Vera Rubin and Observing Galaxies

Vera Rubin (1928-2016) An extraordinary woman who left a powerful scientific legacy, as well as a powerful personal legacy of what it means to be a scientist.

26 Dec 2016

I love observing galaxies, and I can never look at them without thinking of the remarkable astronomer Vera Rubin. I think of her not for what I am seeing in my eyepiece, but for what I am not seeing: dark matter, evidence for which she discovered.

As she famously said, “Most of the matter in the Universe is not radiating at any wavelength that we can observe… And that is a rather daunting idea. We became astronomers thinking we were studying the Universe, and now we learn that we are just studying the 5 or 10 percent that is luminous.”

It’s now believed that more than 90 percent of the universe is composed of dark energy and dark matter – but dark matter is extremely mysterious and elusive; it does not reflect, absorb or emit light, making it invisible. Because of this, it is only known to exist via its gravitational effects on the visible universe. (The best description of dark matter comes from the astrophysicist Adam Frank, who described it by comparing it to a ghost in a horror movie. “You can’t see it, but you know it’s with you because it messes with the things you can see.”)

It is hard to overstate the importance of Dr Rubin’s discovery; it was truly monumental because it revolutionised astronomy and changed the way we think about the universe. Dark matter is foundational to our understanding of how the universe evolves and how galaxies form. It’s at the heart of what the universe is made of and why we are here in our galaxy today.

The existence of dark matter had been proposed by Swiss astrophysicist Fritz Zwicky in the 1930s, but hadn’t been confirmed until Dr Rubin’s work. As science writer Carolyn Collins Petersen, wrote, “If it hadn’t been for her, we would not be where we are with what limited understanding of dark matter we have now. We know that it’s ubiquitous about the cosmos, but it’s also figuring out the distribution and why it’s clumping around galaxies. If it wasn’t for her, I don’t think we’d even be able to ask those questions yet.”

And Kirk Borne, who studied colliding galaxies as a postdoctoral researcher with Dr Rubin in the early 1980s, wrote, “The biggest contribution she made was collecting all the evidence that supported the existence of dark matter in galaxies and characterizing it to the best degree possible. She stayed focused on that one problem, and comprehensively solve it for the rest of the world.”

Vera Rubin makes observations through the Flagstaff Telescope. Image credit Smithsonian Institution

A remarkable scientist. A remarkable achievement. And indeed, it is a remarkable experience to look through my eyepiece at some of the vast galaxies that inhabit our universe and, thanks to Vera Rubin, have some small further understanding of how the universe works. I spent hours last night examining the Dorado Group of galaxies, meandering among them, quite overcome with awe at what they are, how they are, and why they are.

And as for their beauty? They may be but small smudges of silky grey light in my eyepiece, but to me their extraordinary shapes and their incredibly bright nuclei are beautiful beyond all measure. Which reminded me of one of Vera Rubin’s most charming reflections, “I sometimes ask myself whether I would be studying galaxies if they were ugly. I really do, and I’m not sure. I see ugly bugs. My garden is full of slugs. I sometimes think, well, maybe if I started studying them, they wouldn’t appear to be so ugly… I put that at the other extreme. I think it may not be irrelevant that galaxies are really very attractive.”

Unbelievably, Dr Rubin was never awarded the Nobel Prize for her ground-breaking work, an honour that would have matched the significance of her discovery. The Nobel Prize in physics is designated for “the most important discovery within the field of physics” – which pretty much describes her titanic universe-changing contribution to the enterprise of science.

Sitting out under the stars last night and thinking about her was a poignant experience because she herself went to the stars yesterday on Christmas Day at the age of 88. But it was also joyous because, sitting in the dark all night and peering into the unfathomable depths of our universe, I realised that the failings of the Nobel committee to recognise her doesn’t matter because Vera Rubin’s name is writ across the universe in invisible ink.

This gorgeous galaxy in Dorado was the showpiece of my galaxy observing last night…

NGC 1566 Galaxy

RA 04 20 00.8 Dec -54 56 14 Mag 9.7 Size 8.3’ x 6.6’ SB 13.9

NGC 1566 is undoubtedly the pièce de résistance of the Dorado group of galaxies is absolutely stunning in my 16″ Dobs at 228x and 333x! A big round glow – very bright – that brightens to a very bright nucleus. A little brighter mottling in the halo and there is the slightest sign of a spiral attached on the north side of the core, and what I can see of it allows me to realise that it wraps around counterclockwise on the east side (although I can’t actually see its wrap-around). A very handsome galaxy! Yes, indeed, “… galaxies are really very attractive.”