of unstable molecules and watch how it changes in time.
"Long run is a misleading guide to current affairs. In the long run we are all dead." (John Maynard Keynes)
We know the masses of a lot of the atoms (though there's a lot more than 1000 isotopes). Molecules are a completely different matter; there's an infinite range of possible molecules, because you can put them together in a lot of different ways; chain molecules (like DNA (hey, there's 5 billion different molecules - and that's only counting humans!)) are difficult to untangle and sort out; when you can weigh them, you can use the masses of atoms to try to calculate how many of each atom is in the molecule, and from there you can try and work out which configurations of atoms are possible.
Browsing with +2 to insightful posts and a higher threshold makes the average post seen seem a lot more ingenious
I'm familiar with his research, half my group collaborated with him, and I think I met him once. It's real. MEMS-based cantilever technology has been getting progressively better, this isn't particularly surprising.
I don't know why you're surprised that New Scientist is pseudoscience, but you can find similar results with real science in journals. Look up Roukes, M in "web of science" or something.
Nice troll, but I can't have you confusing the n00bs on matters scientific.