Vera Rubin, the astronomer who discovered dark matter, died on Sunday. The New Jersey resident's son, Allan, told the Associated Press that her death was due to natural causes. Rubin had stargazed since she was a kid and studied astronomy at Vassar and Cornell, according to the American Museum of Natural History. She went on to teach at Georgetown and conduct research at the Carnegie Institution, where she did her famous work on spiral galaxies that led to her theory of dark matter. Dark matter is the invisible stuff that makes up 27% of the universe's mass and energy and 84% of its material. It's become the subject of many a sci-fi movie and even the name of a show, as well as the grounds for popular scientific theories and experiments. The science community pushed for Rubin to get a Nobel Prize, hoping she'd break a more than 50-year streak without a female winner, according to The Washington Post. One supporter of this movement, University of Washington astronomer Emily Levesque, told Astronomy.com that "the existence of dark matter has utterly revolutionized our concept of the universe and our entire field; the ongoing effort to understand the role of dark matter has basically spawned entire subfields within astrophysics and particle physics at this point." Rubin never got a Nobel Prize, but she was the second woman astronomer to join the National Academy of Sciences. "I really feel very much that I'm an observer, and I tend to relate what we know about the universe to what has been observed," she said in an interview published by the American Institute of Physics. "We're still groping for the truth. So I don't really worry too much about details that don't fit in, because I put them in the domain of things we still have to learn about. I really see no reason why we — and include all of us in this generation — should just have been lucky enough to live at the point where the universe was understood in its totality. [...] Science consists of just continually making better and better what has been usable in the past."