Robert Farrar sent in four links, the first of which concern findings from the DAWN spacecraft visit to the asteroid Ceres – now written up and published in the journals. See for example http://news.sciencemag.org/space/2015/12/dwarf-planet-ceres-may-harbor-c… …. http://www.astrobio.net/topic/solar-system/meatoritescomets-and-asteroid… …. and http://universetoday.com/115634/stinky-rosettas-comet-smells-like-rotten…
Close-ups of the bright spots on Ceres look remarkably like the hollows on Mercury as revealed by the MESSENGER mission. The bright spots on Ceres are supposedly due to water ice sublimated in the past leaving behind a sort of salt crust (but read here epsom salts rather than culinary salt). However, no actual water ice has been detected on Ceres although some of the bright spots in a crater could be emitting water vapour (more commonly associated with comets). The presence of ammonia on Ceres is remarkably similar to what Rosetta obsrved on Comet Churyumov-Gerasimenko and is in fact, in tune with the electic model of comets . See also Mike Baillie's book, 'New Light on the Black Death' where he too associates injections of ammonia into the atmosphere of the Earth with the signature of comets (even in fairly recent times).
The article from Astrobiology magazine is probably the most informative piece as we learn more about Ceres from the studies. The asteroid cum comet has 130 bright areas – was this due to outgassing activity? (in the past). Again, like comets the surface of Ceres is dark – described as similar to fresh asphalt.
Meanwhile, hydrogen sulphide was detected in Comet Churyumov-Gerasimenko (by the Rosetta mission) as well as ammonia and formaldehyde and traces of hydrogen cyanide and methanol. However, these molecules are small in comparison with the amount of water vapour and carbon monoxide on the comet (and streaming into space). One can see that a cloud of material with an origin in a comet could well have been a lethal brew it had become tangled in the upper atmosphere of the Earth – is that possible? Mike Baillie suggested something like this in his book (above).
At www.space.com/28884-rosetta-comet-nitrogen-discovery.html … the focus here is that molecular nitrogen was found on Comet Churyumov-Gerasimenko. Nitrogen is also common on planets and moons in the outer solar system and the implication assumed is that the comet originated in the further reaches of the solar system. However, it seems there was a lot less nitrogen than expected (from models) which leads into an attempt to understand why this might be so.
At www.space.com/30961-modern-mystery-ancient-comet-spewing-oxygen.html … again concerns data beamed back by Rosetta – oxygen streaming off comet Churyumov-Gerasimenko (in the gas or coma tail). This also upsets models and assumption that oxygen was present in the early solar system and then went absent – only to reappear much later. Oxygen is supposed to have been annilhilated during the formation phase of the solar system yet here we have oxygen present in a comet, and more importantly present in the coma (sometimes described as the atmosphere of said comets). Obviously, this requires some navel gazing.