Issue 600! And a way cool brain-destroying JWST shot of the cosmos

August 7, 2023   Issue #600

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About this newsletter

Ooo, meta. Bonus: Subscription sale!

600 is an interesting number. It’s a pronic number, meaning the product of two consecutive integers (in this case, 24 x 25). It’s a 10-Harshad number, which means when you write it out in base 10 (i.e., “600”) it’s evenly divisible by the sum of its digits in that base (so 6 + 0 + 0 = 6, and 600 divided by 6 is exactly 100 with no remainder).

The Roman numeral for 600 is DC, and I’m in Washington DC as I write this issue. Huh!

But more importantly, it’s the number of issues I’ve published of this here newsletter! So welcome to Issue DC (or תר in Hebrew). AKA BAN #600.

Round numbers are funny things, aren’t they? We happened to evolve ten fingers, so we count in base 10, and when the odometer rolls over to some largish number ending in one or more 0s our brains flood with chemicals and we feel nice. It seems weird written that way, but hey, we feel nice, and that’s real enough.

So I’ll take a moment — as I’ve done with issues 100, 200, 300, 400, and 500 — and thank you all sincerely and whole-heartedly for reading this. I sit in my house (or, in this case, a friend’s house; see the next section below) in my PJs writing about space, astronomy, climate, scifi, music, or bed-making, and as of this moment nearly 19,000 of you read it. And over 1,600 pay for it!

That’s phenomenal. And, honestly, critical for my life. After losing my job last year the folks who paid for subscriptions to this newsletter were a lifeline for me until I could scrape enough gigs together to pay my bills. That means the world Universe to me. 

To show my appreciation in another way, I’m having a 600th Issue sale on subscriptions! For the next week, up to Monday August 14 at noon(ish) Eastern US time I’m cutting the rates by 25% (why 25? Because it’s one of the two numbers that make 600 pronic, and also because taking 600% off might not be a feasible marketing scheme).

This means monthly subscriptions are US$3.75, and an annual signup is $37.50 (Galaxy Class subs not included). A pittance! Less than the amount you’d spend on a kilo of platinum. By a lot. Do you even know how expensive new cars are? This is a lot cheaper.

So thanks if you sign up, thanks if you already signed up, and <waves vaguely in every direction> thanks again to everyone who reads this. If it weren’t for all y’all I’d just be some weird guy shuffling electrons around for no reason. But I’m a weird guy with a reason. A lot of them.

Personal Stuff

Because I’m a person

Speaking of sitting in a friend’s house in my PJs, here’s an update on my travels.

In early July my wife and I sold our house in Colorado, and in the time since we’ve been driving hither and yon (mostly yon) to visit friends and family. We can’t move in to the new house in Virginia until September, so over the past few weeks we’ve set up temporary shop in Minneapolis, Myrtle Beach, Baltimore, and DC. We’ll take another voyage up to Baltimore to hang out with my sister and her husband before taking the last leg of our trip to Charlottesville, where we’ll be in an AirBNB for a while to manage the final bits of the move locally.

It’s been going OK, with the usual hiccups and bumps and slow-motion disasters you get with any cross-country move. But the high points have been great, including seeing my daughter for the first time in far too long, visiting other family folks, and generally not having to do yard work and dishes.

There have been loads of inconveniences and issues, some bigger than others, but overall I’m trying not to let them take away from the ultimate goal of having a new place in which to settle down in the state my wife and I grew up in.

And hey, the sky keeps turning above us, right? Our greatest successes and most abject failures are smaller than quantum fluctuations compared to the Universe… but also of huge importance to each of us as human individuals. It’s possible to hold both of those truths, and they’re both sometimes I like to be reminded of.

So hey, why not do so now? I can’t have a 600th issue without some astronomy in it, so here’s a fun image to crush your brain.

Astro Tidbit

A brief synopsis of some interesting astronomy/science news

Back in 2012, astronomers discovered a huge and very distant galaxy cluster, literally a collection of hundreds of galaxies. Its light takes over 7 billion years to reach us, so we see it when the Universe was a little less than half its current age. It has a total mass of 2 quadrillion times the Sun’s mass! A big galaxy has maybe a trillion times the Sun’s mass, so this cluster has a lot of galaxies in it.

The cluster’s official name is ACT-CL J0102-4915, but they nicknamed it El Gordo (the fat one) due to its mass. It was discovered using observations from Chandra (in X-rays), the Atacama Cosmology Telescope (in millimeter wavelengths, similar to the kind your microwave uses), and the Very Large Telescope (visible light). Since then it’s been observed by Hubble, too.

Astronomers just released a new set of observation from JWST, and they’re stunning. Check it out!

The first thing that will blow your mind: Pretty much everything in this image is a very, very distant galaxy. I think only about a dozen or so objects are stars in our Milky Way, a few thousand light-years away. Everything else is billion of light-years distant!

This is the largest such cluster known at this distance. But the second thing to blow your mind is that it’s not the most distant object in this image! A lot of these galaxies are much farther away. How do we know? When the light from a background galaxy passes through a cluster on its way to us, the gravity of galaxies in the cluster distorts the light, bending the path as the gravity bends space. This is called gravitational lensing, and I’ve written about it many times.

There are lots of characteristic shapes to lensed background galaxies, like arcs. You can see several in the image, including the big narrow one in the middle that of course they nicknamed La Flaca (the thin one, or more properly, the skinny one). It’s light took nearly 11 billion years to reach us, so we see it when the Universe was less than 3 billion years old.

Another common lensing effect is multiple images of one object, and in La Flaca astronomers found three images of a single red supergiant star! This is the farthest this kind of star has ever been seen, unsurprisingly. We’ve seen blue supergiants this distance before, but not red ones. These are stars are different stages in their lifetimes, and these images tell us about how stars behaved back in the day.

Another strange object to the upper right is called El Anzuelo (the Fishhook), for obvious enough reasons:

This is another case of lensing, where (presumably) the two galaxies in the middle of the Fishhook are doing the distorting. The red color of the distorted galaxy is likely due to a combination of a lot of dust inside it that scatters away blue light, letting red pass through, and also its huge redshift. As the Universe expands, galaxies are carried along with it, and the farther away they are the faster they move away from is. This imparts something very like a Doppler shift to their light, shifting it to longer wavelengths. In this case the galaxy is very bright in infrared, which is exactly the kind of light JWST sees, so it looks very bright.

There’s a lot more to see here, but you get the point.

If you look at the older Hubble image these galaxies are barely detectable. In fact a large number of the galaxies in the JWST image are not visible to Hubble because they’re so far away their light has been shifted well into the infrared, which Hubble wasn’t designed to see. In this way, the two telescopes (plus the others that made the discovery) can be used in concert to give us a much better view of the early Universe.

Images like this are simply brain-stomping. They show us the Universe in a way we couldn’t see before JWST, or at least could only see in vague terms. JWST’s huge mirror allows us to see these faint galaxies in detail, and from them we will learn far more about what our cosmos was like when it was young.

And that thought’s a great way to celebrate the 600th issue, I should think.

Et alia

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