

Originally posted by anoncoholic



Originally posted by TMJ1972



i would suggest, the more astronomic approach to checkout wether there are chemicals in the trail or not would be shooting a laser at it and draw a spectrum from the reflection, what about that ?







strange you would mention suing but not mention that pointing lasers at planes is illegal and hazardous

edit on 21-3-2013 by Aloysius the Gaul because: (no reason given)



Pointing a laser at a contrail is not the same as pointing it at a plane.not suer it woudl be much use though - since a laser is a specific wavelength of light all that can be reflected is that same wavelength - so your only possible result is binary - it reflects, or it does not.How much is that going to tell you?In page 3 of the article Stars15K links to above teh basic types of laser spectroscopy are introduced - Raman spectroscopy looks the most promising - some light has its wavelength changed by interaction with what it hits - but from the wiki page article it looks like it would be useless in open air at a range of 10's of thousands of feet - the intervening atmosphere would obliterate the miniscule changes that you need to detect.the othjer methods are fluorescence - which will only be useful if the target does actualyy fluoresce, and "Laser ablation inductively coupled plasma optical emission spectroscopy (LA-ICP-OES) " - which requires making a plasma so is currently restricted to labs.I had always assumed there was some method of figuring out the make-up of atmospheric aerosols because it is done for variosu reasons already - am I missing something??Edit: Looks like current methods for determining composition still require actually catching the particles in eth 1st instance then analysing them - see this paper from 1999