At http://phys.org/print312133436.html … it might have been a damp squib for the EU people as Comet ISON has disappeared, blown to smithereens as it approached too close to the Sun, but it has actually come up with an intriguing bit of information. Japanese astronomers who monitored the comet during its bright outburst in the middle of last November, at the Suburu Telescope's High Dispersion Spectrograph, detected two forms of nitrogen – one of them a rare isotope. This is a bit reminiscent of some ideas expressed by Allen and Delair and the role of nitrogen in the instant freezing of the mammoths (going by memory rather than physically checking out their book and various articles from SIS journals). Be that as it may, as it is not part of the story herewith, they also detected ammonia (which contains a high level of nitrogen). For the significance of ammonia and comets you need to check out Mike Baillie's book, 'New Light on the Black Death: The Cosmic Connection' (Tempus, 2006), a really interesting book that describes ammonia as an indication of comet involvement (or comet fragments) as in 1908, the year of the Tunguska atmospheric explosion, ammonia was found in ice cores – and on a number of other occasions too (a surprising number in fact). The ammonia presence doesn't always conform with low growth tree ring events – which indicates volcanoes are also involved (if not the major player).
There are thought to be two distinct reservoirs of nitrogen in the solar nebula, a massive and dense cloud of gas from which our solar system may have formed – and evolved. Ammonia is the most abundant nitrogen bearing volatile in cometary ice – and one of the molecules in an amino group closely related to life itself. In other words, the two different forms of nitrogen that had been on ISON may have a link to life on Earth – and now it has been dispersed into space. Ammonia is actually the major carrier of nitrogen in a comet – and Baillie has described how it was dispersed into the atmosphere of the Earth by close encounters with comets or their prodigy.