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.
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
Reposted by Sesh Nadathur
This morning was an epic sunrise in the New Forest. Really nice to get out there with some gorgeous conditions. When there is a low lying mist my favourite place is an old train line which was closed 60 years ago. #EastCoastKin #Scape #Treescape #Horse #Photography #mist
November 8, 2025 at 7:52 PM
This morning was an epic sunrise in the New Forest. Really nice to get out there with some gorgeous conditions. When there is a low lying mist my favourite place is an old train line which was closed 60 years ago. #EastCoastKin #Scape #Treescape #Horse #Photography #mist
Reposted by Sesh Nadathur
despite not having vocals, 'kind of blue' is actually the first kind
November 5, 2025 at 8:33 PM
despite not having vocals, 'kind of blue' is actually the first kind
Reposted by Sesh Nadathur
There are three types of jazz: smoky voiced female vocalist sings song that sounds like it’s about sex but is actually about racism; 9 woodwork teachers on a stage shout “chase that tiger” while somebody hammers a piano; man has a heart attack whilst trumpet playing and falls downstairs.
November 5, 2025 at 8:28 PM
There are three types of jazz: smoky voiced female vocalist sings song that sounds like it’s about sex but is actually about racism; 9 woodwork teachers on a stage shout “chase that tiger” while somebody hammers a piano; man has a heart attack whilst trumpet playing and falls downstairs.
Aren't languages wonderful? Here's an example of Deutsche Bahn not only borrowing from English but also "verbing" a noun in a way that Calvin and Hobbes would respect!
November 4, 2025 at 4:01 PM
Aren't languages wonderful? Here's an example of Deutsche Bahn not only borrowing from English but also "verbing" a noun in a way that Calvin and Hobbes would respect!
I went for a long morning swim in the sea today, on the day the clocks went back. The sea was the Sea of Crete rather than the Solent, which made it less of an achievement but much more pleasurable!
October 26, 2025 at 6:55 AM
I went for a long morning swim in the sea today, on the day the clocks went back. The sea was the Sea of Crete rather than the Solent, which made it less of an achievement but much more pleasurable!
Reposted by Sesh Nadathur
Cosmologists! We have a faculty job going here in Oxford - happy to answer questions. Brief version is that this remains a great & collaborative place to do science and the students are superb. 🔭 www.jobs.ac.uk/job/DOP628/a...
Associate Professor of Cosmology at University of Oxford
Recruiting now: Associate Professor of Cosmology on jobs.ac.uk. Click for details and explore more academic job opportunities on the top job board
www.jobs.ac.uk
October 14, 2025 at 9:16 AM
Cosmologists! We have a faculty job going here in Oxford - happy to answer questions. Brief version is that this remains a great & collaborative place to do science and the students are superb. 🔭 www.jobs.ac.uk/job/DOP628/a...
Reposted by Sesh Nadathur
The Nobel Prize, widely considered the ultimate indicator of important science, has often gone off in weird directions due to politics & personalities.
Like that year when an obsolete form of color photography beat out quantum physics for the physics Nobel. 🧪
physicsworld.com/a/nobel-priz...
Like that year when an obsolete form of color photography beat out quantum physics for the physics Nobel. 🧪
physicsworld.com/a/nobel-priz...
October 8, 2025 at 2:18 PM
The Nobel Prize, widely considered the ultimate indicator of important science, has often gone off in weird directions due to politics & personalities.
Like that year when an obsolete form of color photography beat out quantum physics for the physics Nobel. 🧪
physicsworld.com/a/nobel-priz...
Like that year when an obsolete form of color photography beat out quantum physics for the physics Nobel. 🧪
physicsworld.com/a/nobel-priz...
By the way, although it is a bit late, if you know a cosmologist who would like to use our cosmology chains and other data, they can now get them following the instructions here: www.desi.lbl.gov/2025/10/06/d...
October 6, 2025 at 5:29 PM
By the way, although it is a bit late, if you know a cosmologist who would like to use our cosmology chains and other data, they can now get them following the instructions here: www.desi.lbl.gov/2025/10/06/d...
A special issue splash in Physical Review today on our DESI results:
promo.aps.org/desi_dr2
Which also contains a Featured in Physics viewpoint on the status of cosmology following DESI, by Matteo Viel: physics.aps.org/articles/v18...
promo.aps.org/desi_dr2
Which also contains a Featured in Physics viewpoint on the status of cosmology following DESI, by Matteo Viel: physics.aps.org/articles/v18...
DESI Collection
promo.aps.org
October 6, 2025 at 4:29 PM
A special issue splash in Physical Review today on our DESI results:
promo.aps.org/desi_dr2
Which also contains a Featured in Physics viewpoint on the status of cosmology following DESI, by Matteo Viel: physics.aps.org/articles/v18...
promo.aps.org/desi_dr2
Which also contains a Featured in Physics viewpoint on the status of cosmology following DESI, by Matteo Viel: physics.aps.org/articles/v18...
Reposted by Sesh Nadathur
An actual quote from the Secretary of State for Business and Trade
Too often people go to university to ‘explore research and knowledge’
Look forward to Wes S saying 'too often people go to hospital to have operations' or Heidi Alexander saying 'too often people go to the station to catch a train'
Too often people go to university to ‘explore research and knowledge’
Look forward to Wes S saying 'too often people go to hospital to have operations' or Heidi Alexander saying 'too often people go to the station to catch a train'
September 19, 2025 at 10:25 AM
An actual quote from the Secretary of State for Business and Trade
Too often people go to university to ‘explore research and knowledge’
Look forward to Wes S saying 'too often people go to hospital to have operations' or Heidi Alexander saying 'too often people go to the station to catch a train'
Too often people go to university to ‘explore research and knowledge’
Look forward to Wes S saying 'too often people go to hospital to have operations' or Heidi Alexander saying 'too often people go to the station to catch a train'
Lecturer A had amazingly found a way to use AI that would take even longer and be more work than just doing things without it.
Simply astonishing. Maybe Lecturer A should not have to mark over 100 essays in a two-week window in the first place? Invest in qualified staff and reduce impossible workloads FFS www.kcl.ac.uk/about/strate...
September 17, 2025 at 12:09 PM
Lecturer A had amazingly found a way to use AI that would take even longer and be more work than just doing things without it.
Today would have been the 100th birthday of the great BB King. I was reminded of this and so also remembered this lovely short film of him in London in 1972 (which you can watch on the iPlayer if you're in the UK: www.bbc.co.uk/iplayer/episode/m0023jmg)
B.B. King - Sounding Out - London 1972 [HD 720p]
YouTube video by Yesterdays Today
youtu.be
September 16, 2025 at 7:03 PM
Today would have been the 100th birthday of the great BB King. I was reminded of this and so also remembered this lovely short film of him in London in 1972 (which you can watch on the iPlayer if you're in the UK: www.bbc.co.uk/iplayer/episode/m0023jmg)
Reposted by Sesh Nadathur
Regardless of everything else, Oblique Seville is one of the very best names. #TheAthletics
September 14, 2025 at 1:24 PM
Regardless of everything else, Oblique Seville is one of the very best names. #TheAthletics
My wife is out with friends, so I'm watching season 3 of The Test - and my word that episode about the first Ashes test in 2023 is just amazing TV. Absolutely brilliant.
September 12, 2025 at 9:22 PM
My wife is out with friends, so I'm watching season 3 of The Test - and my word that episode about the first Ashes test in 2023 is just amazing TV. Absolutely brilliant.
Reposted by Sesh Nadathur
All illusions that russia wants only Ukraine — or that it would stop after getting the Donetsk region — should be gone after this blatant attack on Poland.
russia seeks to restore its borderless empire.
Ukraine's security is Europe's security.
Time to choose to defeat russia.
russia seeks to restore its borderless empire.
Ukraine's security is Europe's security.
Time to choose to defeat russia.
September 10, 2025 at 6:57 AM
All illusions that russia wants only Ukraine — or that it would stop after getting the Donetsk region — should be gone after this blatant attack on Poland.
russia seeks to restore its borderless empire.
Ukraine's security is Europe's security.
Time to choose to defeat russia.
russia seeks to restore its borderless empire.
Ukraine's security is Europe's security.
Time to choose to defeat russia.
I will be on The Sky at Night on BBC4 tonight, talking about dark energy and the expanding universe.
Here's a little clip from the conversation: www.bbc.co.uk/programmes/p...
Here's a little clip from the conversation: www.bbc.co.uk/programmes/p...
BBC Four - The Sky at Night, The Expanding Universe, DESI Rewrites the Textbooks
Physics is different now?!
www.bbc.co.uk
September 8, 2025 at 5:00 PM
I will be on The Sky at Night on BBC4 tonight, talking about dark energy and the expanding universe.
Here's a little clip from the conversation: www.bbc.co.uk/programmes/p...
Here's a little clip from the conversation: www.bbc.co.uk/programmes/p...
Reposted by Sesh Nadathur
"Sweeteners can harm cognitive health equivalent to 1.6 years of ageing, study finds"
Or does it? Let's take a look at this "study"...
www.theguardian.com/food/2025/se...
Or does it? Let's take a look at this "study"...
www.theguardian.com/food/2025/se...
Sweeteners can harm cognitive health equivalent to 1.6 years of ageing, study finds
Researchers say low- and no-calorie sweeteners appear to affect thinking and memory in middle age
www.theguardian.com
September 5, 2025 at 4:46 PM
"Sweeteners can harm cognitive health equivalent to 1.6 years of ageing, study finds"
Or does it? Let's take a look at this "study"...
www.theguardian.com/food/2025/se...
Or does it? Let's take a look at this "study"...
www.theguardian.com/food/2025/se...
A little piece of free career advice for any astronomers: do not enter a scientific collaboration with anyone from the University of Florida astro department.
September 3, 2025 at 7:37 AM
A little piece of free career advice for any astronomers: do not enter a scientific collaboration with anyone from the University of Florida astro department.
Great news that as a collaboration we in DESI have been awarded the Lancelot M. Berkeley-New York Community Trust prize for meritorious work in astronomy for 2026! The citation specifically references our two BAO cosmology papers, which are very close to my heart 💜
🌟 We’re proud to share that the DESI Collaboration has been awarded the 2026 Lancelot M. Berkeley–New York Community Trust Prize by the American Astronomical Society (AAS) — read more on the AAS website aas.org/press/desi-c... 🎉
DESI Collaboration to Receive 2026 Berkeley Prize | American Astronomical Society
The Dark Energy Spectroscopic Instrument (DESI) collaboration will receive the 2026 Lancelot M. Berkeley − New York Community Trust Prize for Meritorious Work in Astronomy for its work constraining po...
aas.org
August 26, 2025 at 11:01 PM
Great news that as a collaboration we in DESI have been awarded the Lancelot M. Berkeley-New York Community Trust prize for meritorious work in astronomy for 2026! The citation specifically references our two BAO cosmology papers, which are very close to my heart 💜
What a great little documentary, that I was totally unaware of until today
"Race and Pace", about the West Indies cricketers in the Lancashire League is excellent as well.
m.youtube.com/watch?v=XPzx...
m.youtube.com/watch?v=XPzx...
Race And Pace-West Indies Cricketers in the Lancashire Leagues
YouTube video by The Mix-Up
m.youtube.com
August 18, 2025 at 8:28 PM
What a great little documentary, that I was totally unaware of until today
Reposted by Sesh Nadathur
In her first race in over a year since winning Olympic gold, 🇬🇧Keely Hodgkinson sets a new 800m world lead by almost TWO SECONDS in 1:54.74!! 😳#SilesiaDL
Just .13s away from her PB and the 9th fastest time in WORLD HISTORY! #trackandfield
Just .13s away from her PB and the 9th fastest time in WORLD HISTORY! #trackandfield
August 16, 2025 at 1:58 PM
In her first race in over a year since winning Olympic gold, 🇬🇧Keely Hodgkinson sets a new 800m world lead by almost TWO SECONDS in 1:54.74!! 😳#SilesiaDL
Just .13s away from her PB and the 9th fastest time in WORLD HISTORY! #trackandfield
Just .13s away from her PB and the 9th fastest time in WORLD HISTORY! #trackandfield
I tried using an LLM to help with a tedious but not too complicated coding task today, and was genuinely surprised how poorly it worked. In the end I realised it was wasting rather than saving time, so I wrote the code myself.
Brief description to follow in the thread below.
1/
Brief description to follow in the thread below.
1/
August 13, 2025 at 8:40 PM
I tried using an LLM to help with a tedious but not too complicated coding task today, and was genuinely surprised how poorly it worked. In the end I realised it was wasting rather than saving time, so I wrote the code myself.
Brief description to follow in the thread below.
1/
Brief description to follow in the thread below.
1/
Fourth location is the Kobayashi Maskawa Institute at Nagoya University, where I will give a seminar that is also part of an HSC medium band workshop. Nagoya is nice but also very hot and humid, 40C yesterday 🥵
August 6, 2025 at 3:16 AM
Fourth location is the Kobayashi Maskawa Institute at Nagoya University, where I will give a seminar that is also part of an HSC medium band workshop. Nagoya is nice but also very hot and humid, 40C yesterday 🥵