BAN #307: New season of HtUW, A gorgeous spiral galaxy

21 March 2021   Issue #307

March 22, 2021

[The planetary nebula M 2-9, winds from a dying star. Credit: NASA / ESA / Hubble Legacy Archive / Judy Schmidt]

Upcoming Appearances/Shameless Self-Promotion

Where I’ll be doing things you can watch and listen to or read about

If you’ve ever wondered how the Universe works, do I have a TV show for you! The new season (the ninth, holy moly) of “How the Universe Works” will air on The Science Channel starting on March 24, 2021 at 9:00 p.m. Eastern time! That’s in two days as I send this newsletter issue out. The first episode is a black hole special, and the other episodes of the new season will air every Wednesday. It will also be on the Discovery+ app (it drops at 4:00 a.m. Eastern, so earlier than on TV).

[“How the Universe Works” logo. Credit: Discovery Network]

I really enjoy working on this show, which is why I always say yes when they ask me back; I’ve had the delight and honor to be in every season, and I even did a little science consulting on a few episodes this season as well, which was a lot of fun. I’ve watched a lot of astronomy series over the years, and HtUW is one of my favorites. Great cast, great writing, and the special effects always blow me away.

So tune in, or set your DVRs! If I get any more info on air times or how to watch, I’ll be sure to mention it on Twitter.

Blog Jam

What I’ve recently written on the blog, ICYMI

[Artwork showing a clement, warm, and wet ancient Mars, about three billion years ago. From Thursday’s article. Credit: Getty Images / Mark Garlick / Science Photo Library]

Monday 15 March, 2021: Zzzzzt! Mars might be sparky

Pic o’ the Letter

A cool or lovely or mind-bending astronomical image/video with a short description so you can grok it

I do love a majestic spiral galaxy. Don’t you? If you’re not sure, then try this one on for size… which I mean literally as you’ll see in a sec.

[The spiral galaxy NGC 3261. Credit: Adam Block]

That is NGC 3261, a spiral galaxy located about 100 million light years away in the constellation Vela, taken by my friend and amazing astrophotographer Adam Block. It’s gorgeous! Beautifully defined spiral arms, dotted with red blobs indicating huge clouds of hydrogen gas busily forming stars, and blue due to massive, hot blue stars that are born there. Massive stars don’t live long, just a few million years, so where you see blue you know the galaxy has been busy cranking stars out.

When massive stars die they explode, and in fact two supernovae have been seen in NGC 3261, one in 1997 and another in 2008. The earlier one was from a massive star at the end of its life, while the other was from a white dwarf exploding, what we call a Type Ia supernova. I’ve written about this kind many times; here’s an article that describes them in some detail.

NGC 3261 is a barred spiral; it has a straight rectangular bar of stars going right through its center; in Adam’s image it’s vertical. Many spirals have this feature. The Milky Way does, in fact. It’s an outcome of the way gravity works in a giant disk of stars; the way stars can move around can be surprising and nonintuitive. Bars can act like a funnel for gas outside the center of the galaxy, with the gravitational influence of it channeling gas down into the core. Sometimes this can create an elevated star formation rate in the galaxy, too, since all the gas gets corralled into one place. It can also feed it to the supermassive black hole that’s in the center of every big galaxy, too, causing it to grow bright. We call galaxies like that active galaxies.

I imagine the Milky Way looks quite a bit like NGC 3261 if we could see it from a million light years away. Funny, too: NGC 3261 happens to be in a part of the sky where we have to look out through a particularly rich part of our own galaxy’s disk, so there are a lot of stars around it. Those are all inside the Milky Way, and we see past them across intergalactic space to the other galaxy.

I was happy to see Adam also posted a much wider field view, which really drives this point home:

[A wider shot of NGC 3261. Credit: Adam Block]

Wow! I love seeing galaxies like this! You get enough resolution on it to see the structure and beauty, but also see the context of the sky in which is sits. I am limited in how big an image I can post here, so go to the original image on Adam’s site to see this in its full gorgeousity. There are other, fainter galaxies right around it, making me wonder if this spiral is alone in space or if it has an entourage of smaller satellite galaxies around it. It’s clearly not in a big cluster, or else we’d see lots of other decent-sized galaxies around it.

There is that one nearly edge-on spiral at the top of the image; judging from its size it could be similar to NGC 3261 and a companion as well. So I checked its distance and it’s at almost exactly the same distance, just a bit farther away, so its possible the two are associated.

If you like this shot then you should follow Adam on Twitter, where he frequently links to his amazing deep-sky images. I am always astonished at the work he does.

Et alia

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