The dawn of a new year is a perfect time to pause and reflect, taking stock of the past while also looking forward to the future.
In that dual-introspective spirit, I received an email in late December from Texas A&M astronomer Nick Suntzeff, letting me know that the discovery of dark energy is now 20 years old. He also noted the paper authored by the High-Z Supernova Search Team he co-founded detailing the groundbreaking discovery that the expansion of the universe is accelerating is now the most highly cited paper in the history of astronomy, according to the SAO/NASA Astrophysics Data System (ADS), an online database of more than eight million astronomy and physics papers across both peer-reviewed and non-peer-reviewed sources.
“There is a book ahead of us — Numerical Recipes — but we are the No. 1 cited paper in history,” Suntzeff clarified. “You will find that we are No. 12 of all papers in astronomy and physics.”
The High-Z team featured Australian National University’s Brian Schmidt and Johns Hopkins University/Space Telescope Science Institute’s Adam Riess, co-recipients of the 2011 Nobel Prize in Physics along with the University of California Berkeley’s Saul Perlmutter, who headed up the competing team, the Supernova Cosmology Project, that near-simultaneously reported the same result. Suntzeff had co-founded the High-Z Team along with Schmidt in 1994, at which time Riess was a graduate student finishing his thesis.
“This month 20 years ago, we were doing fits and calculations and having snippets of exciting conversations, and reading and rereading the Carroll, Press, and Turner (1992) ARAA on the Cosmological Constant, having completed image subtraction, photometric solutions, K-corrections, etc., the prior months,” Riess wrote in a December 21 email to his High-Z colleagues. “In two weeks minus 20 years, Brian confirmed my last-step analysis of the likelihood in the Matter/Lambda plane with a Jan 8th email, ‘Well Hello Lambda!’ and a day and a half later, we were all emailing back and forth in one long thread … about what we all thought of this. We were pretty surprised and confused! This AAS meeting is 20 years after Peter G. [Garnavich] discussed Omega_M<1 and kept mum about acceleration*. In February, [it will be] 20 years [since] Jim Glanz reported the story for Science, and on March 13, [it will be] 20 years [since] we submitted the paper. … I remain awed and grateful to have worked with such great colleagues and in such interesting times.”
For his part back then, Suntzeff was an astronomer at the United States National Optical Astronomy Observatory (NOAO)/Cerro Tololo Inter-American Observatory in La Serena, Chile, where he served as the principal investigator on the discovery of the supernova (some 50 of them) whose light was inexplicably weaker than expected — the first indication that the expansion of the universe was accelerating. Prior to that, he had co-founded a previous group, the Calan/Tololo Supernova Project, that used the brightness from a specific type of supernova, Type Ia, to produce not only a precise calibration but also a precise measurement of the Hubble constant — a key finding that paved the way for both teams’ subsequent discovery that merited the 2011 Nobel Prize in Physics, along with the 2015 Breakthrough Prize in Physics, the 2007 Gruber Prize for Cosmology and the 2006 Shaw Prize.
Nearly 20 years later, I would write my initial press release on Suntzeff, announcing his 2006 hire at Texas A&M. At the time, I didn’t know much about him, but I knew it had to be big, given that then-Bryan-College Station Eagle higher education reporter Brett Nauman had heard of him. In fact, he asked me if the rumors of such a coup were true! I distinctly remember being struck by two details in particular: that Suntzeff was part of Science magazine’s Scientific Breakthrough of the Year in 1998 and that he was a co-recipient of the 1983 Robert J. Trumpler Award presented annually by the Astronomical Society of the Pacific in recognition of the most outstanding astronomy thesis of the year granted at North American universities. In combination, these two facts told me all I needed to know – that he was big-time and that he could write, which means he could appreciate not only what I do but also why I do it.
I can’t count the number of times I’ve been proven right on both counts during the past decade, but I do know that one of those memorable occasions was writing the 2007 Gruber Prize announcement — my first release on Suntzeff, now that he officially was at Texas A&M, and my first opportunity to hear his version of the story behind the discovery. Again, I remember being fascinated by a key detail — the fact that every six months, the High-Z team gave its data to different groups at different institutions, ensuring that the highest priority would be given to each part of the problem and enabling them to catch up to Perlmutter’s team at Berkeley. In addition to helping them stake their claim to astronomical history, the unorthodox approach allowed them to give credit where it was due: the postdocs, who in turn were rewarded for all their hard work with first authorship on the team’s resulting papers. I had written enough press releases and research features at this point in my career to know this was a major exception to what I knew thus far as the norm — a fact that Suntzeff confirmed was as unique as it sounded to me, as well as a point of pride for him and the rest of the team, which I found both intriguing and refreshing.
Suntzeff also correctly predicted at the time that the discovery would be honored with the Nobel Prize forthwith. And that there would be a lot of associated angst and heartbreak, considering that, unlike the Gruber Prize shared by 52 international researchers, the Nobel and its global certainty of all but cementing the historical record would go to a maximum of three people. When the inevitable came to pass in October 2011, Suntzeff took it upon himself to congratulate, console and champion his teammates to take heart in all they had accomplished — to a man but more importantly because they did it as a group in the true spirit of team.
“I mean, how many people can say they discovered nearly 75 percent of the universe?” Suntzeff quipped in my paraphrased recollection of his parting words to his teammates.
Fast-forward to present day, when Suntzeff’s co-leader Schmidt summed it up quite nicely himself in his reply-to-all to Riess’ original email, alerting the High-Z team to their top-ranked paper:
Dear Adam —
Thank you for your reminder to us all what an amazing piece of history that all were part of. Not sure how we should celebrate. Perhaps this is the right way to do so — via email, as a group, just like we were working 20 years ago.”
My kind of teamwork and leadership. Happy anniversaries, High-Zers, and here’s to making more future history!
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* A Footnote to History
Peter Garnavich was first author on the High Z team’s paper that preceded Riess et al 1998, further validating the efficacy of their powered-by-postdoc strategy.
“Peter G. was our real unsung hero,” Suntzeff said. “His paper was extremely important because it showed that the expansion rate of the universe over time changes in a manner driven by the total matter of the universe. Peter estimated the total matter content of the universe directly from cosmology and showed that the total matter in the universe was not enough to close it, thereby contradicting Perlmutter et al 1997.
“That HZT paper was the first successful measurement of the content of the universe based on the geometry of the universe. Peter also showed at the same time that if the universe is flat, the universe must be in acceleration. What Riess et al 1998 did was to measure that the universe was in acceleration without the assumption that the universe is flat.”