JWST M51 image credit: ESA/Webb, NASA & CSA, A. Adamo (Stockholm University) and the FEAST JWST team

This is issue #675 of the Bad Astronomy Newsletter, which is special for two reasons.

One is that 675 is an Achilles number. These are numbers that, once you get their prime factors, you find that the squares of those numbers are also factors. So 675 = 3 x 3 x 3 x 5 x 5 (its prime factors), and 3^2 = 9 and 5^2 = 25 are also factors. Why “Achilles” prime? Because it’s powerful (a pun on the “powers” of the prime factors) but not a perfect power (it’s not some integer taken to the power of another integer, like 25 = 5^2). So it’s powerful but not perfect. Achilles, get it? I love math, and I love puns, and so I love math puns, especially math puns that have other math puns embedded in them. Amazing.

The second reason this issue is special is because it’s the first one I’m sending on the new platform, Beehiiv! I explained why I moved in previous issues (see Issue 674, for example, with links to other issues).

The move from Substack did cause some hiccups, and for that I apologize. A glitch in the migration process meant y’all were sent an email to confirm your subscription. You can delete and ignore that; it wasn’t supposed to be sent. I know it caused a lot of confusion! It confused me too.

To the best of my knowledge, if you’re a free subscriber everything is already done. You’ll now just get these issues through Beehiiv. If you’re a paid subbie then the subscription should have simply moved over here, including the end date. So if you subscribed for one year on, say, July 4, 2023, your subscription will end on July 4, 2024, and you’ll get an email reminding you to resubscribe. You’ll do that through Beehiiv; but the good news is it uses Stripe.com just like Substack did, so you don’t need to set up a new Stripe account. Hopefully the process will be simple. If not, please let me know!

 In fact if you see any problems, please drop me a line. This is all new to me so I can’t guarantee fast results, but I’ll do what I can.

As for Galaxy Class subbies, at the moment there are only two premium levels allowed by Beehiiv, so once your subscription period is up that’ll be that for the GC level, at least until Beehiiv allows the capability to add more. Which reminds me: If you still haven’t received your meteorite, let me know. I know a few more people signed up and I suspect some folks didn’t get theirs, and I’m happy to send them to you. 

You’ll almost certainly find archived posts will be missing images, buttons, and so on. That always happens with migration (I saw it over and over moving my blog from Discovery to Slate to SYFY), so please don’t fret if old issues look funny. I’ll fix them, probably piecemeal when I link to an older issue and see it’s messed up. 

You may also notice some formatting changes in the newsletter, too, meaning it looks a little different. Of course the settings here at Beehiiv are different than Substack, and I’m still playing with them. Over the next few issues I’m sure I’ll be fiddling with that to make the newsletter more readable, or at least more fun to read.

Which is all to say hurray! I’m now publishing through Beehiiv! And also please be patient as we go through the inevitable migration issues.

And, as always, thanks for sticking around and subscribing. I appreciate y’all!

Sometimes when the newsletter issue number rolls over into a nice round number (like something with a couple of zeroes at the end, or, as we math dorks say, “issue number modulo(100) = 0”) I like to change things up banner-wise.

This issue number isn’t special in that way, but given the new platform, I figured why not? I poked around the web for a good image, and then remembered one that was perfect.

So welcome to the new Bad Astronomy Newsletter banner (see above), featuring a phenomenal JWST mid-infrared image of the nearby spiral galaxy M51!

 Normally I’d write a lengthy florid piece about this magnificence, but happily I already have back in Issue 613.

If you want to see the original, here’s the link to the NASA JWST Flickr page with lots of options to get it, including a quite large 4137 x 1551 pixel version. Enjoy.

How about some more good news? In fact, great news!

LISA passed the European Space Agency’s Mission Adoption Review, and is now an official mission ready to cut metal! The Laser Interferometry Space Antenna is a space-based gravitational wave detector, like LIGO and Virgo but much, much larger and more sensitive. Gravitational waves are ripples in the fabric of spacetime created when anything with mass undergoes acceleration, but the more massive and higher the acceleration, the easier they are to detect. LIGO and its collaborators have detected many dozens of black hole binary systems merging, which blast out g-waves.

Since space itself is contracting an expanding, the longer your baseline the more of the effect you can detect. LIGO uses a pair of arms 2 kilometers long. LISA will use three spacecraft flying in formation separated by 2.5 million km, making it way more sensitive. Plus it won’t have interference from seismic disturbances, trucks driving by, and so on.

I wrote about LISA in a BAN #426, when it passed its final design review, and gave an overview of how it works and its history. Back in the very early days of the mission design, my group at Sonoma State University was charged with working on the Education and Public Outreach for LISA, and as the pet writer of the group that meant I had to dig into it, read about it, and write it up for the website and various brochures and such. That was fun, because the tech involved is ridiculously advanced, and feels a lot like Star Trek. The three spacecraft have free-floating masses in them, and when a gravitational wave passes between them the distances between the masses changes a teeny bit. The spacecraft use lasers to measure their relative positions to far less than a nanometer, and from there can figure out where the wave came from and what kind of object created it.

Like I said. Star Trek.

Anyway, NASA pulled out of LISA early on due to irritating (read: political) budget decisions, but I’m glad to say they changed their mind and are now contributing to the project. It’s super cool, so keep your eyes open for news. I will. It’s slated for launch in about 10 years or so. I can hardly wait!

You can email me at [email protected] (though replies can take a while), and all my social media outlets are gathered together at about.me. Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or nine, too. Thanks!