Astronomy Book Review on Miss Henrietta Leavitt’s Stars

Astronomy Book Review on Miss Henrietta Leavitt’s Stars


Miss Henrietta Leavitt, an American astronomer made a discovery that was to become one of the cornerstones of modern astronomical physics. She determined the relationship between luminosity and period of fluctuation for a class of pulsing variable stars thereby coming up with the Cepheid variable which was named after the prototype star delta Cephei in the constellation Cepheus. Her discovery led to a breakthrough that has enabled astronomers to measure the distance between earth and faraway galaxies. While studying the stars using the photographic plates, there was no standard for ascertaining the magnitudes of the stars. She therefore decided to come up with her own system. In 1892, she graduated from Radcliffe College before spending several years as an advanced student and volunteer research at the Harvard Observatory, both in travel and teaching until she was made a permanent member of the Harvard Observatory team.

Work and discoveries

Henrietta Leavitt worked as a “computer” at Harvard college observatory which was under the directorship of Edward Pickering. Her work as a human computer entailed examining photographic plates so as to make photometric measurements of variable stars. In 1902, she discovered a type of bright variable star pulsated with a period directly proportional to its true brightness (Johnson 3). Upon further studying the variable stars in the Large Magellanic Cloud which is a satellite galaxy of the Milky Way, she noted that bright stars had longer pulsating periods. She used the period of these variable stars to determine their true brightness by calibrating them with similar stars closer to our solar system since roughly all the stars were the same distance from earth. Through her work, she changed the paradigm of distance determination by providing a reliable ruler with which to measure the universe.

One of the most surprising accomplishments of Miss Henrietta Leavitt was the discovery of 1777 variable stars in the Magellanic Clouds (Johnson 5). Photographs of long exposure made at Arequipa with the 24-inch Bruce refractor facilitated the results. Some of these plates had exposures of from two to four hours and showed very faint stars among which almost all the variables are found. Altogether, Miss Henrietta found four new stars, about 2400 variable stars, various asteroids and other objects (Johnson 11). Leavitt barely got credit for her work due to the fact that women ranked under the stewardship of their male counterparts in the field of science. For her works, Leavitt could have earned a Nobel price but she died of cancer four years before she was even considered for the award by Swedish mathematician Gosta Mittag-Leffler. Nobel Prize is not awarded after demise of the person (Johnson 46). Her discovery of the Cepheid variable revolutionized how distance could be measured using Cepheids as standard candles. Scientists incorporated Miss Henrietta Leavitt’s work and used it as a yard stick to help determine the existence of other galaxies beyond the Milky Way. Ejnar Hertzsprung determined the distance of several Cepheids in the Milky Way and this measurement enabled the distance to any Cepheid to be accurately determined (Johnson 9). Edwin Hubble, an American astronomer used Henrietta’s’ information to help him understand the distance to the nearest large galaxy to earth known as the Andromeda Galaxy or M31 (Johnson 19). He discovered that the Cepheid was much further away than actually thought of and thus the nebulae was not a gaseous cloud inside our galaxy but a galaxy of stars just like the Milky Way. Additionally, by observing redshifts in the light wavelengths emitted by the galaxies, he noted that galaxies were moving away from one another at a rate constant to the distance between them. This is known as the Hubble’s Law. Edwin Hubble determined that there were other galaxies like our own in the universe (Johnson 13).

Challenges faced

Being a “computer” was predominantly a man’s work. Levitt completed a Bachelor of Arts degree but she was rewarded a certificate since she was of a female gender. In the early 1900s, women were not allowed to use the telescope and she earned a low salary equivalent to that of a servant (Johnson 30). The field of astronomy was mainly dominated by males with women being relegated on the side lines. Edward Pickering, the director of Harvard Observatory took all the credit due to his boss status. Henrietta got a job at the Harvard college observatory in 1893 as a “computer” (Johnson 26). Her workplace was a tiny office alongside of other of her female colleagues who were relegated to the same working conditions. She contracted an illness while back at Radcliffe College which rendered her increasingly deaf. She received little recognition for her work.

Miss Henrietta Leavitt paved the way for more research and discoveries. The dedication and effort she put reflected in her work. She was a computer long before modern computers existed. Indeed, her discoveries showcased her dedication and commitment to making a positive difference. In addition, Leavitt’s work on astronomy broke the barrier on women being less equipped and able to make significant changes in the field of Science. Indeed, Levitt’s discoveries have revolutionized how we view the galaxy. Her innovation of the Cepheid variable has also led to massive developments as scientists are today able to measure large cosmic distances. As opposed to the ancient norm where women were given the backseat, women are today at the forefront on making more discoveries that are aligned to the current world’s developments.


Johnson, George. Miss Leavitt’s Stars: The Untold Story of the Woman Who Discovered How to Measure the Universe. New York: Norton, 2005. Print.