'not expressly forbidden'

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There is a saying in astronomy/physics which goes something like... 'anything not expressly forbidden is compulsory' which is about the same as saying '**** happens'.  

It comes into play in situations like forbidden emission/absorption lines in spectroscopic analysis...  astronomers will see these lines in spectra, although they are technically forbidden.  

What is meant by 'forbidden' in this case is that the transition which would cause the spectral line is extremely unlikely via quantum mechanics. As in once in a billion, billion times. And if there is any other way the transition  could occur, it will almost always happen in that way.

However, forbidden lines do happen because, while the chance of them is very, very small and the likelihood of a any  other way of that transition happening in very, very high, in interstellar gas clouds there are a large, large number of atoms which are at very, very low densities.  We're talking about better than the best vacuum created on the Earth.  So there is almost no interaction between the atoms in the gas cloud, which means there is almost no other way for the transitions to happen.  So you get forbidden spectral lines.

So what does this have to do with PSU or IT?

If a student or employee at PSU can log into a web application with their PSU Access Account and change any of their identifying information (name, PSU ID#, user name. etc.) accidentally or on purpose during the process, someone, at some point, will do so.  Even if it makes no sense to do so.  

It is inevitable unless completely and totally prevented by the developer in all cases, at all times.

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This page contains a single entry by ERIC AITALA published on August 22, 2008 3:09 PM.

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