Kelly McSweeney

Apr 13th 2020

Vera Rubin Solved the Darkest Mysteries of the Universe


Vera Rubin proved the existence of dark matter, the invisible substance that makes up 27% of the universe. Her work on galaxy rotation rates uncovered discrepancies between theories and observations of the universe. Ever a scientist, she asked questions that led to even more questions, and she researched and analyzed hundreds of galaxies. Rubin did this while also raising four children and facing gender discrimination.

Rubin’s Greatest Discovery

Our understanding of the universe has evolved thanks to contributions from many scientists, including Vera Rubin. Throughout her career, Rubin studied hundreds of galaxies and collected valuable data about what’s going on in space. Her number one claim to fame is all about dark matter.

While Newton’s laws suggested that gravity existed, Albert Einstein later explained how it worked. His 1916 theory of general relativity described how massive objects cause a distortion in the space-time continuum — but it still didn’t explain everything. In the 1930s, astronomer Fritz Wicky noticed that galaxies in clusters moved faster than expected, based on the observable mass. According to Nature, Wicky suggested that galaxies have something else that we couldn’t observe. This mysterious substance doesn’t emit or absorb light and makes up 27% of the universe. Not to be confused with dark energy (a force that pushes things apart), dark matter is a substance that pulls objects toward it. According to Nature, Vera Rubin observed dark-matter halos, which contain most of the mass in the universe.

In the 1970s, she worked with her colleague Kent Ford to measure the speed of stars and show how mass was distributed in spiral galaxies. Ford built an optical instrument called a spectrograph, and together they used it to observe the light from stars in different parts of spiral galaxies.

They expected to see that stars on the outskirts moved slower than those in the center, where most of the galaxy’s light was located. The idea was that light indicates mass, which explains the gravity that keeps the galaxy together. But it didn’t quite add up. Rubin and Ford were surprised to discover that the stars at the dark edge of galaxies were moving just as fast as the stars in the densely-populated centers of galaxies. In 1978, they published a paper on flat rotation curves that confirmed the existence of dark matter. Rubin’s calculations showed that galaxies contain about 10 times as much “dark” mass as visible matter, meaning that nearly 90% of the universe is dark and unknown, according to the American Museum of Natural History (AMNH). Today, dark matter is still one of the biggest mysteries of astronomy, but at least thanks to Rubin, we know it’s there.

Smashing Glass Ceilings

From a young age, Rubin was interested in science, although she wasn’t always encouraged to pursue a career that was dominated by men. According to AMNH, when she applied to graduate schools she was told that Princeton didn’t accept women into the astronomy program. She went to Cornell University for her master’s instead and earned her doctorate from Georgetown University in 1954.

According to the New York Times, Rubin had to push for access to a 200-inch telescope owned by Carnegie and Caltech. When she got into the facility, she found there wasn’t even a women’s restroom. (She quickly solved this by taping a skirt to the image of a man on the bathroom door.) She faced these career barriers while also raising four children, who all eventually grew up and earned their own doctorate degrees.

In a 1989 interview, she told the American Institute of Physics the story of how her male professors at Cornell tried to steal credit for her work.

She said, “The department chairman said that in as much as I was going to have a child and therefore couldn’t go to the meeting to give this talk, he would give it, and in as much as I wasn’t a member of the AAS [American Astronomical Society], a member’s name would have to be on the paper. He really had nothing to do with what I had done.”

Therefore, she decided to go, no matter the barriers. She enlisted her father to drive from Ithaca to Philadelphia through a snowstorm with her nursing, newborn baby in tow. She presented her paper in a 10-minute talk to a room of AAS members.

Recognition for Her Work

Like many of the hidden figures behind scientific breakthroughs, Rubin paved the way for future women in STEM careers. She didn’t always get the recognition she deserved, but Rubin was elected to the National Academy of Sciences and was awarded the National Medal of Science in 1993. Even after her death, she’s still breaking barriers. In 2020, it was announced that the Large Synoptic Survey Telescope (LSST) will be named the Vera C. Rubin Observatory. It’s the first national U.S. observatory to be named after a woman. Now, future astronomers can visit the Rubin center in Chile, an ideal location for astronomy, to study dark matter and other objects in the sky.

In the LSST’s announcement, Rubin’s children released a statement about this overdue honor: “We believe that this is a great way to honor our mother’s achievements in astronomy and her work for equal rights for women in science.”