Silent Sky introduces a young Henrietta leaving her Puritan family with the help of her sister Margaret, who stays home and leads the traditional life of a faithful mother and wife while Henrietta heads to Harvard to study the stars. Henrietta meets Peter, a young astronomer who is supposedly her superior, and her fellow “computers”: Willamina - a housewife-turned-astronomer, and Annie - a ballsy academic who is “one of the men,” even if the men wouldn’t admit it.

As Henrietta secretly labors at nights getting closer to her discovery, she also gets closer to Peter and farther from Margaret, straining her relationship with her family. Just when Peter admits his adoration for Henrietta and spontaneously invites her on a world cruise to see an eclipse, Margaret’s reveals that Henrietta’s father has died and she must return home.

But it is Margaret’s musical ability that ignites Henrietta’s mathematical genius that leads her to finally see (or hear) the music in her numbers. Music and math (not Peter and world travel) combine for her greatest discovery: the Period-Luminosity Relation. Simply put, Henrietta discovers that the blinking stars she’s tracking blink according to their size - the brighter the stars the longer they take to blink. Once she knows how big the stars really are, she can measure their distance and thus the distance to the end of our galaxy and beyond.

As Henrietta’s reputation and career at back at Harvard begin to grow, so does her debilitating ovarian cancer.  Her sickness leads her back home to Margaret, where she must experience the world through music, math, and the stars from her backyard. Her fellow computers tell her that her work is already used to measure the galaxy... and soon the universe. Annie is now a firebrand feminist protesting for women's suffrage. "If women can organize the sky we can organize the vote."

But Henrietta doesn't see the vote or the full implementation of her work. As the world continues,  and her work makes the careers of many many men - Henrietta’s gets a seat in the wide and silent sky.


Henrietta Leavitt - 30, brilliant, meticulous, dedicated

Margaret Leavitt - 30, home-body, creative, sweet, sister

Peter Hampstead – 30, the head astronomer’s apprentice… and the man

Annie Cannon – 40, the leader, tense and sure

Willamina Flemming – 50, smart as a whip, Scottish stock, and fun

"Pickering's Harem," so-called, for the group of women computers at the Harvard College Observatory, who worked for the astronomer Edward Charles Pickering. The group included Harvard computer and astronomer Henrietta Swan Leavitt (1868–1921), Annie Jump Cannon (1863–1941), Williamina Fleming (1857–1911), and Antonia Maury (1866–1952). Photograph courtesy of the Grasslands Observatory.



Leavitt Home, Lancaster Massachusetts

The Harvard Observatory 2nd floor offices, 1900

Ocean Liner at night

The Viewing Room of Harvard Observatory Telescope

File:Great Refractor.jpg

Astronomical Research

Cepheid Variable Stars... (longer piece here)

Henrietta and Cepheids

Certain stars that have used up their main supply of hydrogen fuel are unstable and pulsate. Their brightness doubles from dimest to brightest.
Cepheid variables have longer periods that RR Lyrae stars, from one day up to about 50 days. Their brightness also doubles from dimest to brightest.

Cepheids are important beyond their intrinsic interest as pulsating stars. Astronomers have found that there is a relation between the period of a Cepheid and its luminosity.

This enables astronomers to determine distances:
  • Find the period.
  • This gives the luminosity.
  • Measure the apparent brightness.
  • Determine the distance from the luminosity and brightness.


Actual 1912 Harvard Publication of P-L Relationship -

Henrietta's work and Hertzsprung's


In 1924 Edwin Hubble discovered Cepheid variables in the Andromeda galaxy. This settled the Island Universe debate, concerning the question of whether the Milky Way and the Universe were synonymous, or was the Milky Way merely one in a plethora of galaxies that constitutes the Universe.[7]

Combining his calculations based on Cepheids of distances of galaxies with Vesto Slipher's measurements of the speed at which the galaxies recede from us, in 1929 Hubble and Milton L. Humason formulated what is now known as Hubble's law, which established that the Universe is expanding.

Cepheid variables have been used in a variety of ways, including placing cosmological constraints on the expansion of the Universe through the determination of distances to galaxies.[8] They have also been used to measure many characteristics of our galaxy and our relationship to it, for example: to determine the Sun's height above the galactic plane, to establish the distance to the galactic center, and to interpret the local galactic spiral structure.[9]

Hubble and Cepheids

Images from the Harvard Star Plate archives, including the Rho Ophiuchus nebula (1948), left, the constellation Sagittarius (1943), center, and the Large Magellanic Cloud (1900), right. (NYT picture)


When I Heard the Learn'd Astronomer
by Walt Whitman, 1892

When I heard the learn’d astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts and the diagrams, to add, divide, and measure them,
When I sitting heard the astronomer where he lectured with much applause in the lecture-room,
How soon, unaccountable, I became tired and sick,
Till rising and gliding out I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.


Our Place in The Universe - Sagan

Annie's Sash!



Henrietta Swan Leavitt (July 4, 1868 – December 12, 1921) was an American astronomer. A graduate of Radcliffe College, Leavitt went to work in 1893 at the Harvard College Observatory in a menial capacity as a "computer", assigned to count images on photographic plates. Study of the plates led Leavitt to propound a groundbreaking theory, worked out while she labored as a $10.50-a-week assistant, that was the basis for the pivotal work of astronomer Edwin Hubble. Leavitt's discovery of the period-luminosity relation of Cepheid variables radically changed the theory of modern astronomy, an accomplishment for which she received almost no recognition during her lifetime.

During her career, she discovered over 2,400 variable stars, roughly half the known total in that era.
Even though Leavitt worked sporadically at Harvard due to health problems and family obligations, she was made head of stellar photometry in 1921 by new director Harlow Shapley. However, by the end of the year Leavitt passed away, suffering from cancer. However, unaware of her death, the Swedish mathematician Gosta mittag Leffler considered nominating her for the 1926 Nobel Prize in Physics and wrote to Shapley requesting more information, but the Nobel Prize is not awarded posthumously.

Lunar Crater Leavitt is named for her.
(more at Wikipedia)

About Annie and Henrietta's possible deafness -
ISOTOPE:  Music of the Spheres


George Johnson's biography...

Miss Leavitt's Stars:
The Untold Story of the Woman who Discovered how to Measure the Universe

 free on GoogleBooks

NPR interview - here

 - NY Times Review (fabulous article)
'Miss Leavitt's Stars': The Female Computer

- LA Times Review - great article

- A Trip Back in Time and Space - G Johnson, NYT

(Article about Harvard Observatory's star plate collection and Henrietta's work)


Annie Jump Cannon

Annie Jump Cannon (December 11, 1863 – April 13, 1941) was an American astronomer whose cataloging work was instrumental in the development of contemporary stellar classification. With Edward C. Pickering, she is credited with the creation of the Harvard Classification Scheme, which was the first serious attempt to organize and classify stars based on their temperatures. Annie never married but was happy to be an aunt to her brother's

Not long after the work on the Draper Catalog began, a disagreement developed as to how to classify the stars. Antonia Maury, who was also Henry Draper's niece, insisted on a complex classification system while Williamina Fleming, who was overseeing the project for Pickering, wanted a much more simple, straightforward approach. Annie Jump Cannon negotiated a compromise. She started by examining the bright southern hemisphere stars. To these stars she applied a third system, a division of stars into the spectral classes O, B, A, F, G, K, M. She gave her system a mnemonic of "Oh Be a Fine Girl and Kiss Me."[citation needed]

At this time the women astronomers doing this groundbreaking work at Harvard Observatory were paid 25 cents a day. The secretaries at Harvard were paid more.

Annie’s work was “theory laced” but simplified. How she could see the stars or stellar spectra was extraordinary. Her Henry Draper Catalogue listed nearly 230,000 stars was valued as the work of a single observer. Annie also published many other catalogues of variable stars, including 300 that she discovered. Her career lasted more than 40 years in which time women won acceptance into science.

Annie Jump Cannon died April 13, 1941 after receiving a regular Harvard appointment as the William C. Bond Astronomer. She also received the Henry Draper Medal, which only one other female has won, Martha P. Haynes (who shared it with a male colleague).

Late in life Annie said, “In our troubled days it is good to have something outside our planet, something fine and distant for comfort.”




1890: American Woman Suffrage Association and National Woman Suffrage Association merge into the National American Woman Suffrage Association.

January 25, 1887: The United States Senate voted on woman suffrage for the first time -- and also for the last time in 25 years.

1893 - Henrietta begins work at Harvard College Observatory

- Henrietta first published her data - noting a pattern in variable stars

May 4, 1912: Women marched up Fifth Avenue in New York City, demanding the vote.

1912 - Henrietta publishes a full paper documenting her Period -Luminosity  relationship

1913 - Ejnar Hertzsprung uses Henriett'a fining to measure distance to cepheids within the Milky Way.

April 1917 - The United States government declares war against Germany - WW1

June 1917: Arrests began of Suffrage pickets at the White House.

January 10, 1918: House of Representatives passed the Anthony Amendment but the Senate failed to pass it.

Nov 1918 - WW1 ends

May 21, 1919: United States House of Representatives passed the Anthony Amendment again.

June 4, 1919: United States Senate approved the Anthony Amendment.

1920 - Henrietta made head of Stella Photometry

August 26, 1920 -  United States Secretary of State signed the Anthony (19th) Amendment into law.
Dec 12th, 1921 - Henrietta dies of ovarian cancer

1923-24 - Edwin Hubble measures Cepheids in Andromeda Galaxy proving that the universe is far bigg than the Milky Way

1926 - Unaware of her death four years prior, the Swedish mathematician Gösta Mittag-Leffler considered nominating her for the 1926 Nobel prize in physics.

From the Harvard Observatory Plate Collection:
Plate b26816 of Large Magellenic Cloud taken on December 18, 1900 from Arequipa, Peru, with the 8 inch Bach Doublet, Voigtlander, reworked by Clark. The exposure was 60 minutes centered on 5h09m47s R.A. and -67d22m51s Declination. We have not removed the annotations made on the back of the plate because this plate is referenced in the Henrietta Leavitt logbooks made during her research on Cepheid stars.

Henrietta become gradually more and more deaf starting in her college years at Radcliff. She would take out her hearing device when working to better concentrate.

Portable Acousticon in use

Woman using the Portable Acousticon, as illustrated in: Evan Yellon’s Surdus in search of his hearing: an exposure of aural quacks and a guide to genuine treatments and remedies electrical aids, lip-reading and employments for the deaf etc., etc. London: Celtic Press, 1906 (p. 48). This small type Acousticon was intended to be carried about by the user, with the receiver attached to some part of the clothing, the battery into a pocket or handbag and the ear-piece carried in the hand or attached to a lorgnette handle.


Rhapsody: musical variational pieces inspired by extroverted romantic notions.

A rhapsody in music is a one-movement work that is episodic yet integrated, free-flowing in structure, featuring a range of highly contrasted moods, colour and tonality. An air of spontaneous inspiration and a sense of improvisation make it freer in form than a set of variations. Sergei Rachmaninoff's set of variations on a theme by Niccolò Paganini are so free in structure that the composer called them a Rhapsody on a Theme of Paganini.


Flyspanker plates from 1917, which were used to compare celestial brightness. (NYT picture - below)

Almost as important as the plates are the handwritten logbooks, which researchers are working to transcribe. (Below - NYT)

Suffrage Pics

1920 Suffrage Rally

1912 Suffrage Parade