Life of astronomer Nancy Grace Roman (May 16, 1925 – December 25, 2018)

Nancy Grace Roman (May 16, 1925 – December 25, 2018) not only laid the foundation for our understanding of how galaxies grow, but she also founded NASA’s space astronomy program, becoming the mother of Hubble.

Roman’s love for the stars was evident from an early age and when he was just 10 he started an astronomy club for his friends.

However, when she told her guidance counselor that she wanted to be a professional astronomer, she was asked, “What woman would take up math instead of Latin?”

Ignoring this discouragement, he earned his BA from Swarthmore University before transferring to the University of Chicago Yerkes Observatory for his Ph.D.

Here he studied the motions of stars that formed in the same Plow cluster, but that had drifted apart over time.

Later, Roman extended this search to all sun-like stars visible to the naked eye and soon noticed that where the stars orbit in the Milky Way was related to their metallicity.

Metals (aka anything heavier than helium in astronomy) only form inside stars, so if a star contains a lot of metal it must have been born after several generations of previous stars had already produced them.

Younger metal-rich stars tended to move in circular orbits near the center of our Galaxy, while older metal-poor stars were farther away.

This connection was the first clue to understanding how the Milky Way grows over time, providing the basis for modern studies of galactic evolution.

His work also developed a method for measuring stellar metallicities by comparing their luminosities at blue and ultraviolet wavelengths, which is still used today.

Work at NASA

Despite these important discoveries, Yerkes Observatory refused to allow a woman a permanent position, so in 1954 Roman moved to the Naval Research Laboratory in Washington DC to work in the emerging field of radio astronomy.

Here she mapped the Milky Way into new wavelengths, became head of microwave spectroscopy, and was consulted on the Vanguard satellite program.

With radio astronomy still in its infancy, the instrumentation was inadequate for Roman needs and she did not want to retrain as an electrical engineer to build her own.

So in 1959 he moved to the National Aeronautics and Space Administration, NASA, as head of observational astronomy, just a year after the agency was founded.

This new role effectively ended her research, but with it, Roman became the first woman to hold an executive position at NASA, giving her overall responsibility for the growing agencies’ space observers.

Initially, many ground-based astronomers were stubbornly against the use of remote satellites, but Roman worked tirelessly to convince them of the benefits of observing above the Earth’s atmosphere.

Believing that the best way for the United States to reap these benefits was for NASA to oversee all major space observatories, Roman initially had the sole say in deciding which projects would be funded.

Although many of his colleagues advocated for NASA to build a large space telescope, he dismissed the plans as premature, choosing instead to fund a series of smaller satellite observatories.

Only in 1968, after a decade of success proving NASA’s capabilities, did Roman return to the idea of ​​a larger mission, though it took another three years of feasibility studies and funding before she could finally found the Large Telescope Steering Group.

More so

It would take dozens of institutions 20 years to complete the project, but the telescope launched in 1990, renamed the Hubble Space Telescope.

Though Roman was heavily involved in overseeing the mammoth projects in the early years, she retired from NASA in 1979 as head of astronomy, occasionally returning as a consultant.

She continued outreach work as part of her lifelong mission to support the inclusion of women in astronomy.

His vision and many legacies, both scientific and cultural, continue to shape astronomy to this day.

Roman telescope Nancy Grace

While he may not be a household name at the moment, Roman will soon be much better known, as an infrared telescope named in his honor is set to launch in 2027.

The Nancy Grace Roman Space Telescope will have a 2.4m mirror the same size as that of the Hubble Space Telescope, but its Wide Field Instrument will have a field of view 100 times that of the Hubble infrared camera.

It will use this huge view to create a 3D map of distant galaxies, galaxy clusters and supernovae to measure how matter is distributed in the Universe.

These observations will complement those of ESA’s Euclid mission in the quest to track down dark energy, the mysterious force that appears to accelerate the expansion of the Universe.

The telescope will even be able to map otherwise invisible dark matter using a method called microlensing.

When light from a distant galaxy passes through another massive object, its path bends slightly, becoming stretched and distorted.

These distortions can then be analyzed to reveal how matter is distributed throughout the cosmos.

Lensing also occurs when a planet passes in front of its host star, and the telescope will monitor 100 million stars in hopes of spotting the brightness of a fluctuating star as an exoplanet passes in front.

Most excitingly, this technique should be able to reveal small rocky worlds in habitable orbits, similar to our Earth.

This article originally appeared in the July 2023 issue of BBC Sky at Night magazine.