Vera Rubin (The Astronomer & An Observatory)

FAS Astronomers Blog, Volume 33, Number 6

Vera C. Rubin

Vera Rubin worked as an astronomer at Georgetown University and the Carnegie Institution of Washington. She came a long way despite being a woman back in the days when astronomy was dominated by men. She couldn’t attend graduate school at Princeton because women were not allowed into the program she was interested in. She eventually went to Cornell and Georgetown University. Even then, she had to deal with an advisor offering to present her work at an American Astronomical Society meeting – under his name – not her’s. She was one of the first woman to do research at the Palomar Observatory. Upon arriving there, she discovered that Palomar didn’t have a woman’s restroom. Her solution was simply to draw a skirt on the symbol for the men’s room. 

Vera Rubin remained a supporter of women in science all her life. According to Neta Bahcall, she pointed out that “Worldwide, half of all brains are in women”.

In the 1970s, Dr. Rubin along with Kent Ford studied the way in which galaxies rotate. She expected to find that stars in the outer arms of a galaxy orbit the galactic center slower than those in the inner part of the galaxy. This is based on Kepler’s 2^nd law of motion which says that planets close to the Sun orbit faster than those far from the Sun. We see this in our Solar System; Neptune moves at a much slower rate than Mercury. Kepler’s law actually talks about planets sweeping out equal areas, but this means the same thing. Kepler’s laws were later found to be the result of Newton’s laws of gravitation. 

Rubin and Ford were surprised by their results. Stars rotated at the same rate regardless of their distance from the galactic center. This was a direct contraction to Kepler’s law and Newton’s laws of gravity. 

This finding led to the conclusion that galaxies contain much more matter than we can see, and that most of the mass in the Universe is made up of what is call “dark matter”. Initial indications of dark matter came from the work of Fitz Zwicky and Jan Oort before him. Their work didn’t receive much attention. It was Rubin and Ford that brought dark matter into the light (no pun intended). A few years later James Peebles and others put dark matter on a firm theoretical ground with the Cold Dark Matter (CDM) model of the Universe.

Peebles received the 2019 Nobel Prize for his work. Regrettably, Vera Rubin passed away in late 2016. Many think she deserved a Nobel Prize, but the Nobel is not given posthumously and for her it is too late. 

Vera C. Rubin Observatory

However, her story is not done. The Vera C. Rubin Observatory is a new observatory located in the Andes mountains in western Chile. Although, it is not one of the new 30-meter telescope currently being built, the Rubin Observatory may be a significant step forward in our understanding of the universe. 

At 1.86 miles (2,700 meters) above sea level on Cerro Pachón in the Andes mountains, the Rubin Observatory has an unobstructed view of the entire southern sky. Its LSST camera, with 3.2-gigapixels, is the size of a small car and weighs over three tons. According to the Conversation, it could spot a golf ball 25 km away. Unlike the James Webb Space Telescope (JWST), the Rubin Observatory is designed to take large scale images of the sky. A such, it will look for evidence of dark matter, dark energy, near Earth asteroids, and maybe even Planet Nine. 

On June 23, 2025, the Rubin Observatory will release its first set of images. You can join in on YouTube beginning at 11:00 am EDT. Update: The images have been released – see them here.