R.I.P. Nick Kaiser (1954-2023)
It was with a sense of shock that I heard this afternoon of the death of the age of 68 of cosmologist Nick Kaiser. It seems like only yesterday that we were celebrating the award of the Gruber Prize to Nick, but that was back in 2019. In a field filled with very clever people, Nick was one of the cleverest and also one of the nicest.
I have never worked directly with Nick Kaiser but he had an enormous influence on me, especially early on in my career. When I was doing my PhD, Nick was based in Cambridge and if I remember correctly he was the first person ever to ask me a question during a conference talk when I gave one there in 1987. Nick was never shy about making such interventions, sometimes somewhat mischievously. At first he terrified me because I didn’t know him except by scientific reputation, and didn’t realize what a nice guy he was. His question was actually very helpful, as it allowed me explain something that I’d skipped because I was under time pressure. His response to my explanation was very complimentary and supportive, which encouraged me a lot, and we chatted for quite a while after the session (in a pub). He was very friendly and approachable, and very far from the intimidating character I’d expected. Anyway, his 1984 paper on cluster correlations was the direct motivation for my very first publication (in 1986).
I mentioned yesterday that many of the papers published by the Open Journal of Astrophysics over the last few years have been in the field of weak gravitational lensing. It is safe to say that is a field that was basically created by Nick; see the paper by Kaiser & Squires (1993) that kicked it all off. You could also say the same about the use of redshift-space distortions, concerning which he wrote a seminal paper in 1987. These are two techniques that will be applied in the analysis of data from the Euclid spacecraft, to be launched next month.
These are just a few of things that Nick did. He did many others, always original and always interesting. In recognition of his achievements he was made a Fellow of the Royal Society in 2008, won the Gold Medal of the Royal Astronomical Society in 2017, the Daniel Chalonge and Hector de Vega Medals in 2018, and the Gruber Prize for Astronomy in 2019.
It’s hard to characterize someone of such intellectual breadth, but it always seemed to me that his approach was driven by a very deep physical insight. He was often able to identify what were the fundamental aspects of apparently complicated phenomena and build simple models that captured most of the physics. Using this approach he could penetrate the thickets in which others might get lost. He was perfectly capable of undertaking more complicated calculations to elaborate the details, but he always started by focussing on the basics.
I met Nick many times here and there, usually at conferences. He was always enthusiastic and energetic and entertaining, and was great company to talk to over a drink or several. You always had a good laugh talking to Nick, but you always learnt something too. His son studied in Cardiff some years ago, while I was working there, and Nick sometimes came to visit on the pretext of giving a seminar. I remember once he almost missed his own talk because we were sitting in a pub chatting.
Nick spent recent years in Paris; I remember his presence when I did an online colloquium for the Daniel Chalonge – Hector de Vega School in 2021. He certainly seemed in fine health and good spirits then. Indeed, he gave a talk in the same series that year which you can download here.
Nick’s untimely death is particularly shocking because he was ultra-fit. I think he got hooked on ultra-endurance events while living in Hawaii, as the first Ironman events were held there. Mere marathons were not enough for him. I think I last saw him in person in 2016 during a meeting in Italy. While most of us laboured on the “easy” hiking trails, Nick found them uninteresting and went running off looking for greater challenges.
It still hasn’t really sunk in that Nick has gone. I know I’m not the only one who feels that way. I think the sense of loss will pervade the cosmological community for a considerable time. I send deepest condolences to his family, friends, colleagues and co-workers. He’ll be hugely missed by a huge number of people.
Rest in peace, Nick.
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In the Dark 
June 14, 2023 at 7:40 pm
Oh indeed. I feel so lucky to have been able to spend with him a few weeks in February at KITP in Santa Barbara this year. We had a fabulous time. So much to learn from him and those seminal papers you mentioned. What a loss. A real Mensch with deep desire for deep insights.
June 14, 2023 at 10:03 pm
That’s a shame. I remember Nick in my Part III Maths year in DAMTP in Cambridge, but he was 3 years older than me; did he take a multiple gap year?
His paper with Gordon Squires has introduced me to a second Gordon Squires, physicist!
June 14, 2023 at 10:13 pm
Always entertaining to see what books you recognise in the background of physicist office shots. Misner Thorne & Wheeler for 1 point, two volumes of Landau & Lifshitz for 2 points each, and at extreme top right (to Nick’s left) is David Tabor’s introductory textbook “Gases, liquids and solids”. I’m sure the astrophysics text next to Landau & Lifshitz’s Statistical Physics is an easy one for some.
June 14, 2023 at 10:22 pm
I don’t know but he did his first degree in Leeds, graduating in 1978, and did Part III in 1979. That suggests he may have taken time out before his UG degree. He got his PhD in 1982, which was the year I started in Cambridge.
June 19, 2023 at 10:36 am
Nick was a rebel, and never toed the party line in anything. His father, Tom, was a physics professor (who also won the RAS Gold Medal, just like Nick). With those genes and background obviously Nick would have been expected to go to university to study physics. Therefore, it was only natural that instead he went off to art college. It took a year or two before he admitted defeat and committed to physics.
June 14, 2023 at 11:00 pm
This is a terrible loss. He was, without doubt, the smartest person I ever met. He revolutionized the field multiple times.
And he was a wonderful & kind human. I am who I am today because of Nick. I will miss him dearly.
June 15, 2023 at 4:03 am
This is very shocking. Had met him just last month in Mumbai, where he seemed to completely normal and he had also given a talk at ICTS.
June 15, 2023 at 4:35 am
Nick was a super enthusiastic, creative scientist and a wonderful human being. He introduced me (and all cosmologists) to Gaussian random fields but also to Abbot Ale and the concept (foreign to an American, yet so temptingly familiar) of the chip buddy. He will be sorely missed by many.
June 15, 2023 at 6:37 pm
It’s a chip buttie, ‘buttie’ coming from the fact that the chips (fries in N America) are placed between two slices of buttered bread to make a sandwich. You can’t eat many of those and stay as thin as Nick without doing a lot of exercise.
June 15, 2023 at 8:49 pm
Nick would have surely chuckled over my gaffe – yet another example of Americans not being able to speak proper English!
June 15, 2023 at 9:37 am
Peter captures Nick perfectly here – this is a wonderful description. He will be sorely missed.
June 15, 2023 at 9:52 am
Still reeling from this Gonna take a good while..
Nick was my oldest friend and the best man at my wedding. We went so many places together since we met when we were both seventeen. The world just lost an exceptional physicist and I just lost one the closest friends I’ve ever had and ever will. It’s all I can do to stop myself sobbing at the moment. Still, I must find a way to celebrate his incredible achievements and our enduring friendship. It’s what he would have wanted as the cliché goes….
June 15, 2023 at 10:24 am
That is really sad.
I have just met him for the first time a month ago at the summer school in India. And he was telling that he was going hiking afterwards and also told many stories of his various running/Iron Man experiences.
June 15, 2023 at 10:34 am
I was just chatting with Nick last thursday – so this is an upsetting shock loss of such a dear friend and with our projects unfinshed. I will dearly miss everything about him and lets keep the unmatched legacy of Nicks science alive together.
June 15, 2023 at 10:38 am
Yes, I’m sure there will be some sort of celebration of Nick and his science in due course.
June 15, 2023 at 2:54 pm
Thank you so much for this beautiful piece about Nick. As his partner I can share he was a very kind man.
June 15, 2023 at 7:31 pm
Hi Maureen
I am so sad to find out about Nick. I send my love to you. He was indeed a very kind man and a lovely friend. Please contact me anytime. I’m on Facebook.
June 15, 2023 at 8:21 pm
Please accept my sincere condolences, and best wishes at what must be a very difficult time for you.
July 19, 2023 at 7:37 pm
Hi Maureen, Gary here, I was expecting to see you both in Spain during a train tour when I heard the awful news from a mutual friend. I’m so sorry. I’ve been wanting to get in touch with you, but didn’t know how. Just come across this website now because a friend mentioned it. Hope to speak soon. Much love. (If you can’t see my email, maybe a message through Linked in?)
June 16, 2023 at 12:04 am
I remember talking briefly with Nick briefly (across a dinner table) when I was a graduate student at KIPAC/Stanford. Even in a brief conversation, his profound insight, curiosity and kindness shone through. It left a deep impression on me, and as I continue to learn more from his seminal works, the admiration continues to grow. Sincerest condolences to Nick’s family, friends and colleagues.
June 16, 2023 at 10:47 am
This is so sad. Apart from being a top-level physicist/cosmologist — boy was he smart — he was such a nice, open, funny, unpretentious person to be with. Knowing Nick would be at a meeting always made me look forward to the trip. He is sure to be remembered for a long time.
June 16, 2023 at 2:43 pm
I’m Maureen’s daughter, Kelsey. As my mom said, thank you for this really lovely tribute. We are shocked and heartbroken.
My mom and Nick started dating in 2015/2016ish—in the year after I finished undergrad university. Not long thereafter, he moved to Paris and he and my mom moved in together. Nick was rapidly enveloped into our family, and we spend many Thanksgiving and Christmases together over the years—in Paris, in the States and in Rome, where my fiancé’s family lives.
It’s strange to have had and now to mourn such a connection with someone with whom I have no actual kinship ties. But Nick and I were real pals. My favorite memories of him were as my running buddy.
Whenever I’d visit Paris, he was always up for a morning run. We’d jaunt through the streets and chat, and his curiously about everything and zest for life shone through. He was taking classes to improve his French and would share the latest grammatical perplexity, trying to work out one of the many inconsistencies in French grammar rules. He’d point out a street name or a statue and its import to French history and politics. We’d often stop for a cheeky croissant and cafe au lait mid-run.
Nick was hugely instrumental in coaching me when I trained for my first ever marathon in 2019. Nick offered the night before my longest 20 mile training run to accompany me—not having been training for a marathon himself. He obviously put me to shame the next day in the Paris summer heat as we did laps around Bois de Boulogne until my watch hit 20 miles. He bought me Born to Run as a gift. He taught me how to fuel properly and would regale me with stories from his ultra-marathon days. He mischievously told me of the rule at ultramarathons when scooping Vaseline at an aid station to salve chaffing in unpleasant places—you get one dip in the communal jar.
The last time I saw Nick was in Rome this past Thanksgiving. I was really excited to show him my favorite running route there—the Appian Way. He loved it and appreciated the history as much as I knew he would.
I can only appreciate the astronomy giant that Nick was through the testimonies of others (although we loved to tease him by asking him if he thought aliens were real). But I can say first hand that I knew of the giant that Nick was as a partner to my mom and as my friend. We love you, Nick, and miss you more than you can imagine.
June 19, 2023 at 4:28 am
Thank you, Kelsey! This is a lovely tribute . Nick adored you three 😘
June 17, 2023 at 7:59 am
Since running and intellectual giants came up, here are some Manoa (Hawaii) memories…
Every now and then, Nick and I would go on 10-mile runs after work, starting at IfA Manoa and working our way up to the top of Tantalus. All on roads except for the steepest part back down, where we’d bounce off roots and rocks on the trails, trying to get out of the rainforest before dark.
On the seemingly endless climb up the switchbacks, as we are jogging in the middle of the road (no traffic…), Nick would invariably say something along the lines of “you know, I’ve been thinking about Bell’s Theorem recently….” or “have you noticed this peculiarity about gravitational redshifts…” or “I am sure you’ve seen the paper on…”. Which would cause me to slowly fall behind, mumbling something amounting to little more than “how interesting”. Brilliant theorist that he was, he was probably just thinking aloud and did not expect any even semi-coherent reply from me, but eventually he would notice and put me out of my misery by changing the subject: “anyway, Honu’s coming up…” (Honu is a local half-Ironman triathlon that Nick liked to do as a warmup to the real thing). And then he’d pick up the pace (competitive streak for sure!) and take off on the final mile to the turnaround at the top.
I’ll miss his energy and his laugh – well, more of a cackle, really! 🙂
The next 10 miles are for you, Nick. Aloha nui.
June 18, 2023 at 1:10 am
Dreadful and terribly sad news . I have known Nick since we were both about 15 years old. He has been part of my family since then. His parents Tom and Pam took us sisters under their wing when my parents lived in Zambia and my eldest sister was dating Nick’s brother Kim. Another brilliant scientist , also sadly gone . They were the kindest , most interesting and fun people too . Nick married my sister Pel , and although they divorced after many years of marriage they remained good friends and I am happy they met up in Hawaii recently. It has been very traumatic for us all, especially his sons Alex and Louis . I have just returned from Paris where Alex was visiting . They had enjoyed a wonderful day together and Nick died peacefully in his arms.All still in shock .We all loved Nick and he will be missed terribly . Many, many great memories . So sorry for all who loved him .Gone but not forgotten . RIP Nick
June 26, 2023 at 7:12 am
Thank you for sharing this Betty. I knew Pel, Alex, & Louis when I was in Hawai’i as Nick’s graduate student. Please pass along my sincere condolences to them and also to you. He was a dear man and touched everyone who knew him.
June 18, 2023 at 7:30 pm
As others, I’m also deeply shocked and saddened by this news.
Nick was responsible for getting me into astronomy… in early 1986 I was dithering about doing a PhD, went to an IoA Cambridge open day and Nick gave me 20 mins explaining his ongoing work about redshift-space distortion, that got me hooked.
I got accepted by IoA and started in Sept 1986; Shaun Cole and I were Nick’s first PhD students, he was great to work with and very encouraging. That led to my first paper, on which Nick should have been a co-author, but with typical generosity he said it would be better for my prospects to be sole-author, so he took his name off it. In late 1987 Nick was poached by CITA for a tenured position (I think he had a senior postdoc at IoA); as I was leaning towards data-crunching, I decided to stay and switched supervisor to George Efstathiou and the APM Galaxy Survey.
I met Nick again many times at conferences through the 1990s, though this usually
involved a lot of drinking so memories are slightly fuzzy.
That APM Galaxy Survey then laid the foundations for 2dFGRS later on, and so it was great that in 2001 Peacock et al got the first decisive detection of Nick’s predicted redshift-space distortion.
Oddly enough in the 2000’s both Nick and I went into the challenging task of building survey telescopes, Nick on PanSTARRS and me on VISTA; we met occasionally at SPIE meetings, though our talk leaned towards more mundane stuff like schedule milestones, hexapods and budget headaches.
The last time I met Nick was an RAS meeting shortly after his Gold Medal; he was in usual fine form and I can’t quite believe he’s gone so soon. RIP Nick, and thanks for everything.
June 19, 2023 at 11:05 am
It’s taken me a while to feel able to write anything here. I knew Nick for over 40 years, and he was one of my closest friends. I saw him as a model for how a scientist should be: broad in his interests, bursting with originality, and above all consumed with a sense of fun in everything he did – though at the same time capable of working really hard when something gripped him. I never met Feynman, but a lot of what I’ve read about him reminds me of Nick. Despite everything that he achieved, Nick never became pompous or rested on his laurels: he was always looking forward to some new intellectual challenge, whether in thermodynamics or French grammar. Being with Nick was always a question of trying to keep up, either with pieces of physics that he seemed to grasp so readily, or with ascents of mountains where I was regularly left gasping in his wake. But I gained so much from spending time with him, and it’s hard to accept that there will be no more.
June 26, 2023 at 7:02 am
Nick was my PhD advisor at the University of Hawai’i (2007). He was a huge part of a significant phase in my life… he was a mentor and a friend. I have no words. Much love to all of you who share in this grief.
July 3, 2023 at 10:09 am
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July 8, 2023 at 9:18 am
Thanks Peter for posting this remembrance of Nick. The news was very sad and unexpected and is a great loss.
I seem to have met Nick every alternate year in the last 30 years since I was a PhD student. It was always the best. The last time was in Paris in 2019 just before the pandemic where we enjoyed a drink at a sidewalk bar. He was always wonderful fun to talk to and hang out with, and it was always fun to ask him about John. 🙂 Nick was such a wonderful, warm and funny person and I very much appreciated his down to earth nature, despite being one of the smartest people I have ever met.
My heartfelt condolences to his family, at least he passed surrounded by them.
I have very much appreciated reading all these posts remembering Nick, especially those from his family who bring a new perspective. Thank you everyone.