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The Observer’s Notebook, a podcast by the Association of Lunar & Planetary Observers, kindly asked me to do an interview with them, and it’s now live!

Host Tim Robertson and I talked about my history with astronomy and skepticism, doing science movie reviews, misinformation, and what it takes to be an effective science communicator. It was fun, and I hope you give it a listen!

M82 is a relatively nearby galaxy, just 12 million light-years away (for comparison, the Andromeda galaxy, the nearest big spiral to our own, is 2.5 million light-years distant). It’s a weird thing: originally classified as an irregular galaxy — meaning one with no overall shape, just a mess — it’s now known to be a small spiral galaxy that we see nearly edge-on, making it look elongated, hence the nickname the Cigar Galaxy.

A new JWST image doesn’t really reinforce that name, though. Because ye GADS that’s not at all what I see in it:

Woof. An utterly spectacular high-resolution 15,000 x 10,000 pixel image is available as well, and yeah, you want it. It’s incredible.

What you’d think of as the main body of the galaxy itself is the white smear of light going horizontally across the image. That’s the combined light of billions of stars. Most are so close together that, from our distance, they just look like a continuous glow. However, JWST’s keen vision can resolve a lot of them, and in fact about 16.5 million individual stars can be seen in the original scientific data.

But what’s that stuff erupting out?

M82 is a starburst galaxy, one undergoing a highly fecund episode of star birth. On average, our Milky Way converts about 1 – 2 times the sun’s mass worth of gas into stars every year (low-mass stars are the most common, so this means stars are born at a rate of very roughly five per year). M82, despite being smaller than the Milky Way, has a star formation rate ten times higher! It’s likely that some time in the past it passed by its larger spiral neighbor M81, and the gravitational interaction shook M82, causing gas clouds to collide, collapse, and elevate its stellar birth rate.

Most of that occurs in the core of the galaxy. A fraction of these newborn stars are high mass (a dozen or more times the sun’s mass) and very luminous. They blow out an intense wind of material, especially when they start to die, which only lasts a few million years. As they swell up into red supergiants they blow huge clouds of carbon and silicon (together called dust) into space, which in visible light are opaque. However, in infrared light that glows, and the combined winds of millions of these stars create those two huge columns of material blowing outward, up and away from the galactic disk (images from the mid-20^th century made it look like the galaxy was exploding — like zillions of supernovae were occurring in the core — and a lot of scifi was based on that erroneous interpretation).

Most of these stars are forming in immense groups called super star clusters, containing hundreds of thousands of stars. An earlier JWST image from 2024 (which I wrote about in BAN #726) shows the winds blowing outward in tendrils from these clusters, which merge together farther away to form the two immense gales of material seen in the new image.

So it’s not so much the Cigar Galaxy, or even the Exploding Cigar Galaxy, but the Double-Headed Infrared Broccoli Galaxy. Well, it looks that way to me.

Hubble observed M82 as well in 2006. The tendrils are visible but not nearly as prominent; this image shows hydrogen gas glowing red, and there’s far more dust than gas in the winds so they’re not as prominent.

One thing that always gets to me in shots like these. The M in M82 stands for Messier; Charles Messier (MEZZ-yay, more or less) was a French comet hunter in the 18^th century. He kept finding faint fuzzies in the sky that interfered with his hunt, so he catalogued them as a way to avoid them. The Messier catalog is now a must-see list of objects (like clusters, nebulae, and galaxies) for amateur astronomers, those being among the biggest and brightest objects in the sky.

I’ve seen M82 myself in my own ‘scope, and in fact saw a supernova in it in 2014. M82 is small in a wide-field eyepiece, but with moderate magnification it’s not all that much different in apparent size than what you see in the JWST and Hubble images.

That blows me away. Those big ‘scopes have incredibly keen vision, so they can see details that are very small and invisible through smaller telescopes (the images you usually see are compressed, but the high-res version gives you a pretty good hint at the details available). Hubble and JWST generally have to take multiple images of larger objects, scanning them so astronomers can put together a mosaic that shows the whole thing.

That’s true here. The detail is incredible. Most distant galaxies are smaller in the sky, and lack the sharp structure we can see in nearer galaxies that appear bigger. Since Messier objects are among the biggest, you can always count on a jaw-dropping shot when JWST and Hubble take a peek at something that starts with that M. Whenever one of them shows up in my inbox I know I’m in for a treat. 

One I can’t wait to share with all y’all, too.

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