Notices by Prof. Sam Lawler (sundogplanets@mastodon.social)

RE: https://saturation.social/@debcha/116876004663657092

This would be a great sequel to Hidden Figures! I'd definitely watch this movie.

Gosh these predatory journal invites for my April Fool's Day Cow-culation paper https://arxiv.org/pdf/2603.29324 will never stop being completely hilarious

(I should clarify that I don't have enough info to think this is SpaceX. I'm just referencing the only international space junk incident I witnessed, because it was SO WEIRD.)

Lots of people sent me links to this news story (thanks!) Looks like Alice Gorman is the scientist who got roped in to comment this time (she's fantastic, I just think it's funny to see who gets stuck with explaining each space junk fall).

Interesting that the local police took such a cautious stance - probably the right thing to do, though as space debris becomes more common, this will become difficult.

Hopefully some silent SpaceX dudes will show up soon in a UHaul.

https://mastodonapp.uk/@bbcnewsfeed/116867609749430395

Need some ridiculous baby goats using rolled up shade cloth as a scratching post? Yes, you do.

Ok, wrote a bunch of words in various documents and answered a bunch of emails after my bike ride. Now time to try to move the goat fence before the giant pile of thunderstorms gets here (looks like the poor dog is going to have to deal with thunderstorms YET AGAIN).

Muddy but beautiful neighbourhood bike ride. Critters use the roads almost as much as us: I saw footprints from deer, moose, and lots of coyotes (or maybe foxes? I don't know enough to tell the difference from a moving bike)

Cool!! (It hit quite far away, did not hit the barn like this picture implies)

Poor goats. I did not get the fence set up before I got a tornado warning on my phone and decided it was time to go inside.

The tornado warnings in Sask often cover a ridiculously huge area...I could clearly see there was no tornado. But there was thunder starting so... poor goats. They will have to wait until tomorrow for new grass. (They will be fine).

An extremely talented graphic artist (who is here on the fediverse but wishes to remain anonymous, THANK YOU FRIEND) helped me put these space-junk-for-kids pamphlets together! Here's the version that shows the page order as you would read it

Send me a message if you'd like a version that is formatted for folding!

Picked up the printed pamphlets, dropped them off at the Saskatchewan Science Centre.

Bought chicken feed on the way home, unloaded into the barn.

Now time to catch up on a bazillion emails and try to get a few more journalists to write about the CRASH Clock!

WOW what a ridiculous day.

Early CRASH Clock media interview was moved later in the day.

Had 2 excellent conversations about book contracts with amazing professors who have written books.

Took the space-junk-for-kids pamphlet to get printed on campus, had to reformat it, took a break from reformatting to do the delayed interview.

Had to wait a couple hours for printing, so had a nice lunch with my 14yo, then checked out a huge number of nature guidebooks from the campus library.

Does anyone have good recommendations f resources for book authors to learn about book publishing contract basics? #WritingCommunity #amWriting

We originally wrote this paper nearly a year ago. As of last June, the CRASH Clock was at 5.5 days. It's now down to 2.5 days. It was 168 days in 2018, pre-Starlink.

It just keeps dropping as we launch more satellites into orbit.

This metric shows how completely dependent we are on continued perfect operations in orbit. 2/3 of all satellites today are Starlinks, and they performed 300,000 collision-avoidance maneuvers last year. They have done it perfectly so far. How long can that continue?

The CRASH Clock (which is an acronym, I apologize deeply) is our metric for how dangerous orbit is. We download real orbits for everything (satellites, rocket bodies, tracked debris) and calculate how long it would be for a collision to occur if no orbital maneuvers happen.

This is a worst-case calculation. What if everyone suddenly lost control due to a solar flare, a bad software update, or someone hacking Starlink? How long do we have to regain control?

Just in case collisions in orbit aren't depressing enough, here's a super excited, cheery article with so many incredibly enthusiastic quotes from many astronomers about the start of full operations for the Vera Rubin Observatory! And I got to provide the doom-quote about satellites causing serious loss of data (I also provided lots of excited, enthusiastic quotes about science! But doom-quote won I guess...) https://skyandtelescope.org/astronomy-news/vera-c-rubin-observatory-begins-its-long-awaited-all-sky-survey/

SpaceX is owned by the richest dude in the world, a demonstrably horrible person. And SpaceX effectively controls orbit right now.

There are also dozens of other companies planning to launch even more satellites into already-crowded orbit. (Another company I've never heard of just filed today for another 100,000 satellites https://spacenews.com/orbital-files-plans-for-100000-orbital-data-centers/. Fuck.)

Our future ability to make use of incredibly beneficial satellites is entirely in the hands of selfish, horrible billionaires.

The Conversation article above describes a collision scenario more in detail. It takes months to catalogue new debris from collisions, and in the the mean time, additional collisions can happen. That potential collisional runaway is the Kessler Syndrome, the worst-case scenario in orbit (explainer here: https://theconversation.com/too-many-satellites-earths-orbit-is-on-track-for-a-catastrophe-but-we-can-stop-it-275430)

The CRASH Clock is not a countdown to Kessler, but any major collision in orbit, especially in Starlink's super-dense orbit, will be an extremely bad day.

This paper took forever to publish. All the co-authors are astronomers, so we initially started with astronomy journals, and they didn't like it. Not astronomy-enough, I guess. So we tried a space journal instead. Here's the article from Acta Astronautica: https://www.sciencedirect.com/science/article/abs/pii/S0094576526004091

And here's the non-paywalled version on the arXiv: https://arxiv.org/pdf/2512.09643

You may remember I wrote a bunch about this months ago when we first put it on the arXiv. Now it's peer-reviewed, and officially DONE.

Everything in Low Earth Orbit is travelling at essentially the same speed. So you can take this density plot, and turn it in to a close encounters plot. The heart of the paper is doing that calculation in two different ways, one analytic, and one numerical.

In Starlink's orbit, the densest part of orbit, close encounters closer than 1 km happen every half hour or so. 1km sounds like a large distance, but remember the speeds are 7 km per SECOND. That is scary-close.