While the situation is grim at NIH, it's closer to catastrophic at NSF. They're just not able to move any money out the door. It appears OMB has them on lockdown. www.science.org/content/arti....
A million new SpaceX satellites will destroy the night sky — for everyone on Earth
theconversation.com/a-million-ne...
Londo Mollari, the Centauri ambassador to Babylon 5, played by Peter Jurasik. In the photo a man in a fancy uniform raises a glass, likely giving a toast, with plants and a irregular set of blue neon lights in the background. His hair is arranged such that the front half of his head is bald, then about 10 cm of hair fans outward perpendicular from his head, in a manner somewhat reminiscent of a trifoil hat worn with one point at the back of the head.
Due to a poor choice of headphone placement, my hairstyle for much of today may best be described as the "Londo Mollari"
Technically kind of true (the best kind of true)!
Of course, speaking as one such nerd, not every cubic parsec is equally interesting (and you need about 55 more 9's 👀).
🔭
A graph! x-axis is years 2018-2026.3; y-axis is log-scaled "Captures per day" referring to photos/videos taken by my phone. A very noisy blue dataset labelled "daily" is shown, along with a 30-day mean, shown in orange. 3 events associated with step changes in the capture rate are shown - "Adopted Cats" late 2020, "Kid born" mid-2022, and "Kid discovers he can take photos on phone" this past week.
Number of photos or videos taken by my phone per day over the past 6 years.
His understanding is still based on individual fruits:
"Is apple a tropical fruit?"
"No, apple is a temperate fruit!"
I guess we have to track down some lingonberry juice!
Following extensive discussions regarding the nature of "tropical juice" over the past several days, the kid has deduced the existence of "temperate juice."
"Rocket launches already contribute to climate change and ozone depletion. Scaling them up to deploy a million aircraft-sized satellites would push upper-atmosphere heating and ozone loss far beyond previous estimates, with the steady burn-up of dead satellites compounding the impacts." 🧪🛰️🚀
New article out about what a million satellites could do to our atmosphere. It's bad. theconversation.com/a-new-space-race-could-t...
Excellent piece from @astrokiwi.bsky.social @sundogplanets.mastodon.social.ap.brid.gy & Laura Revell.
This one sentence is the crux of it all 👇
"There is no public mandate for a single company in one country to make changes on that scale to the planet’s atmosphere."
Highly recommended.
🔭🧪
Alerts are flowing from Rubin Observatory!
There will be a proper press release in the coming hours, please see all the details then, and meanwhile, your favorite alert broker probably has public data available to peruse *now*!
We are up to well over 20k alerts after 20 min on sky 🔭
A line curve showing number of awards for fiscal year 2026 compared to fiscal years 2021-2025 across NSF. The fiscal year 2026 curve lies well below curves for other fiscal years.
NSF Update
Funding curve overall. A little bit of progress in the past week, but only a little bit.
Now by Directorate...
1/11
I have student projects available for all levels!
Interested in simulating star formation and interactions with the star-forming cloud? Have a look at these!
I work with students to align the project to their skills, interests, and academic level. 🔭✨#Astronomy
rajikalk.github.io/html_pages/s...
death by preventable disease is an inevitable and even desired outcome of concentration camps. in every era of concentration camps people have died of typhus, which is a disease of privation and enforced crowding. this illness is intentionally inflicted
A poster announcing details of Carl’s talk at UC on Feb 13th. Title “ information foraging in a social media world”
Pleased to say that Carl Bergstrom (@carlbergstrom.com) will be speaking at the University of Canterbury on 13th Feb!
He is hosted by @tepunahamatatini.bsky.social come see him at noon in Jack Erskine 441!
I felt a strong kinship with the people offering $50 for such a sandwich from the OP.
The meme of Angela Kinsey appearing quietly behind Dwight Shrute from the Office (US). In the first panel, Dwight is enjoying something, and is captioned "READING THE DEMON HAUNTED WORLD". Angela is labelled "MENTION OF THE 1974 NOBEL PRIZE WITH NO ACKNOWLEDGEMENT OF BELL". In the second panel, Dwight sees Angela and is surprised, captioned "F**k"
Anyone else have this experience?
An artist's impression of a brown dwarf, from NASA/JPL-Caltech.
Brown dwarfs are "failed stars" - they never got enough mass to burn hydrogen in their cores, or at least not enough to supply the energy they radiate away at their surface. But what happens if you add enough mass to a brown dwarf to push it over that threshold in mass? Does it become a star? 🔭 🧪 🧵
In our models we can basically describe it just in terms of the amount of entropy that needs to be filled in (to restart convection) relative to the luminosity (Lnuc) available to do that heating. But we only explored a couple simple accretion histories, so this could well be an oversimplification!
Figure 3 from the paper. It's a version of the cartoon diagram shown elsewhere in the thread, but made with numerical stellar models. Each model is coloured by its fate, with longer frozen core timescales corresponding to yellower colours, and shorter corresponding to bright pink. The closer the objects end up in this space to a particular locus of points (not shown) where Lnuc=Lsurf, the longer the frozen core lasts.
The accretion history can matter if it takes long enough (>1 Gyr, i.e. the thermal timescale) that the internal state of the star changes during accretion. Otherwise the time that the core remains frozen is set by how close the object ends up to the Lnuc=Lsurf line.
Mostly the latter! To unfreeze the core you need to put in enough energy to raise the temperature to the point that convection can resume, and that’s set by how degenerate the core has been allowed to get.
For more, including how to actually find these objects, check out the paper arxiv.org/abs/2601.10908! (and recruit Jaime to your PhD program!)
Figure 1 from the paper, showing how the erstwhile brown dwarfs evolve. The coloured arrows represent the paths the different stellar and substellar objects take as they evolve on a plot of mass against ψ, the thermal energy per particle in units of the Fermi energy in the star’s core. Lower values of ψ indicate colder and more degenerate cores. The separately coloured regions and their corresponding outline arrows indicate what direction an object would move. In the pink region within the parabola, objects have a nuclear luminosity, Lnuc, greater than their surface luminosity, Lsurf and they evolve to the right as their cores heat up. In the blue region, Lsurf > Lnuc, so objects evolve to the left as they radiate more energy than they generate. The black parabola is where Lnuc = Lsurf . The solid right-hand side of the parabola represents the main sequence; it is stable to perturbations in ψ. The dashed left-hand side is unstable. The lowest mass on the parabola is the hydrogen burning limit, MHBL. The arrows for the red dwarf and brown dwarf are horizontal as these objects do not change their mass throughout their lives without an outside influence. Maroon, pink, and beige dwarfs begin as brown dwarfs and evolve leftwards until an episode of mass accretion results in them splitting off from the brown dwarf arrow vertically, at least in the case of fast accretion. When accretion has stopped, they then evolve horizontally to the left or right. Maroon dwarfs, like red dwarfs, evolve left and settle on the main sequence. Beige dwarfs end up above the hydrogen burning limit, but outside of the parabola, and so evolve left like a brown dwarf, never reaching the main sequence. A pink dwarf is located inside the parabola when mass has stopped accreting and then evolves to the right to settle on the main sequence. The ‘frozen cores/plateaus’ region in the parabola is the area in which a subset of our pink dwarf models have a frozen core or luminosity plateau
They may spend ~a billion years as their core heats up and "unfreezes", while they remain dim on the surface. And naturally, as beige+red dwarfs we call these pink dwarfs.
But there's an interesting intermediate case, where you wait a while but not quite long enough to make it to beige dwarf territory. These things will eventually become stars, but they take their time.
Meme of a guy in a red uniform shirt sweating and deciding between several buttons. The guy has a brown circle obscuring his face and is captioned "Brown Dwarf Gaining Mass". There are three buttons labeled "Pink", "Beige", and "Maroon"
If you add mass early, you basically take a brown dwarf and put it in a region of parameter space that is red dwarf-like. So naturally we call these maroon(~ red+brown) dwarfs. These are basically indistinguishable from ordinary low-mass stars as far as we can tell.
A text meme. 1. Be a brown dwarf 2. Add mass 3. ?????? 4. (strikethrough: Profit) Become a star!
But what if you're impatient and add the mass earlier? In a new paper led by University of Canterbury student Jaime Luisi, we run some simulations to find out! arxiv.org/abs/2601.10908
Remarkably, it depends! As brown dwarfs age, their cores get colder and more degenerate, and if you wait long enough to add the mass, the star doesn't ignite, it just remains essentially like a brown dwarf. These things are called beige dwarfs (because they're brown- and white-dwarf like).
An artist's impression of a brown dwarf, from NASA/JPL-Caltech.
Brown dwarfs are "failed stars" - they never got enough mass to burn hydrogen in their cores, or at least not enough to supply the energy they radiate away at their surface. But what happens if you add enough mass to a brown dwarf to push it over that threshold in mass? Does it become a star? 🔭 🧪 🧵
Introducing my new service to generate retrospectives: Orpheus
