On the other hand, imagine the expanding outer atmosphere of the newly-turned white-dwarf Sun impinging upon the legion of icy cometary objects we KNOW FOR A FACT populate the Kuiper Belt and surrounding Oort Cloud reservoir out to a radius of up to a light-year. Consider further that it is possible for them to have had lots of time to dynamically congregate in loosely-held clusters far from the gravitational influence of any of the major inner planets, and won’t have been frequently disturbed from the rare relatively close encounters of interstellar interlopers (stars and brown dwarfs) over the course of the Sun’s very long 10-billion-year lifespan by then.

It is hard to imagine a hot and sustained (if rarefied) stellar outflow NOT producing these very same kinds of cometary radial structures out of such a populous surrounding flock of icy objects commonly thought to attend most all sun-like stars.

Yet I LIKE the scenario suggested by García-Segura et al in 2006 (and others who suggested it years earlier) as a mechanism for radial structure in ‘planetary nebulae’. It seems to work, but like so many other complex phenomena in nature, one chooses a SINGLE explanation to explain EVERYTHING in a complex phenomenon at one’s peril. Nature isn’t obliged to select a winner out of pathetically limiting dichotomies (excruciatingly dumb “either this or that explanation is correct”) – especially those dreamed up by unimaginative humans. One might as well expect that the deployment of an oak tree is completely dertermined at the genetic level without any input from its environment, as if the acorn had all the instructions that dictated how every branch should grow and every leaf should fall.

While the García-Segura et al scenario may indeed be an important mechanism for radial structure in most cases, I would like to see a lot more work showing how clusters of icy objects in an outer envelope around dying stars CAN’T be responsible for any of the very same beautiful effect.

That work has not yet been adequately addressed.

The ultimate irony here is that if EITHER or BOTH of these two mechanisms are primarily operative – or NEITHER of them are – the phenomenon of crepuscular radiance is NECESSARILY PRESENT ANYWAY! It can’t be avoided because of the obvious variations in the density posed by the cloud clumps we see in such nebulae like the Helix (although the visible effect of a crepuscular contribution to the radial structure might be quite slight compared to that of the primary causes). So there are at least THREE ways of producing or enhancing radial structure in Stellar Terminal Nebulae.

Any creatures living there would certainly have an interesting environment to contend with – although the prospects of any indigenous aliens ( ) surviving their star ballooning into a red giant then becoming a Mira variable and planetary nebula seem remote.

I wonder if the morphology of this planetary could perhaps give us clues as to whether any exoplanets used to orbit the star that has formed Messier 27 existed (or even still exist) – and what their nature might’ve been?

Awesome image there.

At least having a telescope is better than nothing. Lol.
The dumbbell is one of my nightly visits. I usually start with the ring nebula then pan over to the dumbbell afterwards. I love PN also, just amazing beauty in something so destructive.

VinceRN, next time you want to kick your 8″ Newt, give me a call. I’ll come over and exchange your 8″ for my 4″, then you can kick as much as you want.

BA, thanks for posting these!