Henrietta Swan Leavitt
Recently, I got interested in learning about galaxies and how they are keeping an order. It led me to search for Particle Physics women astronomers. People usually don’t talk about women astronomers. I doubted that I could find any. To my surprise, my YouTube search found a string of women astronomers.
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I gathered information about the forgotten women astronomer heroines who contributed considerably to this field. This collection of facts I obtained from a lecture by Professor Dr. Jo Dunkley from Princeton University, professor of physics and astro-physical sciences who gave the lecture on NIT TV and SBS. Dr. Dunkley was a part of a team for Knapp’s NASA’s WMAP Space satellite. Now, she works on the Atacama cosmology telescope at Simons observatory and it is the largest synoptics survey telescope. She received many awards, the Maxwell medal, the Fowler prize for astronomy and the Royal Society’s Rosalind Franklin award and the Philip Leverhulme prize. She also gave an interview in Australia.
Dr.Saroja Ilangovan M.D.,
Neuropathologist,
United States of America
Dr. Dunkley gives a lot of credit to humans involved in Astronomy, looking at the stars in the sky for millennia. She appreciates the sky in the southern hemisphere, better than the north. She also pointed out the prejudice about gender bias in recognizing famous women astronomers and physicists, even though they were very credible female astronomers. She found many more women astronomers during her research of the history of astronomy and wrote a book about them.
During her research, she came to know about a group of women called Harvard computers, who worked at the Harvard college observatory in the United States at the turn of the century. They were brought into the observatory by a visionary scientist called Edward Pickering. He brought them in because he ran out of research money. These male astronomers figured that employing women would be economical because women were underpaid those days. The male astronomers would be operating large telescopes and taking pictures of the sky in cold weather and tracking the stars which was physically challenging. The women astronomers were studying, classifying and understanding the plentiful range of stars in the night sky. These women came up with the classification of the stars which is still in use today.
These women astronomers were performing mundane tasks like tracking the brightness and colors of thousands of stars. They also made great discoveries. One of these great women was Henrietta Swan Leavitt. She went to Radcliffe College which was attached to Harvard. At that time, women could not get a degree, but they could study in college. She worked at the Harvard University observatory. She painstakingly tracked a unique group of stars which pulsated with brightness and she tracked them over the weeks and months. The brightness of the stars was alternating with brighter and fainter intensity. Her incredible work has become Leavitt’s Law. This is the key Edwin Hubble used in his work to become more famous. He used Henrietta’s discovery to make his own discovery of finding galaxies of stars beyond our own Milky Way.
The Milky Way is a disc of hundred billion stars. A century ago, no one thought there was anything more than that. But using Leavitt’s law, Edwin Hubble looked out into space and saw smudges of light which are other galaxies beyond our own. Using this law, the astronomers deduced that the universe is growing and that it began as a big bang. All became possible because of Henrietta Swan Leavitt’s discovery and Leavitt’s law. Yes, she is one of the great heroines who deserves a lot more great credit.
Since then we have found many more galaxies, such as swirling disc galaxies, clusters of galaxies, etc. totaling about 1 trillion galaxies in the universe that we can now observe. Each galaxy has about a hundred billion stars. A century ago, we didn’t know why the stars are bright, why they shine at night while our planet does not. Where do they get energy and what are they made of? Earlier, the astronomers thought that the stars are of similar composition as the earth, and that carbon, iron, and some other elements make us. Stars may have the same composition but they have something inside them that is producing light. Many people tried to figure it out.
The person who figured it out was Cecilia Payne-Gaposchkin. She was not well known. She was British and she did her undergraduate study at Cambridge University in the UK. While she was there, she was captivated by a lecture given by Professor Arthur Eddington about an expedition he took to watch the eclipse of the sun which was used to prove that Einstein’s law of general relativity was correct. Einstein’s new theory of how gravity works was proved right. This lecture helped her to decide her future profession. In the 1920s, Payne realized that she had no future in the UK as a professional astronomer because she was a woman, but she knew about the women astronomers in Harvard.
She sailed to the other Cambridge in the USA to join this women’s group in Harvard in the 1920s. Eventually she became the first woman to earn a Ph.D in Harvard. While she was there, her investigations solved the puzzle about the energy in the stars, which are balls of hydrogen and helium gas, except for small subtle differences that were their nature. This was the inference from her analysis of data that was available at that time. This was also her Ph.D thesis. Some of the astronomers were skeptical and one of the leading astronomers at that time, Henry Norris Russell at Princeton University discouraged publication of her thesis. However, in a few years, her thesis turned out to be right and she became the first professor of astronomy and eventually she became the Chair of the Astronomy department in Harvard.
To be continued….
