Thread by @BadAstronomer

The Universe MUST have a sense of irony, else why are so many things at their most beautiful when they die?

syfy.com/syfywire/gorge…

1/n Writing about planetary nebula like that one always makes me a bit wistful. For three reasons.

One is that I when I took out my ‘scope as a kid, the very first thing I’d look at on summer nights was the Ring Nebula.

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2/n Another one near the Ring is the Dumbbell, which is also theoretically easy to find, but it was always stubborn and liked to stay hidden. Even now I sometimes struggle to get my ‘scope pointed at it. It’s my astronemesis.

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3/n In the 70s and 80s planetary nebulae weren’t a big topic of study. Even long exposure photos didn’t show much detail, and most people thought we understood them well enough. Big expanding spherical shell bubbles of gas. No biggie.

4/n Then digital cameras were invented. They allowed us to see extremely faint structures as well as bright ones. And suddenly these nebulae were a lot more complicated then we thought. They aren’t spheres. They’re elongated. Barrel-shaped. Hourglasses.

5/n I mean, seriously. They were *bizarre*. Far from understanding them we suddenly realized we didn’t know WHAT was going on with them.

spacetelescope.org/images/heic151…

6/n What was shaping them? Maybe the central star was actually *2* stars in a tight orbit. The angular momentum - sorry, spininertia - threw off more gas in the plane of the orbit, and that helped shape the winds of gas creating the beautiful structures.

7/n But computer models didn’t quite match. Also about half of all stars in the sky are binary, but far more than half the nebulae were weird. In fact it’s rare to find one that’s spherical!

syfy.com/syfywire/nearl…

8/n So. When this was all happening, when I was in grad school, I became interested in these nebulae. I decided to take a look at the nebula NGC 6826 for my Masters. This is a Hubble image of it.

syfy.com/syfywire/follo…

9/n It has a huge circular outer halo (not seen here) and all that weird structure on the inside. How can that be? Why isn’t the halo as weird as the interior? The halo is older than the stuff you see there, so maybe some mechanism changed as the star died.

10/n My advisor had an idea. We know stars expand as they die. Maybe it had planets close in. It consumed them and they spun it up as it died. So the old halo was expelled before that, and all that weird stuff was created after, when the star rotated more rapidly.

11/n This was in 1990. We didn’t even know if other planets even existed! But he predicted massive planets very close in. We added a section explaining this in my Master’s paper.

… and he was right. Five years later the first hot Jupiters were found.

12/n So that’s the second reason I’m a bit wistful about planetary nebulae. I studied them back in the day. I even got my PhD studying a particularly weird one.

syfy.com/syfywire/30-ye…

13/n And the 3rd reason? As I mention in the original article in this thread, when the Sun dies it’ll make one. That wasn’t known for a long time, since you need certain conditions to make one, and we didn’t know if the Sun could do it. Now we do know.

syfy.com/syfywire/good-…

14/n That won’t happen for 7 or so billion years.

But… when I wrote my 2nd book, “Death from the Skies!”, I had a chapter in there about how the Sun dies. I did a LOT of research for it.

penguinrandomhouse.com/books/301689/d…

15/n I came to understand how the Sun live, and how it will die. It became very real to me, as real as walking outside and feeling the warmth of sunlight on my face. Sure, it won’t happen for eons, but the Sun *will* die someday. And when it does it will create beauty.

16/n So whenever I write about planetary nebulae, all of these things crowd for attention in my head. Observing as a kid, studying them as a young adult, applying that knowledge later in my career in my writing, and understanding the inevitability of stellar lifecycles.

17/n Who wouldn’t be wistful then? I hope I am to be forgiven if sometimes I wax on about them.

But there’s a fourth reason, too. It doesn’t make me wistful so much as amazed. Awed, I suppose. We’ve come so far studying these incredible objects. We know so much more about them.

18/n But it’s just their beauty that overwhelms me sometimes… as well as delights me. I’m nerd. I can’t help it.

I mean, seriously: How can you not be excited to see something like THE FLAMING SKULL NEBULA?

syfy.com/syfywire/flami…

19/n So I will continue to write about them. They’ve woven their way throughout my life, and I hope they continue to do so. They are among my favorite things in the heavens, and it gives me great joy to share that with you.

20/20 I’ll leave you with this: A link to page after page of Hubble observations of these glorious objects.

Enjoy.

hubblesite.org/images/news/34…

OK, fine, 21/20. A reminder: This all started with today’s article about a Very Large Telescope image of Abell 36. I waxed on a bit in that one, which is why I’m in this mood.

syfy.com/syfywire/gorge…