Sesh Nadathur
@seshnadathur.bsky.social
Astronomer, Associate Professor of cosmology at Portsmouth. Works on galaxy redshift surveys, from telescopes on remote mountaintops or in space. Dad, occasional climber, likes cricket. Occasionally has opinions.
So true.
I'm perfectly aware this is by far not the worst thing he's done, but Trump's constant presence - day after day after day - in the lives and headspaces of hundreds of millions of people (billions?), in the US and outside, is so taxing. Every morning, we wake up and have to think about this asshole.
January 19, 2026 at 8:55 AM
So true.
Reposted by Sesh Nadathur
I think it would be quite nice for me to be able to wake up in the morning and think about my plans for the day, and more broadly about my own little life, instead of immediately having to ponder the overnight actions of The Guy Over There
January 19, 2026 at 8:43 AM
I think it would be quite nice for me to be able to wake up in the morning and think about my plans for the day, and more broadly about my own little life, instead of immediately having to ponder the overnight actions of The Guy Over There
Reposted by Sesh Nadathur
If you stare at this movie it looks like nothing is happening, but then you notice groups of lines appearing and disappearing.
No, you're not on drugs - it's math.
No, you're not on drugs - it's math.
And now I'm trying my hand at animating them by making the phase shift:
(Mathematical art, I guess.)
Phase-shifting the Fourier transform of a regular 14-gon. Or equivalently: seven plane waves meeting at equal angles.
Phase-shifting the Fourier transform of a regular 14-gon. Or equivalently: seven plane waves meeting at equal angles.
January 10, 2026 at 10:20 PM
If you stare at this movie it looks like nothing is happening, but then you notice groups of lines appearing and disappearing.
No, you're not on drugs - it's math.
No, you're not on drugs - it's math.
If you are close to Portsmouth and interested in an evening learning about astronomy and our place in the Universe, come to our Stargazing public event! 28th Jan, free entry but booking essential. There will be lots of hands-on demos and public talks (including one by me). www.port.ac.uk/stargazing
January 10, 2026 at 11:27 AM
If you are close to Portsmouth and interested in an evening learning about astronomy and our place in the Universe, come to our Stargazing public event! 28th Jan, free entry but booking essential. There will be lots of hands-on demos and public talks (including one by me). www.port.ac.uk/stargazing
Reposted by Sesh Nadathur
The prize is the Lancelot M. Berkeley – New York Community Trust Prize and Daniel Eisenstein (on behalf of the DESI collaboration) is receiving it
January 9, 2026 at 12:02 AM
The prize is the Lancelot M. Berkeley – New York Community Trust Prize and Daniel Eisenstein (on behalf of the DESI collaboration) is receiving it
Reposted by Sesh Nadathur
Looks like we might have the first time AI directly solved an open Erdos problem: github.com/teorth/erdos...
A couple times recently this appeared to be the case only to turn out to be a successful deep lit review by AI.
A couple times recently this appeared to be the case only to turn out to be a successful deep lit review by AI.
January 7, 2026 at 5:12 PM
Looks like we might have the first time AI directly solved an open Erdos problem: github.com/teorth/erdos...
A couple times recently this appeared to be the case only to turn out to be a successful deep lit review by AI.
A couple times recently this appeared to be the case only to turn out to be a successful deep lit review by AI.
I got a few of these this year, and yeah, probably don't do that. But absolutely never in any circumstances email to say "I saw this position you advertised and I'd like to apply, but can you please change the project to something else I'd rather work on instead?" 🙄
4. Don't email the PI saying "I'm interested in this PhD position you advertised and if you think I should apply, let me know and I'll send you my CV" The ad is our invitation for your to send your CV. We are very busy and in most situations, probably won't respond at all to that kind of email.
January 5, 2026 at 9:58 PM
I got a few of these this year, and yeah, probably don't do that. But absolutely never in any circumstances email to say "I saw this position you advertised and I'd like to apply, but can you please change the project to something else I'd rather work on instead?" 🙄
Reposted by Sesh Nadathur
The US is more dangerous to the stability of the world and democratic states than China and just as dangerous and hostile as Russia. This is the realist position.
January 3, 2026 at 7:44 AM
The US is more dangerous to the stability of the world and democratic states than China and just as dangerous and hostile as Russia. This is the realist position.
I've always liked Khawaja - one of the most interesting people in world cricket IMV. I'm glad he gets to call time on an excellent career on his own terms.
www.espncricinfo.com/story/usman-...
www.espncricinfo.com/story/usman-...
Khawaja to retire from international cricket after SCG Ashes finale
Usman Khawaja will play his final Test at the SCG, the ground where his career started in early 2011
www.espncricinfo.com
January 2, 2026 at 11:07 AM
I've always liked Khawaja - one of the most interesting people in world cricket IMV. I'm glad he gets to call time on an excellent career on his own terms.
www.espncricinfo.com/story/usman-...
www.espncricinfo.com/story/usman-...
Brydon Carse - I guess no option but for him to play this game, given Archer is out. But why is he still opening the bowling?!
December 26, 2025 at 12:01 AM
Brydon Carse - I guess no option but for him to play this game, given Archer is out. But why is he still opening the bowling?!
I just became aware of an astronomy paper from a large collaboration where the lead author appears* to have asked an LLM to help inputting all co-author names in the arXiv metadata ...
... and guess what, the LLM made up a bunch of names. Out there on the arXiv with fictitious authors 😬
🧪🔭
... and guess what, the LLM made up a bunch of names. Out there on the arXiv with fictitious authors 😬
🧪🔭
December 22, 2025 at 11:46 AM
I just became aware of an astronomy paper from a large collaboration where the lead author appears* to have asked an LLM to help inputting all co-author names in the arXiv metadata ...
... and guess what, the LLM made up a bunch of names. Out there on the arXiv with fictitious authors 😬
🧪🔭
... and guess what, the LLM made up a bunch of names. Out there on the arXiv with fictitious authors 😬
🧪🔭
Reposted by Sesh Nadathur
Were classical statues painted horribly?
buff.ly/fS78ULM
It is often suggested that modern viewers dislike painted reconstructions of Greek and Roman statues because our taste differs from that of the ancients. This essay proposes an alternative explanation.
buff.ly/fS78ULM
It is often suggested that modern viewers dislike painted reconstructions of Greek and Roman statues because our taste differs from that of the ancients. This essay proposes an alternative explanation.
Were classical statues painted horribly? - Works in Progress Magazine
Many claim that modern viewers dislike painted reconstructions of Greek and Roman statues because our taste differs from theirs.
buff.ly
December 20, 2025 at 9:53 AM
Were classical statues painted horribly?
buff.ly/fS78ULM
It is often suggested that modern viewers dislike painted reconstructions of Greek and Roman statues because our taste differs from that of the ancients. This essay proposes an alternative explanation.
buff.ly/fS78ULM
It is often suggested that modern viewers dislike painted reconstructions of Greek and Roman statues because our taste differs from that of the ancients. This essay proposes an alternative explanation.
Brydon Carse is extremely lucky to be playing this game, and I suspect he won't be in the team for Melbourne. Pretty dreadful first few overs there for England.
December 17, 2025 at 11:46 PM
Brydon Carse is extremely lucky to be playing this game, and I suspect he won't be in the team for Melbourne. Pretty dreadful first few overs there for England.
Reposted by Sesh Nadathur
Two men meet in the carpark of a Leeds hospital. They sit on a bench and start chatting. One of them has a bomb in their backpack and the other must talk them out of using it. A mindblowing and entirely true story that reads like a thriller. as.ft.com/r/13756c02-0...
‘It’s just a bomb’
[FREE TO READ] The true story of two strangers and an extraordinary act of courage
as.ft.com
December 13, 2025 at 9:10 AM
Two men meet in the carpark of a Leeds hospital. They sit on a bench and start chatting. One of them has a bomb in their backpack and the other must talk them out of using it. A mindblowing and entirely true story that reads like a thriller. as.ft.com/r/13756c02-0...
What is also interesting is how much less I pay in tax today than someone on the same nominal income did 3 or 5 years ago. Perhaps not surprising the state can't afford to pay for anything.
I understand what marginal tax rates and how they work, but (with apologies for naive point) the fact that someone on a median income only pays this much tax - given the general state of the discourse on this - is surprising to me
December 12, 2025 at 7:48 PM
What is also interesting is how much less I pay in tax today than someone on the same nominal income did 3 or 5 years ago. Perhaps not surprising the state can't afford to pay for anything.
Just attended a really great colloquium by Brodie Popovic about this paper 🧪🔭
UK colleagues: Brodie is now a Marie Curie fellow at Southampton, and would be a great addition to your seminar schedules.
UK colleagues: Brodie is now a Marie Curie fellow at Southampton, and would be a great addition to your seminar schedules.
Two very interesting papers about dark energy on the arXiv today, both very relevant to the ongoing interest in possibly evolving DE as suggested by the DESI results 🔭🧪
Here's the first and potentially more explosive one: arxiv.org/abs/2511.07517
Here's the first and potentially more explosive one: arxiv.org/abs/2511.07517
The Dark Energy Survey Supernova Program: A Reanalysis Of Cosmology Results And Evidence For Evolving Dark Energy With An Updated Type Ia Supernova Calibration
We present improved cosmological constraints from a re-analysis of the Dark Energy Survey (DES) 5-year sample of Type Ia supernovae (DES-SN5YR). This re-analysis includes an improved photometric cross...
arxiv.org
December 11, 2025 at 3:15 PM
Just attended a really great colloquium by Brodie Popovic about this paper 🧪🔭
UK colleagues: Brodie is now a Marie Curie fellow at Southampton, and would be a great addition to your seminar schedules.
UK colleagues: Brodie is now a Marie Curie fellow at Southampton, and would be a great addition to your seminar schedules.
Reposted by Sesh Nadathur
I thought the most interesting thing about the interview Stokes gave today was that it is the first time I've heard him or McCullum admit that something in their approach isn't working. #TheAshes
December 7, 2025 at 2:20 PM
I thought the most interesting thing about the interview Stokes gave today was that it is the first time I've heard him or McCullum admit that something in their approach isn't working. #TheAshes
I got home from work today to find my kids writing out Christmas cards for all their school friends. The 7-year-old has been signing them off "Yours sincerely"
December 1, 2025 at 10:15 PM
I got home from work today to find my kids writing out Christmas cards for all their school friends. The 7-year-old has been signing them off "Yours sincerely"
It is nice to see this - and I hope it is reflected in UK Space Agency budgets and long term stability of funding here too!
The #CM25 historic increase of 3.5% per year beyond inflation for Science will enable some of the most imaginative missions in our history and bolster European scientific leadership.
First step: deliver the #CosmicVision missions such as LISA & NewAthena. The next great leap is #Voyage2050 🔭 🧪
First step: deliver the #CosmicVision missions such as LISA & NewAthena. The next great leap is #Voyage2050 🔭 🧪
Today marks a milestone for European space exploration. The largest contributions in the history of the European Space Agency, €22.1 billion, were just approved at our Ministerial Council meeting in Bremen, Germany. #CM25
More details 👇 www.esa.int/About_Us/Cor...
More details 👇 www.esa.int/About_Us/Cor...
November 28, 2025 at 5:46 PM
It is nice to see this - and I hope it is reflected in UK Space Agency budgets and long term stability of funding here too!
Timetable discussions for next term with my (lovely) colleagues are sadly bringing home the reality that my five-year research fellowship ends on Dec 31st and I'm going to have to start a new phase of my academic life ... 🧪🔭
November 26, 2025 at 7:53 PM
Timetable discussions for next term with my (lovely) colleagues are sadly bringing home the reality that my five-year research fellowship ends on Dec 31st and I'm going to have to start a new phase of my academic life ... 🧪🔭
Reposted by Sesh Nadathur
the thing that scares me about Labour HE policy is that because I work in the sector I can see how absolutely insane it is, which makes me wonder just how terrible their policies are in all the other sectors I’m in less of a position to engage with critically out of lack of knowledge.
November 23, 2025 at 11:08 PM
the thing that scares me about Labour HE policy is that because I work in the sector I can see how absolutely insane it is, which makes me wonder just how terrible their policies are in all the other sectors I’m in less of a position to engage with critically out of lack of knowledge.
Apropos of nothing in particular, two cosmology questions for my followers:
- in the first figure, are the black or blue contours in better agreement with the pink ones?
- in the second figure, are the black or blue contours in better agreement with (w0,wa)=(-1,0)?
🔭🧪☄️
- in the first figure, are the black or blue contours in better agreement with the pink ones?
- in the second figure, are the black or blue contours in better agreement with (w0,wa)=(-1,0)?
🔭🧪☄️
November 14, 2025 at 7:26 PM
Apropos of nothing in particular, two cosmology questions for my followers:
- in the first figure, are the black or blue contours in better agreement with the pink ones?
- in the second figure, are the black or blue contours in better agreement with (w0,wa)=(-1,0)?
🔭🧪☄️
- in the first figure, are the black or blue contours in better agreement with the pink ones?
- in the second figure, are the black or blue contours in better agreement with (w0,wa)=(-1,0)?
🔭🧪☄️
Two very interesting papers about dark energy on the arXiv today, both very relevant to the ongoing interest in possibly evolving DE as suggested by the DESI results 🔭🧪
Here's the first and potentially more explosive one: arxiv.org/abs/2511.07517
Here's the first and potentially more explosive one: arxiv.org/abs/2511.07517
The Dark Energy Survey Supernova Program: A Reanalysis Of Cosmology Results And Evidence For Evolving Dark Energy With An Updated Type Ia Supernova Calibration
We present improved cosmological constraints from a re-analysis of the Dark Energy Survey (DES) 5-year sample of Type Ia supernovae (DES-SN5YR). This re-analysis includes an improved photometric cross...
arxiv.org
November 12, 2025 at 11:42 AM
Two very interesting papers about dark energy on the arXiv today, both very relevant to the ongoing interest in possibly evolving DE as suggested by the DESI results 🔭🧪
Here's the first and potentially more explosive one: arxiv.org/abs/2511.07517
Here's the first and potentially more explosive one: arxiv.org/abs/2511.07517