gully

YouTube video by Flatiron Institute Earl Bellinger: Putting compact objects where they don’t belong...(October 24, 2025)

Talk from Earl Bellinger describing black holes in the interior of stars, and observational consequences:

youtu.be/RW0GX36neKM?...

I suppose this channel is rare enough that we’re not likely to see one on a nearby star in our lifetimes, but still it’d be cool. Also we’re not sure this channel exists.

The planets would still have IR, you could do direct imaging on them, even better if they were young, you’d probably want a high mass host star for the planets to be young enough. The BH removes the host star for you, no coronagraph needed

So there’s the prospect of planets that previously had a host star suddenly orbiting a black hole, but without the destructive phase of traditional HR diagram stellar evolution. Dark Planet systems.

Assumes you have some precursor to predict the accretion event timing, probably wouldn’t work out, free fall time is at least comparable to light echo time, etc. but upside bonus if they were eclipsing before the event, resulting BH could lens the planets if geometry is perfect?

New planet detection technique:
Look for stars that disappear entirely (black holes in interior, cf Bellinger) then look for light echo plateaus from the reflected light of planets.
Apparently ~100 M dwarfs have disappeared consistent with this mechanism. You’d have a few light minutes of signal.

Currently reading the Project Hail Mary book and there’s a ton of astrophysics in it—no spoilers but early on there’s infrared spectroscopy, ALMA, and more. Curious to hear what other astronomers think!

For astrometry, you’re right that better knowledge of the PSF yields benefits in the high SNR regime as well, since asymmetries in the PSF shape need to be understood to account for biases in the centroid. Chromatic effects mean the PSF fitting should help in all cases

Good point, I suppose it depends on the goal— for photometry, aperture-based methods give you comparable results to PSF fitting in the high SNR regime. In the low SNR regime, the background noise dominates the aperture based methods, so PSF fitting boosts delivered SNR by weighting the pixels.

Well said

Neat work on precision PSF modeling of Gaia!

Little known fact: we captured Kepler driftscan PSFs during downtime in the K2 mission. PSF modeling is great boon for low SNR science, extended objects, etc.

Good band name, or maybe a softball team composed in part by punk rock astronomers with a fastball

It’s me

Sans serif math in LaTeX is so satisfying. \mathsf{}

Above all it’s just great to hear Dan’s voice, miss that guy

YouTube video by Flatiron Institute Dan Foreman Mackey: JAX Training

youtu.be/yUAZGR9RwPI?...

@benjaminpope.bsky.social it’s mostly live coding with examples of JAX-isms and some new goodies like context managers for float64

Very cool opportunity to make differentiable physics models for EPRV, work with Ben and co, and live in a cool place. Pretty much a dream job, apply!

Still want a JAX for science conference, where all my JAX scientists at

The sheer joy I felt just now discovering that there is a new Dan Foreman Mackey video about JAX.

standing room only for physics?
faith in humanity restored ✨👏

I still feel like differentiable models are under appreciated, it’s like a magic super power for interpretability and extensibility. Maybe LLM-assisted coding can bring autodiff to more science teams? Still a mental leap to adoption.

Everything becomes so much easier when you can forward model your data

blasé: An interpretable transfer learning approach to cool star échelle spectroscopy Comparison of échelle spectra to synthetic models has become a computational statistics challenge, with over ten thousand individual spectral lines affe…

Looking back on this talk about autodiffable spectral models, there is still so much promise, I’d love to see what folks have been up to in this space!

speakerdeck.com/gully/blase-...

New job opportunity at @stsci.edu: Senior Astronomical Data Scientist for data analysis tools, working closely with my team and me.

This role is very similar to mine. If you have questions, I'm happy to answer them. 🧪🔭

Currently 83% carbon-free energy in Texas right now:
- 40% wind
- 33% solar
- 10% nuclear

Wholesale prices are negative, and 3.5 GW of batteries are charging.
☀️💨⚛️🌎

Over 20 New EVs Are Coming In 2026. These Are The Seven I'm Most Excited About We’ve been waiting for the next generation of EVs to arrive—cheaper, faster, better. Next year, they’ll finally be here.

Despite headwinds, over 20 new EVs are coming to the US market in 2026, including several more affordable vehicles. Can any thrive without federal tax credits? insideevs.com/news/782572/... 🔌💡 🔌🚗

It’s wild that stellar limb effects start to matter at non-negligible fractions of a resolution element on the ELTs!
Challenge… or opportunity!?

Toyota's 1,850-acre EV battery plant is live, but the company says this is just the start Toyota’s $14 billion US battery plant is now up and running. The mega site spans 1,850 acres, or about 121...

The first batteries rolled off the production line at Toyota’s new $14 billion battery plant in Liberty, North Carolina. The plant will produce batteries for hybrid, plug-in hybrid & electric models, which Toyota plans to make up 70% of its sales by 2030 electrek.co/2025/11/17/t... 🔌💡 🔌🚗

Get outside into a dark place if you can tonight - no guarantees, but a possible brilliant display of the northern lights.

Hat tip @wilsonar.bsky.social for this! 🤣