[quote="Chris Peterson" post_id=288074 time=1544678193 user_id=117706]
[quote=Boomer12k post_id=288070 time=1544673550 user_id=120851]
"Opaque to visible light, dark dust is created in the outer atmosphere of massive cool stars and expelled by a strong outer wind of protons and electrons. "
Does that make "Dust"....Ash??? Or is is something created, not burnt...[/quote]
"Burn" is generally understood as combustion- an exothermic, oxidative reaction. Fire. That is not what is happening in stars. "Ash" is generally understood to be the non-combusted solid residue of combustion.
[b][u]"Dust" is precisely the right word: fine particles of solid material. That is what is produced in stars by various fusion processes.[/u][/b][/quote][quote="https://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbon"]
[float=left][img3="The Cat's PAW Nebula lies inside the Milky Way Galaxy and is located in the constellation Scorpius.
Green areas show regions where radiation from hot stars collided with large molecules and small dust grains called polycyclic aromatic hydrocarbons (PAHs), causing them to fluoresce. (Spitzer space telescope, 2018)"]https://upload.wikimedia.org/wikipedia/commons/thumb/6/64/PIA22568-CatsPawNebula-Spitzer-20181023.jpg/1920px-PIA22568-CatsPawNebula-Spitzer-20181023.jpg[/img3][img3="PAHs are considered possible starting material for the earliest forms of life."]https://www.ultimatemovierankings.com/wp-content/uploads/2015/10/ma-and-pa-22222.jpg[/img3][/float]
<<Polycyclic aromatic hydrocarbons (PAHs, also polyaromatic hydrocarbons or polynuclear aromatic hydrocarbons) are hydrocarbons—organic compounds containing only carbon and hydrogen—that are composed of multiple aromatic rings (organic rings in which the electrons are delocalized). In October 2018, [b][u][color=#0000FF]researchers reported low-temperature chemical pathways from simple organic compounds to complex PAHs[/color][/u][/b]. Such chemical pathways may help explain the presence of PAHs in the low-temperature atmosphere of Saturn's moon Titan, and may be significant pathways, in terms of the PAH world hypothesis, in producing presursors to biochemcals related to life as we know it.
PAHs may be abundant in the universe. They seem to have been formed as early as a couple of billion years after the Big Bang, and are associated with new stars and exoplanets. More than 20% of the carbon in the universe may be associated with PAHs. PAHs are considered possible starting material for the earliest forms of life. Light emitted by the Red Rectangle nebula and found spectral signatures that suggest the presence of anthracene and pyrene. This report was considered a controversial hypothesis that as nebulae of the same type as the Red Rectangle approach the ends of their lives, convection currents cause carbon and hydrogen in the nebulae's cores to get caught in stellar winds, and radiate outward. As they cool, the atoms supposedly bond to each other in various ways and eventually form particles of a million or more atoms. [b][u][color=#0000FF]Adolf Witt and his team inferred that PAHs—which may have been vital in the formation of early life on Earth—can only originate in nebulae[/color][/u][/b].
More recently, fullerenes (or "buckyballs"), have been detected in other nebulae. Fullerenes are also implicated in the origin of life; according to astronomer Letizia Stanghellini, "It's possible that buckyballs from outer space provided seeds for life on Earth." In September 2012, NASA scientists reported results of analog studies in vitro that PAHs, subjected to interstellar medium (ISM) conditions, are transformed, through hydrogenation, oxygenation, and hydroxylation, to more complex organics—"a step along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively". Further, as a result of these transformations, the PAHs lose their spectroscopic signature which could be one of the reasons "for the lack of PAH detection in interstellar ice grains, particularly the outer regions of cold, dense clouds or the upper molecular layers of protoplanetary disks.">> [/quote]