Beatrice Tinsley, Astronomer Who Saw the Course of the Universe
S E E D E D C O N T E N T
In 1967 a very prominent astronomer visited Dallas to give a talk. Before he could speak, however, a young woman named Beatrice Tinsley stood up and told the audience that everything they were about to hear was wrong.
Beatrice Tinsley at an International Astronomical Union symposium in Tallinn, Estonia, in 1977.
J. Richard Gott
On one side was Allan Sandage, arguably the most important astronomer in the world, who was convinced that he was homing in on the fate of the universe — namely, that it was doomed to collapse one distant day, a hundred billion years from now.
On the other side was an outspoken 26-year-old graduate student, who was saying that Sandage had misread the light of distant galaxies and, with it, the fate of the universe.
Sandage was outraged, but history would record that Tinsley won that argument.
In the years ahead, before cancer struck her down on March 23, 1981, at the age of 40, Tinsley would become known as the world’s leading expert on the aging and evolution of galaxies — the gigantic glowing stellar metropolises that are the true citizens of the cosmos.
In her work, which the Princeton astronomer James Gunn called “a real paradigm change,” galaxies went from being considered isolated blobs of starlight to dynamic changeable weather centers of energy and radiation, influencing and being influenced by the cosmos around them.
Tinsley was the sparkplug of a new generation of astronomers and physicists who were using new methods and data to wrest the narrative of the universe from their elders. Friends and colleagues recalled her as passionate about her ideas and the universe and also as a feminist hero to the tiny but growing band of women in astronomy — one who had to pay a steep personal price, in the form of abandoning her family, to follow her stars.
Asteroids, mountains, lectureships and awards have since been named for her, but a lifetime of glass ceilings and rejections left Tinsley often feeling unappreciated.
“She never lost the feeling of fighting the world,” said Richard Larson, a Yale astronomer who became a collaborator and close friend.
Beatrice Muriel Hill was born in Chester, England, on Jan. 27, 1941, and grew up in New Zealand, the middle of three daughters of Jean and Edward Hill. Her father was a clergyman turned politician who became mayor of New Plymouth in New Zealand.
“Beetle,” as her friends and family called her, had a healthy disrespect for authority, which would influence her attitudes toward both science and religion. As she grew up her two loves were music and mathematics.
At the University of Canterbury in Christchurch, New Zealand, she fell under the spell of physics, learning, as quoted in a biographical memoir by her father, “to question everything.” In 1961 she married a fellow physicist and classmate, Brian Tinsley. A year later she emerged with a master’s degree, but could not find work at Canterbury because her husband worked there.
When her husband was recruited to the Southwest Center for Advanced Studies in Dallas — now the University of Texas at Dallas — she followed, but found the situation stultifying. She once caused a minor scandal by refusing to host a faculty tea when it was her turn. In 1964 she enrolled as a graduate student at the University of Texas at Austin, the only woman in the program, commuting 400 miles every week.
It was while simulating the effects of the evolution of billions of stars on the overall appearance of galaxies that she crossed swords with Allan Sandage.
The fate of the universe was the big question in cosmology. Would the universe keep expanding forever? Or would the combined gravity of the galaxies eventually pull everything back together, like a handful of rocks tossed back to Earth?
Sandage and others sought to answer that question by looking at how the universe had been expanding in the deep past. He concluded that it was slowing down and would one day fall back together in a Big Crunch. That was about as momentous a prediction as any scientist could ever make.
But the answer depended on the presumption that certain galaxies — egg-shaped agglomerations known as giant ellipticals, which he was using as cosmic distance markers — were so-called standard candles, not changing much over time.
Tinsley’s work suggested, however, that these galaxies were not so constant — that they could dim with age as the stars inside them evolved.
Such effects, if true, would undermine Sandage’s method and could tip the answer of the fate of the universe to that of expanding forever, existence being a one-way trip into the eternal night.
Her dissertation was published — Sandage ignored it — and she got her Ph.D. in 1968. At the same time, she and her husband adopted a boy, Alan, and then later a girl, Teresa. While in Dallas, raising the children, she got involved in Planned Parenthood and Zero Population Growth.
Meanwhile, by dint of scientific conferences and visits to places like Mount Wilson and Palomar and the University of Maryland, Tinsley continued to pursue her vision of galaxies and cosmology.
In 1972 she and three young colleagues — James Gunn and J. Richard Gott of Princeton and David Schramm of the University of Texas at the time — set out to summarize what they thought was growing evidence that the universe would expand forever.
“We were sort of young Turks wanting to upset the establishment,” Schramm, who died in 1997, said in an interview in 1986.
“Beatrice was the glue,” recalled Gunn, who said that she had done most of the writing for the paper, titled “An Unbound Universe?” The paper had a saucy tone, far from the austere formality that had characterized astronomical pronouncements before.
“Desist from thrusting out reasoning from your mind because of its disconcerting novelty,” the paper began, quoting the Roman poet and philosopher Lucretius. “For the mind wants to discover by reasoning what exists in the infinity of space that lies out there beyond the ramparts of this world,” it went on. “Here then is my first point. In all dimensions alike, on this side or that, upward or downward through the universe, there is no end.”
In other words, the universe would expand forever; there would be no Big Crunch, no chance of a second act for the Big Bang. After the paper was rejected by the journal Nature, it was published in The Astrophysical Journal in 1974.
A year later Sandage reached a similar conclusion, that the universe was not slowing down enough to ever collapse again. So much for the idea (a sentimental favorite of many astronomers) of a cyclic universe going from Big Bang to Big Crunch, like a beating heart. “The universe has only happened once,” Sandage wrote.
In the years before cancer struck her down in 1981, Tinsley became known as the world’s leading expert on the aging and evolution of galaxies.
Walter Oleksy/Alamy
(Further observations a quarter of a century later, using distant exploding stars instead of galaxies as milestones, were to show that the expansion of the universe was in fact speeding up, under the influence of what astronomers call dark energy. Tinsley had been right “with a vengeance,” Larson said.)
That same year, 1975, Tinsley was awarded the Annie Jump Cannon Award, given by the American Association of University Women for outstanding postdoctoral research.
But despite her rising prominence, she couldn’t find a job in Texas. She complained to her father that she felt “rejected and undervalued intellectually.”
Reluctantly, she expanded her search and took a job at Yale, drawn by the chance to work with Larson. She divorced Brian Tinsley, from whom she had grown distant, and gave up custody of the children, leaving on Christmas, Larson said.
It was a choice she later agonized over. When her cancer appeared, Larson said, she wondered if it was nature’s retribution for her being a bad mother.
Larson said she had tried to make up for her absence by inviting the children to visit New Haven regularly and taking them on vacation trips.
But it hurt, said her daughter, Teresa Tinsley, who now lives in Dallas. (Tinsley’s son, Alan, lives in Phoenix.)
“She was given an ultimatum that in my opinion was unfair: Choose family or a career,” Teresa Tinsley wrote in an email. “But that is how it was back in those days — women were supposed to be homemakers. I am proud that she stood her ground and followed her career.”
She added, “She followed her dream — a dream created when she was a very young lady, her dream to be a scientist.”
At Yale, Tinsley was the first female astronomy professor. Her position, as she wrote to her father, gave her “a sense of hope and power over the future that has escaped me for years.”
In 1977 she organized and hosted a symposium that brought together the world’s experts on the evolution of stars and galaxies. The transcribed proceedings, which she and Larson edited, have become a classic reference for researchers.
But she did not have long to enjoy her recognition. A year later she discovered that a lump on her leg was melanoma.
In 1979 she brought Teresa, who was then 11, to New Haven for whatever time was left. Her daughter recalled playing after school in the halls of the astronomy department, and her mother helping her with her homework in the Yale Infirmary. Near the end, Tinsley wrote a poem:
Let me be like Bach, creating fugues Till suddenly the pen will move no more.
Let all my themes within — of ancient light
Of origins and change and human worth —
Let all their melodies still intertwine,
Evolve and merge with growing unity,
Ever without fading
Ever without a final chord … Till suddenly my mind can hear no more.
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