Alastair Williams
@alastairwilliams.bsky.social
Space engineer, science writer, and author of The Quantum Cat
New post up, looking this week at how the sister-stars of the Pleiades are now scattered across the night sky.
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The Week in Space and Physics: The Lost Sisters of the Pleiades
On the stars of the Pleiades, a superflare from a black hole, the second flight of New Glenn, and the aurora.
www.thequantumcat.space
November 26, 2025 at 2:37 PM
New post up, looking this week at how the sister-stars of the Pleiades are now scattered across the night sky.
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This is 1) a stupid idea and 2) something that will never work economically anyway.
"The beam reflected by these satellites is very intense, four times brighter than the full Moon."
Scientists Oppose Huge Array of Mirrors in Space That Shines Nighttime Sunlight on Wealthy Customers
The astronomical community is horrified at plans made by a for-profit company to flood the night sky with sunlight.
trib.al
November 26, 2025 at 10:56 AM
This is 1) a stupid idea and 2) something that will never work economically anyway.
Reposted by Alastair Williams
This is an incredible image of comet 3I/ATLAS, taken by Satoru Murata ICQ Comet Observations group on 16 November 2025 from western New Mexico.
Structure within the major dust tail from the comet is clearly visible, together with two smaller jets trailing the nucleus and maybe even an anti-tail.
Structure within the major dust tail from the comet is clearly visible, together with two smaller jets trailing the nucleus and maybe even an anti-tail.
November 24, 2025 at 11:50 PM
This is an incredible image of comet 3I/ATLAS, taken by Satoru Murata ICQ Comet Observations group on 16 November 2025 from western New Mexico.
Structure within the major dust tail from the comet is clearly visible, together with two smaller jets trailing the nucleus and maybe even an anti-tail.
Structure within the major dust tail from the comet is clearly visible, together with two smaller jets trailing the nucleus and maybe even an anti-tail.
Reposted by Alastair Williams
I am not sure this work is better than my bot's, but I did try to integrate all NIRCam data. I had to compromise the resolution, it was too much for my laptop to handle in full scale.
JWST 🔭: NASA, ESA, CSA, STScI.
JWST 🔭: NASA, ESA, CSA, STScI.
November 24, 2025 at 8:02 AM
I am not sure this work is better than my bot's, but I did try to integrate all NIRCam data. I had to compromise the resolution, it was too much for my laptop to handle in full scale.
JWST 🔭: NASA, ESA, CSA, STScI.
JWST 🔭: NASA, ESA, CSA, STScI.
The Biggest Solar Flare of 2025
A flare hits Earth. But when will a really big one come?
www.thequantumcat.space
November 24, 2025 at 1:10 PM
Do people really want to read easily understood descriptions of recent papers in astronomy or physics? Astronomers probably don’t, or if they do, the audience of potential astronomers is so small and so poorly paid that they don’t make a viable audience.
November 11, 2025 at 1:52 PM
Do people really want to read easily understood descriptions of recent papers in astronomy or physics? Astronomers probably don’t, or if they do, the audience of potential astronomers is so small and so poorly paid that they don’t make a viable audience.
In today's post I look at NASA's struggles to get back to the Moon, the perihelion of interstellar comet 3I/Atlas, and the end of our last probe around Venus (we really should send another one!)
🔭🧪 #astronomy #space #nasa
🔭🧪 #astronomy #space #nasa
The Week in Space and Physics: The Next Footprints on the Moon
On NASA's effort to get back to the Moon, the future of space stations, interstellar comets, and the last satellite around Venus.
www.thequantumcat.space
November 5, 2025 at 2:49 PM
In today's post I look at NASA's struggles to get back to the Moon, the perihelion of interstellar comet 3I/Atlas, and the end of our last probe around Venus (we really should send another one!)
🔭🧪 #astronomy #space #nasa
🔭🧪 #astronomy #space #nasa
Mars may have once hosted life. In 2024, Perseverance found minerals that, on Earth, would be clear biosignatures. A big discovery—but not yet proof of life beyond Earth. Plus: TRAPPIST-1e, a folly of a new Moon race, and the interstellar comet 3I/ATLAS.
#space #astronomy #science
#space #astronomy #science
The Week in Space and Physics: Was There Life on Mars?
On a discovery on Mars, the folly of a new Moon race, Trappist 1e, and the approach of an interstellar comet
www.thequantumcat.space
September 16, 2025 at 8:25 PM
Mars may have once hosted life. In 2024, Perseverance found minerals that, on Earth, would be clear biosignatures. A big discovery—but not yet proof of life beyond Earth. Plus: TRAPPIST-1e, a folly of a new Moon race, and the interstellar comet 3I/ATLAS.
#space #astronomy #science
#space #astronomy #science
This is really not a surprise - the details of the project always made it impracticable. Fun idea, but not a realistic way to reach the stars any time soon.
Great writeup by Sarah Scoles @sarahscoles.bsky.social on the apparent demise of Breakthrough Starshot
An abandoned plan to visit another star highlights the perils of billionaire-funded science
September 16, 2025 at 8:21 PM
This is really not a surprise - the details of the project always made it impracticable. Fun idea, but not a realistic way to reach the stars any time soon.
In this incredible image, the Earth eclipses the Sun. Viewed by the returning astronauts of Apollo 12, and credit goes to them and to NASA.
#space #art #historyofastronomy
#space #art #historyofastronomy
July 23, 2025 at 4:06 PM
In this incredible image, the Earth eclipses the Sun. Viewed by the returning astronauts of Apollo 12, and credit goes to them and to NASA.
#space #art #historyofastronomy
#space #art #historyofastronomy
What is it that lies beyond the edge of the solar system? What fills the space between the stars? These are questions we are beginning to answer - and, for the first time, we have probes that are venturing out into this untouched terrain.
#science #space
#science #space
What Lies Beyond: Exploring Interstellar Space
Forget reaching the stars, first we need to explore the space between them
open.substack.com
July 22, 2025 at 3:35 PM
Two years ago I published a list of serious and free physics resources. The idea was to create a guide for those studying physics, either alone or as part of a course.
I'm now working on an update - and, if you know of free and good physics resources like those here, I'd love to hear of them.
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I'm now working on an update - and, if you know of free and good physics resources like those here, I'd love to hear of them.
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How to Learn Physics for Free
A guide for the curious
www.thequantumcat.space
July 21, 2025 at 3:57 PM
Two years ago I published a list of serious and free physics resources. The idea was to create a guide for those studying physics, either alone or as part of a course.
I'm now working on an update - and, if you know of free and good physics resources like those here, I'd love to hear of them.
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I'm now working on an update - and, if you know of free and good physics resources like those here, I'd love to hear of them.
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A concept from 1969 of a space station. It was to be made of old Apollo stages, and to make sure the astronauts living there did not suffer from endless weightlessness, the station was supposed to constantly spin as it orbited the Earth.
Credit, of course, to NASA.
#space #art #NASA
Credit, of course, to NASA.
#space #art #NASA
July 18, 2025 at 3:57 PM
Reposted by Alastair Williams
Via #TimesNowNews - Felix Baumgartner, the Austrian daredevil best known for his 2012 supersonic skydive from the stratosphere, has died in a paragliding accident in Italy. He was 56 years old. www.timesnownews.com/world/who-wa...
Who Was Felix Baumgartner? Skydiver Who Jumped From Space Dies In Paragliding Accident At 56
Felix Baumgartner, the Austrian daredevil best known for his 2012 supersonic skydive from the stratosphere, has died in a paragliding accident in Italy. He was 56 years old. According to reports, Baum...
www.timesnownews.com
July 17, 2025 at 7:20 PM
Via #TimesNowNews - Felix Baumgartner, the Austrian daredevil best known for his 2012 supersonic skydive from the stratosphere, has died in a paragliding accident in Italy. He was 56 years old. www.timesnownews.com/world/who-wa...
Dark energy is pretty cool right? Or maybe it isn't. To be honest we don't know all that much about it.
But it sure seems like it is going to play a big role in deciding the fate of the universe. And that makes it interesting enough for an article on the stuff. Check it out here!
But it sure seems like it is going to play a big role in deciding the fate of the universe. And that makes it interesting enough for an article on the stuff. Check it out here!
What Dark Energy Means For The End of Time
On the mysteries of dark energy and the fate of the universe
www.thequantumcat.space
July 17, 2025 at 7:48 PM
Dark energy is pretty cool right? Or maybe it isn't. To be honest we don't know all that much about it.
But it sure seems like it is going to play a big role in deciding the fate of the universe. And that makes it interesting enough for an article on the stuff. Check it out here!
But it sure seems like it is going to play a big role in deciding the fate of the universe. And that makes it interesting enough for an article on the stuff. Check it out here!
My newsletter this week: on interstellar comets, how New Horizons is reviving the ancient art of celestial navigation, the top quark and toponium, and a study of the lost rivers of Mars.
Oh, and some gorgeous celestial art thanks to the brilliant James Webb telescope.
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Oh, and some gorgeous celestial art thanks to the brilliant James Webb telescope.
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The Week in Space and Physics: The Third Interstellar Comet
On interstellar comets, navigating to the stars, the social lives of quarks, and the lost rivers of Mars
www.thequantumcat.space
July 16, 2025 at 8:31 PM
My newsletter this week: on interstellar comets, how New Horizons is reviving the ancient art of celestial navigation, the top quark and toponium, and a study of the lost rivers of Mars.
Oh, and some gorgeous celestial art thanks to the brilliant James Webb telescope.
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Oh, and some gorgeous celestial art thanks to the brilliant James Webb telescope.
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It's going to be an incredible moment if or when we snap a picture of an interstellar comet from the surface of another world.
The interstellar comet 3I-Atlas trajectory. We'll take a look with the cameras on ExoMars TGO!!
🧪🔭 #planetsci
🧪🔭 #planetsci
July 16, 2025 at 8:16 PM
It's going to be an incredible moment if or when we snap a picture of an interstellar comet from the surface of another world.
Reposted by Alastair Williams
Our Ariel mission will take us from 'discovering' towards 'studying and understanding' exoplanets.
The mission will survey about 1000 exoplanets, ranging from rocky planets to gas giants, to better understand the link between exoplanets and their parent stars 👉 www.esa.int/Science_Expl...
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The mission will survey about 1000 exoplanets, ranging from rocky planets to gas giants, to better understand the link between exoplanets and their parent stars 👉 www.esa.int/Science_Expl...
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July 4, 2025 at 7:00 AM
Our Ariel mission will take us from 'discovering' towards 'studying and understanding' exoplanets.
The mission will survey about 1000 exoplanets, ranging from rocky planets to gas giants, to better understand the link between exoplanets and their parent stars 👉 www.esa.int/Science_Expl...
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The mission will survey about 1000 exoplanets, ranging from rocky planets to gas giants, to better understand the link between exoplanets and their parent stars 👉 www.esa.int/Science_Expl...
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In ten years time, when Americans are asking what went wrong, the last six months will be the answer.
July 4, 2025 at 10:55 AM
In ten years time, when Americans are asking what went wrong, the last six months will be the answer.
It certainly feels like America is on the verge of a mistake that will be felt decades into the future.
A hugely important point: this is the most inexperienced natsec team in history and they're loyalists who will not stop Trump's final decision. We love to complain about elites, who can make terrible mistakes. But elites, including advisers, are a *vital* source of constraint on elected leaders. 1/
Hard to overstate the degree to which there appears to be literally no one in the president's current circle who has any experience, even at a low level, managing ANY kind of national security crisis or even situation. talkingpointsmemo.com/edblog/thoug...
June 17, 2025 at 10:40 PM
It certainly feels like America is on the verge of a mistake that will be felt decades into the future.
In 2012 the NRO gave NASA two 2.4m diameter mirrors. One is part of the Nancy Grace Roman Telescope. What happened to the other? Is it forgotten in some warehouse somewhere, awaiting the funds to build another Hubble? Or did something else happen to it?
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June 9, 2025 at 8:42 PM
In 2012 the NRO gave NASA two 2.4m diameter mirrors. One is part of the Nancy Grace Roman Telescope. What happened to the other? Is it forgotten in some warehouse somewhere, awaiting the funds to build another Hubble? Or did something else happen to it?
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Reposted by Alastair Williams
Don’t get me wrong, I think it’s hilarious, but my laughter would be less nervous if one of the guys didn’t have control of the biggest military in the world and the other one didn’t have rockets, a satellite network, and thousands of tactical-ready pickup trucks just sitting around.
June 5, 2025 at 9:55 PM
Don’t get me wrong, I think it’s hilarious, but my laughter would be less nervous if one of the guys didn’t have control of the biggest military in the world and the other one didn’t have rockets, a satellite network, and thousands of tactical-ready pickup trucks just sitting around.
Reposted by Alastair Williams
Waxing Crescent Moon. 2048UT 30 May 2025. 🔭 🧪 🎨 #astrophotography #SciArt #photography #StormHour #ThePhotoHour
May 30, 2025 at 9:27 PM
Waxing Crescent Moon. 2048UT 30 May 2025. 🔭 🧪 🎨 #astrophotography #SciArt #photography #StormHour #ThePhotoHour