Priyamvada Natarajan—

Rather unusually, the team leaders who led the observational efforts that discovered dark energy were awarded the Nobel Prize in 2009 for a discovery from 1998, a rather swift reward by normal standards in physics. According to Alfred Nobel’s wishes, this annual physics prize can be awarded to no more than three people in a given year. This stricture has posed new problems for physics, and in particular cosmology, where, because of the intellectual maturity of the field, cutting-edge research is increasingly conducted in fairly large collaborations. The process of sifting out three individuals to honor for any pathbreaking discovery that was essentially a group effort is increasingly difficult, leading inevitably to unhappy researchers come the second week of October. Astronomy as a field is rarely recognized, but the 2009 award of the Nobel Prize in Physics went to Riess and Schmidt from the High-z team and Perlmutter from the Supernova Cosmology Project for the discovery of dark energy. This led to great debates about dark energy’s many unsung heroes.

Soon after the announcement, there were many public pleas for the Nobel committee to consider research teams for physics awards. No changes have been made to the rules, and the issue of partitioning credit and parceling awards is still fraught—in particular, because the accumulation of knowledge that leads to breakthroughs today has multiple key contributors whose collective work leads to progress. Some of the more recently instituted prestigious prizes have recognized this shift in the working culture of science and have begun awarding entire collaborations. The Gruber Foundation, for instance, has led the way, awarding its prize in cosmology in 2006 to the entire COBE team and in 2007 to both of the teams that discovered dark energy. In a practice pioneered by the COBE team, the discoverers of dark energy invited their entire collaborations to participate and share in the festivities in Stockholm on December 10, 2009. The Breakthrough Prize, founded by the Russian billionaire Yuri Milner in 2012, has been set up to award several individuals as well as teams if warranted. Milner, a former physicist who made his fortune in investment banking, is an enthusiastic supporter of the sciences in his philanthropy. He established Breakthrough Prizes in fundamental physics, mathematics, and life sciences. In 2013 the Breakthrough Prize in Fundamental Physics was awarded to the team leaders of the various groups that were involved in the discovery of the Higgs boson at CERN, and in 2015 it was awarded to both the Supernova Cosmology Project and the High-z Supernova Search Team. How to partition credit in a just fashion is one of the new challenges of the way that scientific work is presently organized and conducted.

The scientific questions that are at the forefront of cosmology today—namely, unraveling the nature of dark matter and dark energy— require the efforts of large, international collaborations. As the historian of science Peter Galison writes, “Big science entails a change in the very nature of a life in science. Teamwork and hierarchy characterize daily work.” This scale of operation originally characterized only giant accelerator projects like CERN in particle physics, but cosmology has transformed over the past thirty years into a field that is likewise no longer the domain of lone researchers. Instead, organized teams fight for funding and develop advanced methods and technologies to tackle and coordinate technically challenging tasks—in this case gathering and standardizing supernovae data. As the physicist Wolfgang K. H. Panofsky argues, the very kinds of questions that we have chosen to probe have necessitated this growth in scale: “We simply do not know how to obtain information on the most minute structure of matter (high-energy physics), on the grandest scale of the universe (astronomy and cosmology), or on statistically elusive results . . . without large efforts and large tools.” What is amply clear is that regardless of how the practice of science has transformed because of this scaling up of the enterprise, science cannot survive in isolation from other spheres of society, and its larger context has become ever more important. This is all the more so as scientific research now requires a huge allocation of resources human, technological, and financial.

The process of scientific acceptance of the more recent radical ideas in cosmology—dark matter, the CMBR, and now dark energy —has been somewhat different from the prior mode. The journey to consensus within the scientific community was swift and smooth for the surprising and intriguing observational discovery of dark energy, although it upended our view of the cosmos entirely. There are several reasons for the expeditiousness of this process. Bizarre though it was, the discovery of dark energy made many disparate observations fit together remarkably well. It was almost akin to the final piece in a jigsaw puzzle. For astronomers, the cosmological constant was and is just a number; for theoretical physicists, lambda was and is a deeper concept—the vacuum energy of the universe and a fundamental property of space. The measurements are beyond dispute, but the origin is still an open question. Another reason for this rapid consensus within the field is the intellectually mature stage that cosmology has reached and the concomitant transformation in the practice of this science. The current pace of discoveries is frenetic, driven by rapidly evolving innovative technologies.

How science is done has fundamentally changed in the past thirty years. Because collaborative international teams are conducting the research, the discoveries have also changed consequentially. There is no longer swift overthrowing (or even slow consolidation and honing) of an old theory but instead a deluge of data that raises as many new theoretical questions as it answers. The discovery of dark energy has challenged our deep understanding of physics and highlighted the gaps in our knowledge of the very early universe. Cosmology has also led the way in the ongoing big data revolution in all intellectual disciplines. A new frontier remains to be explored further—the true nature of dark energy—and this has opened up novel sets of questions of an unprecedented kind that hark back to the moment of creation.

Priyamvada Natarajan is professor of astronomy and physics at Yale University and holds the Sophie and Tycho Brahe Professorship at the Dark Center, Niels Bohr Institute in Copenhagen, and an honorary professorship at the University of Delhi, India.

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