Images from the Hubble telescope, measurements of distances to distant stars, radio astronomy observations – all of this would not have been possible without the discoveries made by the characters in this story.
Henrietta Swan Leavitt
Through her painstaking research on the variables of vision, Henrietta Swan Leavitt proposed a method for measuring distances to distant bodies.
Leavitt’s discovery led to modern astronomy’s understanding of the structure and size of the Universe. Her groundbreaking research made possible the achievements of Edwin Hubble, who found the distance to the nearest galaxy and established that the Universe is expanding. The fact is that until the 1920s, astronomers believed that the Universe was limited to our Galaxy.
But in 1923-1924, Edwin Hubble, having measured the distances to several cepheids in the Andromeda Nebula galaxy using a method developed by Henrietta Swan Leavitt, realized that they were much further away and that the Andromeda Nebula was a separate galaxy. This star system was outside the Milky Way. The distance he calculated was 900,000 light years.
Born in 1868, Henrietta Swan Leavitt was educated at Oberlin College and Harvard’s Radcliffe College. After graduation, she worked at the Harvard Observatory, where she became an assistant to astronomy professor Edward Charles Pickering. Together with a dozen other women, she analyzed photographic plates, cataloging stars and noting how their brightness changed.
Leavitt and her colleagues were jokingly called “Pickering’s harem” by Harvard scientists. While working on photographic plates of images of the Magellanic Clouds taken at the Arequipa Observatory in Peru, she discovered 2,400 aurorae. She published her first catalog of 1777 aurorae in 1908.
The study of cepheids led her to discover the relationship between the period of change in the luminosity and luminosity of a star, which later became a method by which astronomers were able to measure the distances to luminaries in our Galaxy and beyond. Leavitt noticed that the luminosity of cepheids varies with a clear periodicity, which prompted her to create a distance scale using the ratio of the period of change in their luminosity and luminosity, which allowed scientists to calculate distances to distant stars to which stellar parallax cannot be applied due to the great distances. This ratio is named in her honor, Leavitt’s Law.
Together with Pickering, she developed a standard for photographic measurements of the luminosity of luminaries, which was internationally recognized in 1913 and was called the Harvard Standard.
A year after Leavitt reported her results, Ejnar Hertzsprung determined the distance to several cepheids in the Milky Way and confirmed that this calibration can accurately determine the distances to any star.
After working at the Harvard University Observatory for the rest of her life, Henrietta Swan Leavitt died in 1921. Edwin Hubble often said that Leavitt deserved the Nobel Prize for her work. The mathematician Mittag-Leffler, a member of the Swedish Academy of Sciences, tried to nominate her for the prize in 1925, but learned that she had died three years earlier. The asteroid (5383) Leavitt and a crater on the Moon are named after the scientist.
Ruby Violet Payne-Scott
Ruby Violet Payne Scott: a pioneer of radio physics and radio astronomy, the first female radio astronomer. She noted that the Sun emits both light and powerful streams of electromagnetic waves that are invisible but can be heard, and was the first to observe radio radiation coming from sunspots and the solar corona.
She was born and raised in Australia. From a young age, she knew how to tune a radio to hear even the weakest signal. After graduating from high school in 1926, she won two scholarships to study at the University of Sydney, where she studied physics, chemistry, mathematics, and botany. After graduation, she continued to work in science. At first, she studied the effect of the Earth’s magnetic field on living organisms and the connection between radiation and cancer. Then she worked for a while at an electronics company, cataloging and calibrating equipment for radio engineers. After that, she joined the Australian Government’s Scientific and Industrial Research Organization.
During World War II, Ruby was engaged in covert work to research radar technology that could track the approach of Japanese fighters.
She was always in the crosshairs of counterintelligence as a member of the Communist Party and a feminist. Her colleagues called her Red Ruby.
After the war, the Radiophysics Laboratory shifted from developing radar systems to using them for scientific research. Payne-Scott’s background as a physicist proved useful and set her apart from her fellow engineers who had no formal training in the field. In October 1945, Payne-Scott and her colleagues established a connection between the flow of radio radiation and the activity of sunspot formation. They published their findings in February 1946 in the journal Nature. In December 1945, Ruby Payne-Scott prepared a report summarizing her observations in the laboratory and suggesting future research directions.
In February 1946, Payne-Scott and her colleagues performed the first experiment using radio interferometry for astronomical observations. The results of their work confirmed that intense radio radiation originated from sunspots and that there was also solar corona radiation in the meter range. Ruby’s research focused on solar wind noise and its relationship to sunspot activity.
In the postwar years, the scientist focused on the study of radio emissions from the Sun and discovered various types of flares. As part of this research, Ruby designed and built an interferometer that could map the radiation power and polarization of the Sun every second, and record the solar coronal mass ejections on a video camera.
In 1944, Ruby secretly got married, because at that time, Australian law prohibited married women from holding a permanent position in the civil service. Eventually, the deception was discovered and Ruby was transferred out of the state despite her protests. In 1951, before the birth of her child, she resigned.
In August 1952, Ruby returned to radio astronomy for a short time, taking part in the 10th General Meeting of the International Union of Radiology at the University of Sydney. After that, she never returned to science again.
Nancy Grace Roman
Nancy Grace Roman: one of the first female leaders of NASA. She was called the “mother of Hubble” for her major role in the development of this space telescope.
Photo: Wikipedia
Nancy has been fascinated by astronomy since childhood. When she turned eleven, she even started an astronomy club among her classmates. They met once a week and read books about the universe. In high school, Roman knew that she wanted to become a scientist and study astronomy.
In the 1950s, having already become a doctoral candidate and having made one discovery, finding changes in the emission spectrum of the AG Draconis star, she was forced to leave the University of Chicago when she realized that she would not be able to build a career in science because of her gender. It was very difficult for women at that time to get a job in research positions at the university. So Nancy went to work at the Naval Research Laboratory. Here, she was surrounded not only by scientists but also by engineers, with whom she learned to get along. Later, this skill came in handy when she became the head of a NASA department.
Once, at a public lecture by a famous physicist, Nancy was approached by a person from the newly created NASA and asked if she knew anyone who could lead the agency’s space astronomy program. Nancy decided that she should apply for the position herself, and in 1959 she was approved for the position. Nancy Roman became the first chief of the astronomy division at NASA and the first woman to be appointed to a senior position in the space agency. As part of her work, she traveled the country, speaking at astronomy departments, finding out what other astronomers wanted, and talking about the benefits of observations from space.
During her time at NASA, Roman developed budgets for various space programs and organized scientists to participate in them. She participated in the launch of three orbiting solar observatories and three small astronomical satellites. These satellites used ultraviolet and X-ray technologies to observe the Sun and other space objects. Its launches also include four geodetic satellites.
Nancy Roman has led projects to launch telescopes into orbit that made observations in the ultraviolet spectrum. Building a space observatory that would observe astronomical objects in the visible wavelength range was more difficult. She spent a lot of energy trying to find funding for this project because it was too expensive. A senator once asked her why American taxpayers should pay for such an expensive telescope. Nancy explained that the amount of money needed was as if all Americans went to the movies once. In return, they would get 15 years of fascinating discoveries.
The Hubble Space Telescope took 12 years to design and build and was launched into orbit when Nancy had already retired. It has made breakthrough discoveries in astronomy and has become one of the most famous devices launched into orbit. Over the years of its operation in Earth orbit, Hubble has captured 700 thousand images of 22 thousand celestial objects: stars, nebulae, galaxies, and planets.
The data stream that it generates daily in the course of observations is about 15 GB. The total amount of data accumulated over the entire period of the telescope’s operation exceeds 20 terabytes. The whole world admired the images of various space objects obtained with the help of Hubble. About 4000 astronomers have been able to use it for observations, and more than 4000 articles have been published in scientific journals.
NASA is currently preparing to launch a new infrared space telescope. It will enter orbit in 2027 and will be named after Nancy Grace Roman.
In space research, both the detail of the images and their scale are important. Telescopes such as Hubble or James Webb have extraordinary sensitivity, which allows them to examine very distant objects in detail. Roman will allow us to look at a large-scale panoramic “canvas”, it will be designed with a much larger field of view.
The image shows how Roman and Hubble’s capabilities will differ in terms of the scale of imaging. The telescope will be used to solve problems such as counting the number of exoplanets in a single galaxy, observing the distribution of galaxies to study dark matter. One of the advantages of Roman will be that, in addition to a large field of view, it will be able to take images very quickly, 1000 times faster than Hubble. According to the Goddard Center, Roman will take about 100 thousand images per year.
Vera Rubin
Vera Rubin: confirmed the existence of dark matter. By studying the rotation curves of galaxies, she discovered discrepancies between the predicted circular motion of galaxies and the observed motion. This fact became one of the main evidence in favor of the existence of dark matter.
We can look at amazing images of cosmic objects taken with various telescopes, but we cannot see most of the Universe. And it’s not because of the long distances, but because all visible matter makes up only about 5% of the Universe, 68% of the entire visible Universe is dark energy, and another 27% is dark matter. Astronomers guessed about its existence in the 1930s, but observations made in the 1970s by Vera Rubin helped prove the existence of this strange substance.
The hypothesis of the existence of dark matter was proposed in 1933 by the American astrophysicist Fritz Zwicky. This is how he christened a substance of unknown nature, which is hidden from optical observations in deep space and reveals its existence solely by its gravity, which affects the structure of galaxies.
Zwicky was not original in coining a new term in astronomy. The Swedish astronomer Knut Emil Lundmark first used the phrase “dark matter” in the same sense in 1930, and a year later his colleague from the Netherlands, the classic of galactic astronomy Jan Hendrik Oort, used it. However, no one paid attention to this term at the time, and Zwicky’s work did not arouse much interest.
Until the 70s of the last century, the existence of non-luminous matter in the Universe was just a good guess. But times were changing, the array of astronomical data was growing, and the purely theoretical assumption began to be confirmed. Vera Rubin was the first to investigate this. She noticed that the orbital velocities of some star clusters contradicted the laws of physics and concluded that they were influenced by some invisible but powerful sources of gravity.
In 1965, Rubin began working at the Carnegie Institution’s Department of Earth Magnetism, where a young researcher, Kent Ford, had recently made a high-precision spectrograph that allowed him to study distant objects much fainter than instruments of the time could. Rubin and Ford decided to investigate the speeds at which stars move in galaxies at different distances from the center, and chose the Andromeda Nebula, the spiral galaxy closest to the Milky Way, for their observations.
Based on the Newtonian theory of gravity, scientists assumed that in such galaxies, the stars farther from the center should move more slowly. But, to their surprise, astronomers were convinced that this is not the case: distant stars move as fast as those located closer to the center.
By the end of the 1970s, Rubin and her colleagues had already studied dozens of similar galaxies and came to the same conclusions. This meant that the stars in the galaxies were held together by something other than the visible matter that could be observed through a telescope. The analysis of the motion of the luminaries showed that most spiral galaxies are immersed in a spheroidal halo of dark matter, which does not show itself in the optical range, but is 5-10 times more massive than the visible matter of the galaxies and extends much wider than the visible part of the galaxy.
In those years, the scientific world was cautious about Rubin’s findings because they contradicted Newton’s laws. However, later, confirmed by multiple observations, her discovery was widely recognized in the scientific world.
Throughout her academic career, she repeatedly faced hostility from male colleagues. However, she was very lucky with her math teacher, whom she recalled as the best mentor of her school years. But her relationship with her physics teacher did not work out so well that in a farewell conversation, he openly stated that he would not recommend her to study science in any case.
Later, she was denied a course in astronomy at Princeton and was also denied observations at the Hale Telescope, where women were not allowed until the mid-1960s. Despite this, Rubin remained focused on her work and maintained a positive attitude. Although it was not fun to face prejudice and stereotypes. When Vera began her academic career in the 1950s, she regularly heard inappropriate remarks about her. For example, during one of her interviews, she was offered the opportunity to leave scientific research and start painting space objects.
Vera did not give up. She not only fought prejudice, but also helped her female colleagues. “In science, there is no task that a man can solve that a woman cannot”, she said. She added: “Women own half the brains in the world”.
For her work, Vera Rubin has been repeatedly honored with various awards: she became the second woman in history to receive the Royal Astronomical Society’s Gold Medal, and she was a member of the US National Academy of Sciences and awarded the National Medal of Science in 1993.
For many years, Vera Rubin was called a possible contender for the Nobel Prize in Physics, but this never happened.
Susan Jocelyn Bell
Susan Jocelyn Bell: discoverer of pulsars.
Pulsars are neutron stars that rotate on their axis and send radio wave beams into space. Their signals can be used as a time standard and reference points for satellites, and subtle deviations in the pulsation can be used to study gravitational waves. In 1974, astronomer Anthony Hewish received the Nobel Prize for the discovery of pulsars. However, the first to notice them was a graduate student, Susan Jocelyn Bell Burnell.
In 1967, he and Anthony Hewish explored the sky with a radio telescope in search of quasars, quasi-stellar radio objects discovered a decade earlier. He developed a radio telescope for such objects, which was built by his students with their own hands, and Bell was also directly involved in this. Under Hewish’s supervision, Bell collected material for her dissertation, operated the radio telescope and reviewed its recordings. Every day, Bell looked through the graphs printed on paper, which vaguely resembled a cardiogram, and searched for signs of sources of strong radio radiation. Bell learned to distinguish noise from the right signals. But then one day she came across strange things in the recordings that she initially thought were a mistake. They looked neither like a signal from a compact source nor like noise, and they belonged to the same area of the sky. Bell assumed that these were signals from a point source, a star, but the interval between the pulses was too short for variable stars – only a second and a third. Hewish believed that these signals were related to human activity. However, Bell continued to study them and was able to convince him to conduct a more detailed study, as a result of which the hypothesis of their terrestrial origin was discarded. The possibility that these were beacon signals from an extraterrestrial civilization was not rejected. The source of the signal was even designated “LGM-1”, from the English Little green men.
The signals appeared again and again, so Bell eventually realized that it was not a mistake, but a space object unknown to science that not only emitted radio radiation, but did so at a clear periodicity.
Soon Bell discovered three more signals of approximately the same periodicity coming from three completely different parts of the sky, and it became clear that these were signals from members of a new class of astronomical objects. They were called “pulsars” for their periodic pulsations in the radio range.
But it was not Bell who won the Nobel Prize, but her supervisor, Anthony Hewish. At the time, in Britain, women scientists often had to deal with public pressure because married women did not work. It was believed that if she worked, her husband did not earn enough to support the family. Bell got married, had a child, and everyone expected her to leave science. But within a few years, she was back to doing what she loved most – studying neutron stars – and gathered her group of astrophysicists at Oxford University.
Bell has never entered into a debate about who should have won the Nobel Prize for discovering pulsars. In 2018, she received the Breakthrough Prize and donated all of it ($3 million) to an organization that supports young scientists.
Today, Jocelyn Bell is Britain’s most influential astrophysicist, a Fellow of the Royal Society of Edinburgh, the Royal Society of London, and the American Philosophical Society. She has been awarded the Herschel Medal, the Royal and Gold Medal from the Royal Society of London, the Presidential Medal of the Institute of Physics, the Grand Medal of the French Academy of Sciences, and many other honors.
