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drnereide.bsky.social
Nereide
@drnereide.bsky.social
5.1K followers 74 following 3.4K posts
Physicist interested in Astrophysics and Particle Physics| Research in Math and Science Edu| Math and Science Writer| Teacher and Teacher Trainer| WomenInSTEM

My science blog: https://www.tutto-scienze.org/

More about me: https://x.com/settings/bio
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drnereide.bsky.social
Nereide @drnereide.bsky.social · 1d
🧵
This pic from Mike Selby and Mark Hanson is as pretty as a painting, but it's absolutely real.

It shows a blue reflection nebula known as NGC 2626, which lies some 3200 light-years from Earth along the Vela Molecular Ridge.

➡️ apod.nasa.gov/apod/ap23020...

🔭 🧪 #science

1/3
Admire this stunning shot from a telescope showing a bright patch of blue glow right in the middle—that's NGC 2626, lit up by a young star buried inside it. Dark dusty streaks cut across like veins, hiding parts behind them. Nearby, you get these soft red areas where hydrogen gas is shining from a big zone called RCW 27. All of it sits in a busy part of space full of clouds where new stars are born, way out in the Vela area, with little stars twinkling far off in the dark.
Reposted by Nereide
davidho.bsky.social
If a king is going to drag us into war, he should be on the frontline fighting.
January 3, 2026 at 11:17 PM
Reposted by Nereide
drnereide.bsky.social
🧵
This pic from Mike Selby and Mark Hanson is as pretty as a painting, but it's absolutely real.

It shows a blue reflection nebula known as NGC 2626, which lies some 3200 light-years from Earth along the Vela Molecular Ridge.

➡️ apod.nasa.gov/apod/ap23020...

🔭 🧪 #science

1/3
Admire this stunning shot from a telescope showing a bright patch of blue glow right in the middle—that's NGC 2626, lit up by a young star buried inside it. Dark dusty streaks cut across like veins, hiding parts behind them. Nearby, you get these soft red areas where hydrogen gas is shining from a big zone called RCW 27. All of it sits in a busy part of space full of clouds where new stars are born, way out in the Vela area, with little stars twinkling far off in the dark.
January 3, 2026 at 12:14 AM
drnereide.bsky.social
🧵
This pic from Mike Selby and Mark Hanson is as pretty as a painting, but it's absolutely real.

It shows a blue reflection nebula known as NGC 2626, which lies some 3200 light-years from Earth along the Vela Molecular Ridge.

➡️ apod.nasa.gov/apod/ap23020...

🔭 🧪 #science

1/3
Admire this stunning shot from a telescope showing a bright patch of blue glow right in the middle—that's NGC 2626, lit up by a young star buried inside it. Dark dusty streaks cut across like veins, hiding parts behind them. Nearby, you get these soft red areas where hydrogen gas is shining from a big zone called RCW 27. All of it sits in a busy part of space full of clouds where new stars are born, way out in the Vela area, with little stars twinkling far off in the dark.
January 3, 2026 at 12:14 AM
Reposted by Nereide
drnereide.bsky.social
Fireworks over, then this beauty: Jupiter's bands, the fading Great Red Spot, and little Europa as a distant dot.

Stunning detail—this is a wonderful start to 2026.

🔭 🧪 #science #planetsci #HappyNewYear
stim3on.bsky.social Simeon Schmauß @stim3on.bsky.social · 2d
Last night I set up my telescope so we could all watch the planets while waiting for the new year to arrive.

After the fireworks had subsided, I attached my camera and captured my first astrophoto of the year featuring Jupiter and its moon Europa. #astrophotography

Happy New Year everyone!
The planet Jupiter with its many bands of clouds spanning around it. The Great Red Spot is visible on the right side of the planet, about to rotate out of view. To the left of the planet is a bright dot, which is the moon Europa.
January 2, 2026 at 12:00 PM
drnereide.bsky.social
Fireworks over, then this beauty: Jupiter's bands, the fading Great Red Spot, and little Europa as a distant dot.

Stunning detail—this is a wonderful start to 2026.

🔭 🧪 #science #planetsci #HappyNewYear
stim3on.bsky.social Simeon Schmauß @stim3on.bsky.social · 2d
Last night I set up my telescope so we could all watch the planets while waiting for the new year to arrive.

After the fireworks had subsided, I attached my camera and captured my first astrophoto of the year featuring Jupiter and its moon Europa. #astrophotography

Happy New Year everyone!
The planet Jupiter with its many bands of clouds spanning around it. The Great Red Spot is visible on the right side of the planet, about to rotate out of view. To the left of the planet is a bright dot, which is the moon Europa.
January 2, 2026 at 12:00 PM
Reposted by Nereide
drnereide.bsky.social
“The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself.”
~Carl Sagan~

Every #NewYear reminds us that we are part of the cosmic cycle of birth and transformation.

#HappyNewYear everybody

🔭 🧪 #universe 1/2
A vibrant, face-on view of the Fireworks Galaxy (NGC 6946), a beautiful spiral galaxy located in the constellation Cepheus.The image shows a colorful cosmic portrait with a yellowish core dominated by older stars, transitioning to loose and fragmented spiral arms featuring bright blue clusters of young stars and vivid reddish-pink star-forming regions glowing like bursts of fireworks against the dark backdrop of star-studded space.
December 31, 2025 at 4:43 PM
Reposted by Nereide
johncarlosbaez.bsky.social
Happy New Year!

Last year was so bad that I decided that what people need from me most is not more warnings, but a bit of happiness.

Like this design for a stained glass window by @gregegansf.bsky.social, based on a 4-dimensional lattice (see alt text).

You could build it with a few parts!
A quasiperiodic design built from two shapes: isosceles triangles with 36° - 72° - 72° angles, and isosceles triangles with 36° - 36° - 108° angles. The latter look transparent and you can see a blue sky behind them. The former are pink. These were created by Greg Egan's applet https://www.gregegan.net/APPLETS/31/31.html setting n = 4. This creates tilings are known as “Tübingen triangular tilings”, based on the Aₙ lattice. The n-dimensional lattice Aₙ consists of (n+1)-tuples of integers that sum to zero; it's a lattice in the hyperplane consisting of (n+1)-tuples of real numbers that sum to zero. Taking n = 4 we get the A₄ lattice. Spheres centered at points of this lattice give the densest packing of spheres in 4-dimensional space! For more details see: https://www.gregegan.net/APPLETS/12/deBruijnNotes.html
January 1, 2026 at 11:57 AM
drnereide.bsky.social
“The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself.”
~Carl Sagan~

Every #NewYear reminds us that we are part of the cosmic cycle of birth and transformation.

#HappyNewYear everybody

🔭 🧪 #universe 1/2
A vibrant, face-on view of the Fireworks Galaxy (NGC 6946), a beautiful spiral galaxy located in the constellation Cepheus.The image shows a colorful cosmic portrait with a yellowish core dominated by older stars, transitioning to loose and fragmented spiral arms featuring bright blue clusters of young stars and vivid reddish-pink star-forming regions glowing like bursts of fireworks against the dark backdrop of star-studded space.
December 31, 2025 at 4:43 PM
Reposted by Nereide
drnereide.bsky.social
🧵
This JWST's view of the Red Spider Nebula (NGC 6537) is spectacular!

It's about a planetary nebula i.e. the remnants of a Sun-like star shedding its outer layers, ionizing the ejected gas.

Webb's NIRCam reveals hot dust & stunning details amid stars.

➡️ esawebb.org/images/potm2...

🔭 🧪 1/6
"A large planetary nebula. The nebula’s central star is hidden by a blotchy pinkish cloud of dust. A strong red light radiates from this area, illuminating the nearby dust. Two large loops extend diagonally away from the centre, formed of thin ridges of molecular gas, here coloured blue. They stretch out to the corners of the view. A huge number of bright, whitish stars cover the background, also easily visible through the thin dust layers."
December 30, 2025 at 6:17 PM
Reposted by Nereide
drnereide.bsky.social
🧵
The Boomerang Nebula, with a temperature of 1 degree Kelvin, is the coldest natural place known in the Universe, colder than the cosmic microwave background (about 2.73 Kelvin), which is the faint afterglow of the Big Bang.

➡️ public.nrao.edu/news/alma-re...

🔭 🧪 #cosmology #science
The image of the Boomerang Nebula, observed with the ALMA telescope, reveals a complex and ghostly shape, combining unique visual details with a more intricate structure than previous observations. The nebula has a shape that, in its inner regions, resembles an hourglass or a double lobe, with two symmetrical areas extending in opposite directions from a narrow center. These inner regions are dominated by shades of hazy blue, giving them a cool and ethereal appearance, due to the starlight reflecting off the dust grains. Visually superimposed on the central part of this hourglass is a ghostly shape, described as "eerily ghost-like", which manifests itself in a vivid bright orange-red. This central, apparition-like structure contrasts sharply with the surrounding blue, creating a striking visual effect, as if a bright, hot core is pulsating inside a cooler shell. The ALMA observations, however, reveal that the classic double-lobe shape, previously observed by the #Hubble Space Telescope, is only part of the story. The outer regions of the nebula expand into a larger shape, with less sharp edges and a more uniform distribution of gaseous material. These outer areas gradually fade into darker, more transparent hues, merging with the black background of space. A dense band of dust, visible as a duller, darker area, surrounds the central star, contributing to the hourglass effect in visible light: the starlight filters through only in two opposite directions, accentuating the contrast between the illuminated and shadowed regions. Overall, the image evokes a sense of dynamism, with the orange-red ghostly shape at the center appearing to float within the blue hourglass structure, while the nebula expands outward into a large gaseous halo, creating a contrast between the sharpness of the nucleus and the softness of the outer edges.
June 17, 2025 at 2:11 PM
Reposted by Nereide
drnereide.bsky.social
#OTD in 1906, the pioneering physicist Maria Goeppert-Mayer was born.

She entered history as the nuclear shell model theorist &
as the 2nd woman to win the Nobel Prize in Physics, after Marie Curie.

M. G. Mayer and J. H. D. Jensen shared one half of the Nobel Prize

⚛️ 🧪 #WomenInStem #HistSci
1/2
Black and white portrait of Maria Goeppert- Mayer, sitting. She is wearing a patterned dress and has short hair, her gaze is directed upward. Behind her, and in the background, there is a black board full of graphic symbols.
June 28, 2025 at 12:33 PM
drnereide.bsky.social
🧵
This JWST's view of the Red Spider Nebula (NGC 6537) is spectacular!

It's about a planetary nebula i.e. the remnants of a Sun-like star shedding its outer layers, ionizing the ejected gas.

Webb's NIRCam reveals hot dust & stunning details amid stars.

➡️ esawebb.org/images/potm2...

🔭 🧪 1/6
"A large planetary nebula. The nebula’s central star is hidden by a blotchy pinkish cloud of dust. A strong red light radiates from this area, illuminating the nearby dust. Two large loops extend diagonally away from the centre, formed of thin ridges of molecular gas, here coloured blue. They stretch out to the corners of the view. A huge number of bright, whitish stars cover the background, also easily visible through the thin dust layers."
December 30, 2025 at 6:17 PM
Reposted by Nereide
coreyspowell.bsky.social
It's happening! ESA & JAXA are teaming up to visit Apophis, the 400-meter (1300-foot) asteroid that will skim close by Earth in April, 2029.

The RAMSES mission will study this potentially hazardous object & watch how Earth's gravity reshapes it as it passes. 🧪🔭

cosmos.isas.jaxa.jp/look-up-esa-...
Artist’s impression of ESA’s Rapid Apophis Mission for Space Safety, Ramses as it flies past Apophis in 2029.
December 29, 2025 at 6:55 PM
Reposted by Nereide
drnereide.bsky.social
🧵
1/
For those who missed it, this recent image from Webb's NIRCam features a part of the Leo P dwarf galaxy (the blue stars at lower right) along with countless other galaxies in the background.

Reference➡️ esawebb.org/images/LeoP/

A team's research, done

🔭 🧪 #extragalactic #Webb #JWST
This image from Webb's NIRCam features a portion of the Leo P dwarf galaxy (the blue stars at lower right) along with countless other galaxies in the background.
January 22, 2025 at 12:47 PM
Reposted by Nereide
drnereide.bsky.social
🧵
Ever seen a #rainbow that's just shades of red?

It's about a monochrome or red rainbow—a rare variation of the more commonly seen multicolored one.

An optical & meteorological phenomenon really mesmerizing that happens mostly at sunrise or sunset.

Image by Astronautilus

🔭 🧪 ⚛️ #sciart

1/6
A striking photograph of a rare monochrome #rainbow arching across a dramatic dusk #sky during a thunderstorm. The entire bow glows in deep crimson red tones. No other colors are visible, creating an intense, almost ethereal effect. In the foreground, a suburban landscape with a house and dark trees. Captured on July 6, 1980, in a Minneapolis suburb by photographer Rod Jones (Astronautilus). CC BY 2.0.
December 28, 2025 at 8:18 PM
drnereide.bsky.social
🧵
Ever seen a #rainbow that's just shades of red?

It's about a monochrome or red rainbow—a rare variation of the more commonly seen multicolored one.

An optical & meteorological phenomenon really mesmerizing that happens mostly at sunrise or sunset.

Image by Astronautilus

🔭 🧪 ⚛️ #sciart

1/6
A striking photograph of a rare monochrome #rainbow arching across a dramatic dusk #sky during a thunderstorm. The entire bow glows in deep crimson red tones. No other colors are visible, creating an intense, almost ethereal effect. In the foreground, a suburban landscape with a house and dark trees. Captured on July 6, 1980, in a Minneapolis suburb by photographer Rod Jones (Astronautilus). CC BY 2.0.
December 28, 2025 at 8:18 PM
Reposted by Nereide
drnereide.bsky.social
🧵
This cosmic wonder is reminiscent of a Christmas scene!

The image depicts NGC 2264, an energetic star-forming region, with its brilliant red hues due to molecular hydrogen.

Located about 2,700 light-years away in Monoceros, ...⤵️

➡️ apod.nasa.gov/apod/ap20122...

🔭 🧪 #science #galactic

1/4
Colorful pic of NGC 2264 in Monoceros constellation. Bright red hydrogen clouds glow from energy of young stars, with dark dust trails running through them. Left side: Fox Fur Nebula as tangled dark clumps. Center: variable star S Monocerotis in soft blue haze. Right edge: dark Cone Nebula as a pointed pillar. Brighter stars outline a sideways Christmas Tree – tip at the Cone, base near S Monocerotis. The view covers a sky area about three full moons wide against deep black space.
December 27, 2025 at 6:53 PM
drnereide.bsky.social
🧵
This cosmic wonder is reminiscent of a Christmas scene!

The image depicts NGC 2264, an energetic star-forming region, with its brilliant red hues due to molecular hydrogen.

Located about 2,700 light-years away in Monoceros, ...⤵️

➡️ apod.nasa.gov/apod/ap20122...

🔭 🧪 #science #galactic

1/4
Colorful pic of NGC 2264 in Monoceros constellation. Bright red hydrogen clouds glow from energy of young stars, with dark dust trails running through them. Left side: Fox Fur Nebula as tangled dark clumps. Center: variable star S Monocerotis in soft blue haze. Right edge: dark Cone Nebula as a pointed pillar. Brighter stars outline a sideways Christmas Tree – tip at the Cone, base near S Monocerotis. The view covers a sky area about three full moons wide against deep black space.
December 27, 2025 at 6:53 PM
Reposted by Nereide
drnereide.bsky.social
Did you know that a #rainbow makes a full 360 degree circle?

In this photo, an entire rainbow was captured over Cottesloe Beach near Perth by a helicopter.

From the ground, typically, only the top portion...⤵️

➡️ apod.nasa.gov/apod/ap14093...

🔭 🧪 ⚛️ #science #naturephotography #sciart

1/4
Aerial helicopter photo showing a complete circular rainbow arching over a coastal Australian landscape. The bright primary rainbow displays full spectrum colors in a perfect ring, with a dimmer secondary one outside it featuring reversed hues. Below lies sandy shoreline, crashing waves in teal ocean, green fields, urban areas, and a stormy sky lit by setting sun.
December 26, 2025 at 9:54 PM
Reposted by Nereide
johncarlosbaez.bsky.social
New result: you can build a universal computer using a single billiard ball on a carefully crafted table!

More precisely: you can create a computer that can run any program, using just a single point moving frictionlessly in a region of the plane and bouncing off the walls elastically.

(1/n)
Classical billiards can compute Eva Miranda, Isaac Ramos We show that two-dimensional billiard systems are Turing complete by encoding their dynamics within the framework of Topological Kleene Field Theory. Billiards serve as idealized models of particle motion with elastic reflections and arise naturally as limits of smooth Hamiltonian systems under steep confining potentials. Our results establish the existence of undecidable trajectories in physically natural billiard-type models, including billiard-type models arising in hard-sphere gases and in collision-chain limits of celestial mechanics. Significance statement. Billiards are a textbook model of deterministic motion: a particle moves freely and reflects specularly from rigid walls. We show that, even in two dimensions, billiard trajectories can simulate arbitrary Turing machines. This universality implies a sharp limit on prediction: there is no general algorithm that can decide basic questions such as whether a trajectory is periodic. Because billiards also arise as limits of smooth Hamiltonian systems with increasingly steep confining potentials, these algorithmic barriers are not confined to idealized hard-wall models. Our results place undecidability, alongside chaos, as a fundamental obstruction to long-term prediction even in low-dimensional classical dynamics. From here: https://arxiv.org/abs/2512.19156
December 23, 2025 at 10:21 AM
Reposted by Nereide
johncarlosbaez.bsky.social
Ever wonder about the math hiding in music? There's a lot of it, and it's really fun! Here's a first take on some of it.

(When you're done, you'll know why musicians have special names for the numbers 81/80 and 128/125.)

johncarlosbaez.wordpress.com/2025/12/26/t...
The Mathematics of Tuning Systems
I’m giving a talk on the math of tuning systems at Claremont McKenna College on January 30th at 11 am. If you’re around, please come! You can read my slides here: • The mathematics…
johncarlosbaez.wordpress.com
December 26, 2025 at 3:18 PM
drnereide.bsky.social
Did you know that a #rainbow makes a full 360 degree circle?

In this photo, an entire rainbow was captured over Cottesloe Beach near Perth by a helicopter.

From the ground, typically, only the top portion...⤵️

➡️ apod.nasa.gov/apod/ap14093...

🔭 🧪 ⚛️ #science #naturephotography #sciart

1/4
Aerial helicopter photo showing a complete circular rainbow arching over a coastal Australian landscape. The bright primary rainbow displays full spectrum colors in a perfect ring, with a dimmer secondary one outside it featuring reversed hues. Below lies sandy shoreline, crashing waves in teal ocean, green fields, urban areas, and a stormy sky lit by setting sun.
December 26, 2025 at 9:54 PM
Reposted by Nereide
drnereide.bsky.social
"Christmas is not in tinsel and lights and outward show.

The secret lies in an inner glow.

It's lighting a fire inside the heart.
[...]
It's glorious dream in the soul of man."

~ W. A. Peterson in 'The Art of Living'

#MerryChristmas everybody✨🎄🎅

➡️ eso.org/public/image...

🔭 🧪 #Universe
#ESO pic of the NGC 2264 region that includes the #Christmas Tree Cluster. You've got these young stars shining like bright blue ornaments on a cosmic tree made of reddish and greenish gas clouds. Down there's the dark Cone #Nebula sticking out like a shadowy cone. They built this color image using four filters – B, V, R, and H-alpha – with the Wide Field Imager at ESO's La Silla Observatory up in the Chilean Andes.
December 24, 2025 at 3:56 PM
drnereide.bsky.social
This #Christmas🎄, instead of leaving Tiny Tim locked in a potentially dangerous box, we choose the more humane path: carefully removing every risk & helping him emerge safe & sound.

A gentle reminder that true science goes hand in hand with compassion💜, & that kindness🌺 always lights up the world✨
astrokatie.com Katie Mack @astrokatie.com · 10d
[breathing a sigh of relief as I carefully remove the poison, hammer, Geiger counter, and radioactive source before helping Tiny Tim out of the box]
December 25, 2025 at 9:11 AM
drnereide.bsky.social
Too ambitious? Absolutely! 🙂

I suggest a compromise: close one tab per day in 2026.
By NYE you’ll either be a legend… or have opened 2000 more to replace them.

Good luck — may your tabs be ever in your favor!

#NYE2026
drspacejunk.bsky.social Dr Space Junk (Alice Gorman) @drspacejunk.bsky.social · 11d
My New Year's resolution: to tidy up my open browser tabs. What do you think? Too ambitious? #NYE2026
December 24, 2025 at 7:52 PM