Look Up! by Robert Burleigh

Over one hundred years ago, a woman astronomer named Henrietta Swan Leavitt made a remarkable discovery that changed forever how astronomers viewed the universe. For her breakthrough, Henrietta Leavitt received absolutely no recognition. It was a discovery that other astronomers such as Ejinar Hertzsprung and Edwin Hubble would use in their own research. In fact, Hubble never credited Leavitt's previous work as a significant factor in his own research. Recognition for Leavitt's outstanding contributions to astronomy would come after her death in 1921. In Look Up!, Robert Burleigh tells Henrietta Leavitt's story for a new generation of young girls, inspiring them to follow their interest in science.

Henrietta Swan Leavitt was born in Massachusetts on July 14, 1868. She was an intelligent, hard-working student, attending Oberlin College and then the Society for Collegiate Instruction of Women, which was eventually renamed Radcliffe College. At Radcliffe, Henrietta received an intensive education that if she were a man, would have led to a career in academia. However, in the late 19th century, such a possibility was not open to young, intelligent, well educated women.

In 1892, in her senior year at Radcliffe, Henrietta discovered astronomy. In 1893, after graduation, Henrietta  joined the Harvard College Observatory as an unpaid volunteer where she became a "Harvard computer" under the direction of astronomer Edward Pickering. Despite her rigorous education this was the only type of job available to educated young women. Henrietta was forced to leave due to a serious illness that left her profoundly deaf. She eventually returned to the Observatory in 1902. Her job, at a pay of 30 cents, was to catalogue the brightness of stars.

The 'Harvard computers' was a group of over eighty women who came to be collectively known in scientific circles as 'Pickering's Harem', a somewhat demeaning reference. The Harvard Computers included many brilliant women who would come to make outstanding contributions to the field of astronomy. These included Williamina Fleming who discovered the Horsehead Nebula in 1888, Annie Jump Cannon who helped catalogue over one million stars, Margaret Harwood who was later to become the first woman director of the Maria Mitchell Observatory, and Cecilia Payne who discovered that the Sun was comprised mainly of hydrogen.

Leavitt's job was to look at variable stars, so named because their luminosity changes over time in a regular pattern known as a period.  She was working with Cepheid stars in the Magellanic Clouds (two dwarf galaxies near the Milky Way). Henrietta discovered by mathematical calculation and detailed observation of these Cepheid variable stars that there is a direct correlation between how bright a star is (called the star's magnitude) and the length of time it goes from dim to peak brightness (its period of luminosity). In other words, brighter stars had larger periods of luminosity. This became known at the period-luminosity relationship or Leavitt's Law. Since the Cepheid stars are all about the same distance from Earth, their period is directly related to the magnitude, not distance. Using magnitude, one can determine their distance from Earth. Henrietta did this, not by telescope which she was not, as a woman, allowed to use, but by examining photographic plates. She published her results in 1912 in the form of a chart that allowed astronomers to determine very accurately the distance of stars from Earth and the distance between stars. Astronomers would even be able to attempt to calculate how large the universe is.

Unfortunately Henrietta Leavitt never received the recognition she deserved for this discovery which immediately set off a chain of amazing discoveries in the field of astronomy. At the time, the universe was believed to contain only the Milky Way galaxy but working from Henrietta's discovery, astronomers quickly learned the vastness of the cosmos. She was under consideration to be nominated for the Nobel Prize in 1925 but this was too little too late. She had passed away four years earlier. Even one hundred years after her amazing discovery, little has been done to commemorate her outstanding contribution to astronomy.

Discussion

Look Up! tells Henrietta Leavitt's story for young readers, capturing many of the crucial points of her life. Burleigh does a good job of attempting to explain exactly what Henrietta discovered and its significance to the discipline of astronomy. Raul Colon's exquisite illustrations are "rendered in watercolors, Prismacolor pencils and lithograph pencils on Arches paper."  They add a lovely visual dimension to this beautiful picture book, as they should, enhancing Burleigh's simple text.

Look Up! is a must-have book for any library or school wishing to promote the hidden accomplishments of women scientists to young girl readers.  Burleigh has included an Afterword that tells a bit about Henrietta Leavitt, a Glossary of Terms, and a list of resources, both online and print for learning more about the stars, telescopes, planets and the solar system. Although there is a small portrait of Henrietta Leavitt , it would have been wonderful to see more photographs of her included in the Afterword.

Image credit: https://scientificwomen.net/women/leavitt-henrietta-55

Book Details:

Look Up! by Robert Burleigh
New York: Simon & Schuster Books For Young Readers 2013