Shop Windows to the Universe

Check out the fun Earth science related bumper stickers in our online store! Express yourself!
Harvard University Clock Tower - the school at which Leavitt did her research.
Click on image for full size
Courtesy of Corel Photography

Henrietta Swan Leavitt

Henrietta Swan Leavitt was born in Lancaster, Massachusetts in 1868. She became interested in science and astronomy in college. Unfortunately, she became quite ill after her graduation from college. She spent several years at home recovering from the illness which left her almost completely deaf. But she hadn't forgotten astronomy!

She volunteered at Harvard College's Observatory, until she was hired permanently at the salary of 30 cents an hour. At the observatory, she observed stars and watched how variable stars changed in brightness over time. Henrietta is known for her 1904 discovery of a type of variable stars named cepheid variables. Cepheid variables are stars that go through cycles of brightness and darkness. Henrietta found that when observing a cepheid variable in another galaxy, she could relate the length of the brightness cycle to the size of the star. With this discovery, she was able to determine the distances between stars and the Earth. Cepheid variables are referred to as "astronomical yardsticks" as they make it easier to measure distances within the universe.

She died of cancer in 1921 at age fifty-three. Her name was given to a crater of the moon to honor deaf men and women who have worked as astronomers and scientists.

Shop Windows to the Universe Science Store!

Our online store includes books on science education, ranging from evolution, classroom research, and the need for science and math literacy!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

A Trip to the Observatory

Have you ever wondered what it would be like to take a trip to an observatory to use the telescope? In February 2006, astronomer Travis Metcalfe was granted 7 nights of observing time on one of the telescopes...more

A Trip to the Observatory - Transcript

I'm Travis Metcalfe, an astronomer at the National Center for Atmospheric Research in Boulder, Colorado. I made this short video for anyone who's ever wondered what it's like to take a trip to the observatory...more

Correlations in Science

In conducting their research, scientists often want to know if two sets of data (variables) are related to each other. For instance, you might wonder if the amount of time a student spends reading the...more

Hipparchus

Hipparchus was a Greek astronomer who lived between 190-120 B.C. He created the first accurate star map and kept a catalogue of over 850 stars with their relative magnitudes. The system of epicycles describing...more

James Adamson

James Adamson is an American astronaut who was born in New York in 1946. He attended military school from 1965-1969 and studied engineering. From 1969-1980 he stayed in the Army as an aviator and professor....more

Tom Akers

Tom Akers is an American astronaut who was born on May 20, 1951 in Missouri. Before he was an astronaut, Akers was a park ranger, teacher, and Air Force pilot. He has flown 25 different types of aircraft....more

Joseph Allen

Joseph Allen is an American astronaut who was born on June 27, 1937 in Indiana. Before he became an astronaut, Allen was a physicist who taught at the University of Washington. Allen became an astronaut...more

Jim Bagian

Jim Bagian is an American astronaut who was born on February 22, 1952 in Pennsylvania. Before he became an astronaut, Bagian was an engineer and a medical doctor. Bagian became an astronaut in 1980. He...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF