Katie Mack
@astrokatie.com
Cosmologist, pilot, author, connoisseur of cosmic catastrophes. TEDFellow, CIFAR Azrieli Global Scholar. Domain verified through my personal astrokatie.com website. She/her. Dr.
Personal account; not speaking for employer or anyone else.
Personal account; not speaking for employer or anyone else.
Pinned
Katie Mack
@astrokatie.com
· Nov 30
The End of Everything — KATIE MACK, ASTROPHYSICIST
Information about "The End of Everything (Astrophysically Speaking)" by Katie Mack
www.astrokatie.com
This holiday season, why not give the gift of ultimate cosmic destruction?? 💥🌌
www.astrokatie.com/book
Kirkus Reviews calls it “a delightfully unsettling narrative”! @leebillings.bsky.social raves about my “infectious enthusiasm for communicating the finer points of cosmological doom”!
www.astrokatie.com/book
Kirkus Reviews calls it “a delightfully unsettling narrative”! @leebillings.bsky.social raves about my “infectious enthusiasm for communicating the finer points of cosmological doom”!
GM: Charisma check.
Mamdani: [rolls natural 20]
GM: that’s a d6 how did you
Mamdani: [direct to camera] Did you know you can check out board games at your local public library? 😊
Mamdani: [rolls natural 20]
GM: that’s a d6 how did you
Mamdani: [direct to camera] Did you know you can check out board games at your local public library? 😊
February 7, 2026 at 5:01 AM
GM: Charisma check.
Mamdani: [rolls natural 20]
GM: that’s a d6 how did you
Mamdani: [direct to camera] Did you know you can check out board games at your local public library? 😊
Mamdani: [rolls natural 20]
GM: that’s a d6 how did you
Mamdani: [direct to camera] Did you know you can check out board games at your local public library? 😊
This galaxy is VERY tiny—much much smaller than our own Milky Way—& incredibly distant. But we can see it AND distinguish its shape!
How?
The light we see from it is from SO LONG AGO that the Universe was MUCH smaller at the time: we see it as it was when it was close enough to us to look big!! 🤯
How?
The light we see from it is from SO LONG AGO that the Universe was MUCH smaller at the time: we see it as it was when it was close enough to us to look big!! 🤯
This is what the most distant confirmed galaxy looks like. The light we're receiving was emitted when the Universe was ~15x smaller in linear size than today, and right now it's ~30 billion light-years away from us. The light was emitted when the Universe was <300 million years old. Pretty amazing!
News from the edge of the visible universe:
JWST has confirmed this galaxy, MoM-z14, as the most distant one yet studied. We're seeing it as it was 13.5 billion years ago, 98% of the way back to the beginning of time.
(MoM stands for "miracle or mirage.") 🧪🔭
science.nasa.gov/missions/web...
JWST has confirmed this galaxy, MoM-z14, as the most distant one yet studied. We're seeing it as it was 13.5 billion years ago, 98% of the way back to the beginning of time.
(MoM stands for "miracle or mirage.") 🧪🔭
science.nasa.gov/missions/web...
February 7, 2026 at 2:28 AM
This galaxy is VERY tiny—much much smaller than our own Milky Way—& incredibly distant. But we can see it AND distinguish its shape!
How?
The light we see from it is from SO LONG AGO that the Universe was MUCH smaller at the time: we see it as it was when it was close enough to us to look big!! 🤯
How?
The light we see from it is from SO LONG AGO that the Universe was MUCH smaller at the time: we see it as it was when it was close enough to us to look big!! 🤯
Reposted by Katie Mack
Documents show RFK Jr lied to Congress about his agenda in Samoa—he did indeed go to spread anti-scientific doubts about vaccines. He was ultimately successful in getting an outbreak going there that killed 83 people, mostly babies and young children.
RFK Jr said during his Senate confirmation hearings that his trip to Samoa in 2019 ahead of a devastating measles outbreak had “nothing to do with vaccines." Documents obtained by @us.theguardian.com and @apnews.com undermine that testimony. Details here, by me and @aliswenson.bsky.social ⬇️
Newly revealed emails undermine RFK Jr testimony about 2019 Samoa trip ahead of measles outbreak
Kennedy later said the purpose of his trip had nothing to do with vaccines. US embassy and UN staff at the time said otherwise, emails show
www.theguardian.com
February 6, 2026 at 2:17 PM
Documents show RFK Jr lied to Congress about his agenda in Samoa—he did indeed go to spread anti-scientific doubts about vaccines. He was ultimately successful in getting an outbreak going there that killed 83 people, mostly babies and young children.
Reposted by Katie Mack
Important paper. Schools are high-risk environments for respiratory disease transmission MAINLY because classrooms are underventilated. This problem has a workable solution - it just needs political will. Air quality is as important as water quality for public health. MT @martinmckee.bsky.social
Our paper modelling transmission risk in schools is published in Nature Communications. **The relative contribution of close-proximity contacts, shared classroom exposure and indoor air quality to respiratory virus transmission in schools** doi.org/10.1038/s414...
February 5, 2026 at 10:59 PM
Important paper. Schools are high-risk environments for respiratory disease transmission MAINLY because classrooms are underventilated. This problem has a workable solution - it just needs political will. Air quality is as important as water quality for public health. MT @martinmckee.bsky.social
Reposted by Katie Mack
From NOAA Satellites:
The arctic blast that put much of Florida into a deep freeze also created these mesmerizing cloud streets caught by bsky.app/profile/noaa.gov 's GOESEast.
Learn more in our #SatelliteSnapshot: bit.ly/3NVBiT5
The arctic blast that put much of Florida into a deep freeze also created these mesmerizing cloud streets caught by bsky.app/profile/noaa.gov 's GOESEast.
Learn more in our #SatelliteSnapshot: bit.ly/3NVBiT5
February 4, 2026 at 12:14 AM
From NOAA Satellites:
The arctic blast that put much of Florida into a deep freeze also created these mesmerizing cloud streets caught by bsky.app/profile/noaa.gov 's GOESEast.
Learn more in our #SatelliteSnapshot: bit.ly/3NVBiT5
The arctic blast that put much of Florida into a deep freeze also created these mesmerizing cloud streets caught by bsky.app/profile/noaa.gov 's GOESEast.
Learn more in our #SatelliteSnapshot: bit.ly/3NVBiT5
This is a good listen and explains a lot about the inability of so many powerful voices in the media to meet the moment
Today on Volts: I'm joined by the great @michaelhobbes.bsky.social to discuss "reactionary centrism," an intellectual tendency that's come to dominate US public life. You know the type: would never view themselves as conservative, yet finds voluntary pronoun use vastly more aggravating than fascism.
All about "reactionary centrism"
Michael Hobbes joins me to diagnose the pundit class's obsession with scolding the left while the right burns down the house.
www.volts.wtf
February 3, 2026 at 10:14 PM
This is a good listen and explains a lot about the inability of so many powerful voices in the media to meet the moment
Reposted by Katie Mack
Launch delayed 'til March due to hydrogen leaks, a balky hatch, need to launch a crew to Space Station, & geometry with the Moon.
Next opportunities: March 6, 7, 8, 9, 11.
Sorry, families. Another month of training & preparation to get it all right.
The Moon will patiently wait.
(photo NASA KSC)
Next opportunities: March 6, 7, 8, 9, 11.
Sorry, families. Another month of training & preparation to get it all right.
The Moon will patiently wait.
(photo NASA KSC)
February 3, 2026 at 3:36 PM
Launch delayed 'til March due to hydrogen leaks, a balky hatch, need to launch a crew to Space Station, & geometry with the Moon.
Next opportunities: March 6, 7, 8, 9, 11.
Sorry, families. Another month of training & preparation to get it all right.
The Moon will patiently wait.
(photo NASA KSC)
Next opportunities: March 6, 7, 8, 9, 11.
Sorry, families. Another month of training & preparation to get it all right.
The Moon will patiently wait.
(photo NASA KSC)
Reposted by Katie Mack
Reposted by Katie Mack
I hear there was a "war on protein"? yeah, well, seitan won it and must be greeted as a liberator
February 2, 2026 at 11:31 PM
I hear there was a "war on protein"? yeah, well, seitan won it and must be greeted as a liberator
Reposted by Katie Mack
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
Horrifying. ICE confirms measles outbreak at Dilley family detention center. www.cbsnews.com/news/ice-dil...
ICE halts "all movement" at Texas detention facility due to measles infections
The measles cases at the Dilley Immigration Processing Center were detected Friday, Department of Homeland Security spokesperson Tricia McLaughlin said in a statement to CBS News.
www.cbsnews.com
February 2, 2026 at 4:52 AM
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
Reposted by Katie Mack
In many of the first generation of modern concentration camp systems (near the turn of the twentieth century), the vast majority of deaths were caused by disease and malnutrition. Most of the victims were women and children.
It appears there is now a measles outbreak at the Dilley family detention facility. www.sacurrent.com/news/san-ant...
Source: Measles outbreak reported at ICE's Dilley family detention facility
DPS troopers stand guard in front of the Dilley detention center during a protest last weekend. After a week of public outcry over the Dilley, Texas South
www.sacurrent.com
February 2, 2026 at 12:29 AM
In many of the first generation of modern concentration camp systems (near the turn of the twentieth century), the vast majority of deaths were caused by disease and malnutrition. Most of the victims were women and children.
Reposted by Katie Mack
there are so many impeachable offenses that you now need two wheelbarrows full of impeachable offenses to purchase a simple loaf of bread
February 1, 2026 at 11:27 PM
there are so many impeachable offenses that you now need two wheelbarrows full of impeachable offenses to purchase a simple loaf of bread
Reposted by Katie Mack
Because I'm talking about measles. It is also A VERY VERY VERY CONTAGIOUS VIRUS. If someone is in a room and has measles and then leaves that room and you enter that room within TWO HOURS (depending on humidity) you can get measles.
And people are contagious for four days before the rash appears.
And people are contagious for four days before the rash appears.
::taps mic::
beyond being an absolutely miserable illness, measles can cause immune amnesia. It wipes out your immune systems memory of how to fight every infection, every vaccine you've ever had.
beyond being an absolutely miserable illness, measles can cause immune amnesia. It wipes out your immune systems memory of how to fight every infection, every vaccine you've ever had.
February 1, 2026 at 1:59 AM
Because I'm talking about measles. It is also A VERY VERY VERY CONTAGIOUS VIRUS. If someone is in a room and has measles and then leaves that room and you enter that room within TWO HOURS (depending on humidity) you can get measles.
And people are contagious for four days before the rash appears.
And people are contagious for four days before the rash appears.
Rather depressing afternoon searching the names of fellow physicists in the Epstein files 😑
January 31, 2026 at 10:45 PM
Rather depressing afternoon searching the names of fellow physicists in the Epstein files 😑
Reposted by Katie Mack
This judge does the thing quoting the Declaration of Independence at the Trump regime then adds for good measure: "Observing human behavior confirms that for some among us, the perfidious lust for unbridled power & the imposition of cruelty in its quest know no bounds & are bereft of human decency."
Order to release Adrian and Liam Arias is a real barn burner storage.courtlistener.com/recap/gov.us...
January 31, 2026 at 9:11 PM
This judge does the thing quoting the Declaration of Independence at the Trump regime then adds for good measure: "Observing human behavior confirms that for some among us, the perfidious lust for unbridled power & the imposition of cruelty in its quest know no bounds & are bereft of human decency."
Reposted by Katie Mack
Federal judge has ordered the release of Liam Ramos (the bunny hat boy) and his father. A brief and rather remarkable order. Clearly written to be shared widely, so please do. storage.courtlistener.com/recap/gov.us...
January 31, 2026 at 8:42 PM
Federal judge has ordered the release of Liam Ramos (the bunny hat boy) and his father. A brief and rather remarkable order. Clearly written to be shared widely, so please do. storage.courtlistener.com/recap/gov.us...
All this news is really completely confirming all my unfair knee-jerk judgments about a certain cadre of rich/famous douchebags, I gotta say
January 31, 2026 at 5:42 PM
All this news is really completely confirming all my unfair knee-jerk judgments about a certain cadre of rich/famous douchebags, I gotta say
Reposted by Katie Mack
As a side note, it’s funny to see so many of these emails with thirsty academics repeatedly enact Marx’s bit in the 1844 Manuscripts about the power of money. “Oh Mr Epstein, your house in New York is enormous and, unrelatedly, your questions at dinner were so intelligent, so insightful, so deep.”
![That which is for me through the medium of money - that for which I can pay (i.e., which money can buy) - that am I myself, the possessor of the money. The extent of the power of money is the extent of my power. Money's properties are my - the possessor's - properties and essential powers. Thus, what I am and am capable of is by no means determined by my individuality. I am ugly, but I can buy for myself the most beautiful of women.
Therefore I am not ugly, for the effect of ugliness - its deterrent power - is nullified by money. I, according to my individual characteristics, am lame, but money furnishes me with twenty-four feet.
Therefore I am not lame. I am bad, dishonest, unscrupulous, stupid; but money is honoured, and hence its possessor. Money is the supreme good, therefore its possessor is good. Money, besides, saves me the trouble of being dishonest: I am therefore presumed honest. I am brainless, but money is the real brain of all things and how then should its possessor be brainless? Besides, he can buy clever people for himself, and is he who has [In the manuscript: is. - Ed.] power over the clever not more clever than the clever? Do not I, who thanks to money am capable of all that the human heart longs for, possess all human capacities? Does not my money, therefore, transform all my incapacities into their contrary?](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:myqic77tkmdhmaufgkvj43hr/bafkreidpuxbx764xh7vobavcnvs3v2lo5fnfi6dukfrmk3ygxmseznkyxi@jpeg)
January 31, 2026 at 4:05 PM
As a side note, it’s funny to see so many of these emails with thirsty academics repeatedly enact Marx’s bit in the 1844 Manuscripts about the power of money. “Oh Mr Epstein, your house in New York is enormous and, unrelatedly, your questions at dinner were so intelligent, so insightful, so deep.”
it’s too cold to use the crying emoji, the tears would freeze on the way down
January 31, 2026 at 1:51 PM
it’s too cold to use the crying emoji, the tears would freeze on the way down
Reposted by Katie Mack
An entire political movement founded on uncovering hidden messages in documents to discover the powerful secret pedophiles and meanwhile the powerful pedophiles out here sending gmails saying "Hi fellow pedophile when are we meeting to do pedophilia again"
Disgusting.
In an email on Sept. 11, 2013, Mr. Richard Branson, founder of the Virgin Group, wrote to Mr. Epstein, “It was really nice seeing you yesterday.” He added: “Any time you’re in the area would love to see you. As long as you bring your harem!”
www.nytimes.com/live/2026/01...
In an email on Sept. 11, 2013, Mr. Richard Branson, founder of the Virgin Group, wrote to Mr. Epstein, “It was really nice seeing you yesterday.” He added: “Any time you’re in the area would love to see you. As long as you bring your harem!”
www.nytimes.com/live/2026/01...
Live Updates: Millions of Pages of Epstein Documents Released
www.nytimes.com
January 31, 2026 at 11:47 AM
An entire political movement founded on uncovering hidden messages in documents to discover the powerful secret pedophiles and meanwhile the powerful pedophiles out here sending gmails saying "Hi fellow pedophile when are we meeting to do pedophilia again"
Reposted by Katie Mack
www.youtube.com/shorts/z4dy0...
A video from board-certified ophthalmologist a @glaucomflecken.bsky.social - FYI if you ever get pepper spray somehow onto you, in some manner.
A video from board-certified ophthalmologist a @glaucomflecken.bsky.social - FYI if you ever get pepper spray somehow onto you, in some manner.
What To Do If You Get Pepper Sprayed
YouTube video by Dr. Glaucomflecken
www.youtube.com
January 30, 2026 at 3:04 AM
www.youtube.com/shorts/z4dy0...
A video from board-certified ophthalmologist a @glaucomflecken.bsky.social - FYI if you ever get pepper spray somehow onto you, in some manner.
A video from board-certified ophthalmologist a @glaucomflecken.bsky.social - FYI if you ever get pepper spray somehow onto you, in some manner.
There's an interesting new paper out today (not yet peer reviewed) suggesting an explanation for a weird phenomenon seen with JWST that might point to a "hitherto unobserved physical phenomenon," proposed in a couple of previous papers, called "black hole stars." arxiv.org/abs/2601.20929 1/🧵
Little Red Dot $-$ Host Galaxy $=$ Black Hole Star: A Gas-Enshrouded Heart at the Center of Every Little Red Dot
The central engines of Little Red Dots (LRDs) may be ``black hole stars" (BH*s), early stages of black hole growth characterized by dense gas envelopes. So far, the most direct evidence for BH*s comes...
arxiv.org
January 30, 2026 at 10:56 PM
There's an interesting new paper out today (not yet peer reviewed) suggesting an explanation for a weird phenomenon seen with JWST that might point to a "hitherto unobserved physical phenomenon," proposed in a couple of previous papers, called "black hole stars." arxiv.org/abs/2601.20929 1/🧵
Reposted by Katie Mack
This paper, out today, caught my eye. It's about the mass function of stars — how many stars of a given mass exist — in massive, early galaxies, and it runs counter to a lot of people's expectations. It's related to some of the excitement about JWST and the earliest epochs of galaxy formation. 🧪🧵
Bottom-heavy initial mass functions reveal hidden mass in early galaxies
JWST observations have revealed that massive galaxies formed and evolved far faster than predicted by galaxy formation models, with many having already assembled a large mass in stars $\sim12$ billion...
arxiv.org
January 29, 2026 at 7:47 PM
This paper, out today, caught my eye. It's about the mass function of stars — how many stars of a given mass exist — in massive, early galaxies, and it runs counter to a lot of people's expectations. It's related to some of the excitement about JWST and the earliest epochs of galaxy formation. 🧪🧵
Reposted by Katie Mack
Tonight I watched Prime Minister Mark Carney take the actual Heated Rivalry Canada fleece from Hudson Williams, slip it on and say: “This is true soft power.”
January 30, 2026 at 12:41 AM
Tonight I watched Prime Minister Mark Carney take the actual Heated Rivalry Canada fleece from Hudson Williams, slip it on and say: “This is true soft power.”