Nereide

Great thread from John Baez! Read it.

In short, with an extraordinarily elegant theoretical reasoning based on relativity, QM, and the known size of atomic nuclei, Yukawa correctly predicted the existence & mass of a new fundamental particle… which was discovered only years later!

🧪 ⚛️ #histsci 1/3

...whose mass he calculated to be intermediate between that of the proton and the electron.

A masterpiece of theoretical #physics! 🧪 ⚛️

Yukawa Paper (PDF): isidore.co/misc/Physics...

3/3

In 1935, Yukawa published a paper titled “On the Interaction of Elementary Particles” (Proc. Phys. Math. Soc. Japan, 17, 48-57)⚛️, in which he proposed a field theory of nuclear forces that predicted a new interaction (today known as the strong interaction) and the existence of a particle...

2/3

Great thread from John Baez! Read it.

In short, with an extraordinarily elegant theoretical reasoning based on relativity, QM, and the known size of atomic nuclei, Yukawa correctly predicted the existence & mass of a new fundamental particle… which was discovered only years later!

🧪 ⚛️ #histsci 1/3

If you like the double-barrelled surname and your partner is on board, go for it now.
The hassle is real, but it's a one-time investment, and in a few months everything will be sorted out.
Good luck, whatever you choose will be fine — the important thing is that you feel comfortable with it.🤞

"The main image at left shows a combined Webb and Hubble view of spiral galaxy NGC 1637. Panels at right show a detailed view of a red supergiant star before and after it exploded. Before exploding, it was not visible to Hubble, only to Webb. Hubble shows the glowing aftermath. Hubble's shorter-wavelength data is represented in blue and green, while Webb's longer-wavelength data is represented in green and red."

🧵On 2025 June 29, the ASAS-SN detected a supernova in NGC 1637 at ≈ 39–40 Mly. 🔭 ⚛️ 🧪

One team searched old archive images & found the star that exploded: the first published detection of a supernova progenitor candidate by #JWST.

Full paper here ➡️ iopscience.iop.org/article/10.3...

#universe 1/8

Can the Most Abstract Math Make the World a Better Place? | Quanta Magazine Columnist Natalie Wolchover explores whether applied category theory can be “green” math.

Hey! Now you can read about my work on applied category theory here on Quanta magazine! And not just me, lots of folks....

www.quantamagazine.org/can-the-most...

...with potentially lethal effects extending up to 50 parsecs (about 160 light-years) for certain types of explosions.

400 light-years is well beyond any serious threat.

A 2023 study indicates a safe distance from a supernova has to be ∼160 light-years: chandra.si.edu/photo/2023/4...

In short, a supernova can cause a mass extinction event at distances typically less than 20 parsecs (about 65 light-years), ...⤵️

The day meetings become your full-time job is the official 30yo glow-up nobody asked for 😀. But wow, excited students make it 100% worth it.

I'm glad! :)

NOTE

- ASAS-SN means All-Sky Automated Survey for Supernovae
- Plateau phase is the long, stable brightness phase of a Type II supernova
- Blackbody is an idealized hot object emitting light based only on temperature

NASA press release:➡️ science.nasa.gov/missions/web...

Image credit: NASA, ESA, CSA, STScI, Charles Kilpatrick & Aswin Suresh (Northwestern), processing by Joseph DePasquale (STScI).

8/8

Carbon-rich dust is unusual for a ~15 solar masses red supergiant (they usually make silicates).

Maybe late mixing or a strong wind before the explosion.

Authors stay cautious: models have assumptions.

7/8

Surface ~3000 K, dust shell ~800 K, dust dims by roughly 5 magnitudes. Hands down the reddest, dustiest red supergiant (RSG) progenitor on record.

This helps explain the old “missing red supergiants” puzzle: the brightest ones may just be super dusty and hidden in visible light.

6/8

Graphite dust matched the data well. Silicate dust didn't: it predicted way too much light at 7.7 microns, no matter how they tweaked the model.

Best fit: the progenitor star is ~100,000 times brighter than the Sun (started with ~15 solar masses).

5/8

Post-explosion Hubble image lines up perfectly with the pre-explosion source.

The star's light pattern (SED = Spectral Energy Distribution) looked strange.

A simple blackbody fit gave ~1470 K — way too cold for any star. So they modeled a red supergiant wrapped in dust.

4/8

Hubble saw the progenitor star very faintly back in 2001 in red/near-infrared light (800 nm).

Then JWST in 2024 caught it bright and clear from 1.5 to 7.7 microns.

That's the longest wavelength ever for spotting a supernova progenitor.

3/8

The supernova, designated SN 2025pht, is a typical SN II (hydrogen-rich), likely in its plateau phase.

Spectrum taken with the 10 m Keck I telescope shows broad hydrogen lines, almost no host-galaxy dust.
But the progenitor itself was buried in its own circumstellar dust.

2/8

"The main image at left shows a combined Webb and Hubble view of spiral galaxy NGC 1637. Panels at right show a detailed view of a red supergiant star before and after it exploded. Before exploding, it was not visible to Hubble, only to Webb. Hubble shows the glowing aftermath. Hubble's shorter-wavelength data is represented in blue and green, while Webb's longer-wavelength data is represented in green and red."

🧵On 2025 June 29, the ASAS-SN detected a supernova in NGC 1637 at ≈ 39–40 Mly. 🔭 ⚛️ 🧪

One team searched old archive images & found the star that exploded: the first published detection of a supernova progenitor candidate by #JWST.

Full paper here ➡️ iopscience.iop.org/article/10.3...

#universe 1/8

This composite image from New Horizons shows Jupiter and its moon Io during the 2007 flyby. Jupiter, in false-color infrared, displays swirling cloud bands with the Great Red Spot as a prominent bluish-white oval storm. Warmer lower clouds appear reddish, higher hazes blue, highlighting atmospheric dynamics. Io, in near-true color, is superimposed. Its night side reveals a bright red glowing lava eruption at Tvashtar volcano, with a 330-km-high blue-tinged plume rising above, lit by scattered sunlight. The montage contrasts Jupiter’s vast atmosphere with Io’s intense volcanic activity during the gravity-assist maneuver.

In Feb 2007, New Horizons passed Jupiter & its active moon Io. ⚛️

In this nice montage, Jupiter was captured in 3 bands of infrared light making the Great Red Spot look white.🧪

Io is digitally superposed in natural color, showing an ongoing eruption.🔭

➡️ apod.nasa.gov/apod/ap08010...

#science 1/3

The moon looks deep red on the right side and light red on the left side.

This morning, millions across parts of North America, Asia, New Zealand and Australia saw the moon turn red in a stunning total lunar #eclipse. Did you see the spectacular #BloodMoon? If you weren't one of the lucky spectators, enjoy this new gallery:
buff.ly/tMxqNaC

📸 Catherine Hyde, California.

This 2007 flyby served as a gravitational assist to accelerate the spacecraft toward Pluto, while at the same time enabling detailed observations of Jupiter and its moons.

Image Credit: NASA, Johns Hopkins U. APL, SWRI

2/3
Let's remember New Horizons spacecraft arrived at Pluto in 2015, and encountered Kuiper Belt object Arrokoth in 2019, the farthest flyby in history!

This composite image from New Horizons shows Jupiter and its moon Io during the 2007 flyby. Jupiter, in false-color infrared, displays swirling cloud bands with the Great Red Spot as a prominent bluish-white oval storm. Warmer lower clouds appear reddish, higher hazes blue, highlighting atmospheric dynamics. Io, in near-true color, is superimposed. Its night side reveals a bright red glowing lava eruption at Tvashtar volcano, with a 330-km-high blue-tinged plume rising above, lit by scattered sunlight. The montage contrasts Jupiter’s vast atmosphere with Io’s intense volcanic activity during the gravity-assist maneuver.

In Feb 2007, New Horizons passed Jupiter & its active moon Io. ⚛️

In this nice montage, Jupiter was captured in 3 bands of infrared light making the Great Red Spot look white.🧪

Io is digitally superposed in natural color, showing an ongoing eruption.🔭

➡️ apod.nasa.gov/apod/ap08010...

#science 1/3

"[Image description: At left, a field of space with a dozen white foreground stars and a number of small, yellow background galaxies. An unremarkable area at centre is outlined with a dashed circle surrounded by a white box. Lines extend from the box to a pullout at right containing faint, grainy white light surrounded by a circle labeled 'Candidate dark galaxy – diffuse emission.' Four white dots are circled in blue and labeled globular clusters.]" Source: the ESA press release linked in the thread.

🧵1/7
Just read about CDG-2, a candidate "almost dark" galaxy in the Perseus cluster, identified using #Hubble, #Euclid, and #Subaru. 🔭🧪⚛️

➡️ www.esa.int/Science_Expl...

It's really intriguing because it seems almost entirely dominated by #darkmatter (DM), with very few scattered stars.

#astronomy

Haha, "Gravitational Harassment" is such a perfect way to put it! It's one of those astronomy terms that sounds almost like it's from a courtroom drama, but it perfectly captures what happens in dense clusters.

...and whether it's lost material.
Fingers crossed for JWST or a big ground-based spectrograph to get those spectra soon – it would answer a lot of these open questions.
5/5

whittled down.
That's exactly why spectroscopy on the 4 GCs (and ideally on any faint diffuse component) would be huge – radial velocities would give us line-of-sight kinematics, let us estimate the enclosed mass, check if the GCs are truly bound, and start constraining the halo shape...
4/

though it's harder to strip DM than gas because it's collisionless and more centrally concentrated in many models.Right now there's no kinematic data to measure the current DM distribution or mass-loss history, so we can't tell if this is a "pristine" ultra-low-baryon system or one that's been
3/