Starship Asterisk*

Boomer12k wrote:
I am wondering if gas and dust "knotted up" as the expanding shell hit the interstellar medium... it would push away lesser dense material and areas, and leave....well...."streaks".... just my guess at the moment.

• Probably an earlier ejection stage threw out (up?) a slow moving shell that was overtaken by a later ejection shell.

https://en.wikipedia.org/wiki/Helix_Nebula wrote:

[b][color=#0000FF]Closer view of knots in The Helix Nebula.[/color][/b]

---

<<The Helix Nebula was the first planetary nebula discovered to contain cometary knots. Its main ring contains knots of nebulosity, which have now been detected in many nearby planetaries. These knots are highly radially symmetric (from the PNN) and are described as "cometary", each centered on a core of neutral molecular gas and containing bright cusps (local photoionization fronts) towards the central star and tails away from it. All tails extend away from the PNN in a radial direction. Excluding the tails, they are (very approximately) the size of the Solar system, while each of the cusp knots are optically thick due to Lyc photons from the PNN. There are more than 20,000 cometary knots estimated to be in the Helix Nebula.

The excitation temperature varies across the Helix nebula. The rotational-vibrational temperature ranges from 1800 K in a cometary knot located in the inner region of the nebula are about 2.5′ (arcmin) from the central PNN, calculated at about 900 K in the outer region at the distance of 5.6′.>>

ellipseshadow wrote:The plural of gas is gases. Gasses is a verb. The correct word to use in this article is gases.

ellipseshadow wrote:The plural of gas is gases. Gasses is a verb. The correct word to use in this article is gases.

bystander wrote:

geckzilla wrote:

ellipseshadow wrote:
The plural of gas is gases. Gasses is a verb. The correct word to use in this article is gases.

I do not share this usage constraint. Apparently neither does Merriam-Webster https://www.merriam-webster.com/dictionary/gasses

"gasses" is an acceptable variant of the plural form of "gas", especially in British spelling.

https://en.wikipedia.org/wiki/Gaslighting wrote:
<<Gaslighting is a form of manipulation that seeks to sow seeds of doubt in a targeted individual hoping to make them question their own memory, perception, and sanity. The term originates in the systematic psychological manipulation of a victim by the main character in the 1938 stage play Gas Light and the film adaptations released in 1940 and 1944. In the story, a husband attempts to convince his wife and others that she is insane by manipulating small elements of their environment and insisting that she is mistaken, remembering things incorrectly, or delusional when she points out these changes. The original title stems from the dimming of the gas lights in the house that happened when the husband was using the gas lights in the attic while searching for hidden treasure.>>

bystander wrote:

ellipseshadow wrote:The plural of gas is gases. Gasses is a verb. The correct word to use in this article is gases.

"gasses" is an acceptable variant of the plural form of "gas", especially in British spelling.