Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.


Vera Rubin and the dark matter problem

In my view, Neta Bahcall's obituary of Vera Rubin oversimplifies the dark matter problem (Nature 542, 32; 2017). Many diverse observations have contributed to the current picture, and the unknown nature of dark matter shows that this is still far from complete.

Rubin investigated rotational velocities in spiral galaxies using ionized gas regions that she was able to observe at optical wavelengths. In the 1970s, such regions could not be detected beyond a galaxy's optical image. The observed rotation curves therefore did not extend far enough to demonstrate the presence of dark matter convincingly, even though the flatness of their outer parts might convey that impression.

At that time, I and several other astronomers used the 21-centimetre radio wavelength of neutral hydrogen to determine rotation curves that often went well beyond the optical image, thereby probing the dark matter regime more effectively.

Such observations from several galaxies, coupled with optical surface photometry, permitted the calculation of local mass-to-light ratios in the outer parts of spirals (A. Bosma PhD thesis 1978; see This clinched the evidence for dark matter and still constitutes the primary source of rotation-curve data for exploring its mysteries.

Author information



Corresponding author

Correspondence to Albert Bosma.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Bosma, A. Vera Rubin and the dark matter problem. Nature 543, 179 (2017).

Download citation


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing