Vera Rubin: The woman who unwound Dark Matter’s cosmic spindle

rubin

Among so many celebrity and A-listers deaths this year, the passing of some less well known (but by no means less important) people has all but gone unnoticed.

Vera Rubin was the American astronomer who first proved the existence of Dark Matter. Initially met with skepticism by the scientific community -mainly because she was a woman-, Rubin would come to be vindicated in later years, as her theories and discoveries proved to be correct.

Dark Matter: The Great Universal Enigma

There is a great universe out there. Ever expanding, all entities contained in such gigantic grain of sand keep moving at a steady pace away from each other.

The 14bn-year-old (give or take some loose millions of years) three- (or fourth-, if you listen to some theorists) dimensional Universe grows and grows in apparently
random directions, and all galaxies, nebulae, black holes, and whatever other space stuff is out there moves at dizzying speeds.

And this is only the observable Universe. In other words, the portion of Universe, however vast, that contains the light that has had enough time to reach us since the Big Bang occurred, all those billions of years ago.

But wait. If we can only see some of the Universe, what’s beyond this visible slice of Universal cake?

And more importantly, what holds the Universe together? Dark Matter, that’s the invisible thread that binds all things together out there.

Now, enter Vera Rubin.

‘As long as you stay away from science you should do okay.’

So an ill-advised school physics teacher said to a young Vera Rubin. But fortunately for the science community, she paid little heed to such cheap negativity.

A daughter of Jewish immigrants, Rubin’s interest on astronomy began when she was 10 years old. She had recently moved to Washington DC with her family, and the stars she saw through her bedroom window held the young Rubin in their thrall.

But Rubin’s path to the stars would not be an easy one.

In 1947, at 20 years of age, Rubin requested a graduate-school prospectus from Princeton University, only to be told by a dean that women were not accepted into the program (females would not be allowed to enroll in Princeton as undergraduates until 1969.)

She was also unable to attend Harvard because she married young, and followed her husband to Cornell University in New York, where he was studying physics. The young bride would go on to obtain a master’s in Astronomy at Cornell.

Undeterred by these artificial barriers, Rubin learned most of what she knew by conducting her own research, away from ‘centers of excellence.’ This circumstance would play against her, as fellow scientists would have a hard time accepting anything outside the norm.

Dark Matter: The unseen force that binds the fabric of the Universe

Let’s go back to that big bad Universe for a moment.

The Universe is full of stuff, that much everyone kind of agrees. Understanding this stuff, well, that’s another matter.

Back in the 1960s, the convention was that galactic mass was concentrated around a galaxy’s bright center. Based on this assumption, it would stand to logic that stars located the farthest from the center would move on a slower orbit, as they would be subjected to less intense gravitational pull.

However, Rubin’s research concluded that the speed at which remote stars orbited the galaxy’s center was about the same as stars closer to it.

This, according to Rubin, suggested that there must be another, yet unseen gravitational force, at work.

The existence of Dark Matter had been postulated as far back as 1933. Technological limitations of the era, and the advent of Second World War prevented any serious research into it, however. Rubin’s work infused new life into the pursuit of this elusive cosmic mystery.

Conducting pioneering work with fellow astronomer Kent Ford, Rubin used our closest galactic neighbour, Andromeda, as an example. The team discovered that the rotational speeds of Andromeda’s stars increased rapidly as they moved towards their orbit’s edges, then levelled off. And these rates did not decrease, irrespective of the star’s distance to the central galactic mass. Rather, they became a constant value.

But what was most revealing was that the star’s rotational curve (that is, the orbital speeds of visible stars) remained flat. This contravened all expectations and accepted astronomic conventions of the time.

Admitting that this might have been a phenomenon occurring locally at Andromeda, she looked at other galaxies. Astonishingly, she observed the exact same behavior.

In layman terms, Rubin discovered that most stars present in spiral galaxies orbit at roughly the same velocity, a concept that would defy the established laws of the Universe.

Vera Rubin’s cosmic legacy

Rubin’s groundbreaking work was met with deep skepticism and mistrust, for two reasons: Her unconventional path to learning, and most of all, because she was a
woman.

Galaxies and stars are caught in the thrall of something called dark matter, named so because it remains invisible to the entire electromagnetic spectrum. In other words, we can’t see it, at least current technology can’t.

But thanks to Vera Rubin, we know it’s there, molding and handling entire galaxies into shape.

Rubin died of natural in an assisted-care facility in Princeton, New Jersey, at the age of 88. She had suffered from dementia for a number of years.

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