Shedding light on dark matters
posted 1-9-2009 - 7:33 am

 
I started my day yesterday by reading through my usual selection of news sources, then skipped over to check my e-mail, where I was presented with yet more headlines, and ran across a science story in Time magazine that piqued my interest. I ended up pissed off at the reporter, the Nobel prize committee, and academia in general. And thus, a rant developed, but not without cause.

Let me back up a bit here and give you the name of the article first:

The Milky Way: Bigger, Faster, Better Understood
http://www.time.com/time/health/article/0,8599,1870049,00.html

The first thing that struck me was the rather middling handling the reporter gave the story; nothing grossly wrong, just not much in the way of putting this item in perspective so that I know why it's important for me to know any of this. Besides, I've read far better science reporting than this mediocre little bit. The second thing that struck me was that Mark Reid, the Harvard astronomer she interviewed, is really just tweaking the kind of work Vera Rubin has been doing for more than 40 years — and without half as much fanfare and very little public credit.

Who's Vera Rubin, you ask? Ahhhhhhhhhh, here we come to it.

The news story is about more precisely measuring the velocity of our own galaxy as it moves through space. It seems the Milky Way is moving faster than we previously thought. Because velocity is related to mass, this means our galaxy is more massive than previously thought — but because our estimate of the visible matter hasn't changed dramatically, all that additional mass is represented by astronomy's sexiest phenomenon of the moment, dark matter.

Vera Rubin is the gal who discovered dark matter long before we had a name for it. And almost nobody outside of astronomy or astrophysics knows who she is.

Now, when I say that Vera Rubin discovered dark matter, I don't mean she was having an Al Gore moment: I literally mean that she discovered that galaxies weren't behaving as they should if there were nothing in between the visible matter in them. She did this by painstakingly making countless detailed observations and photographs of galaxies. A few others, starting with Fritz Zwicky in the 1930s, had speculated that there might be some 'missing' matter holding galaxies together, but at the time, there were other plausible explanations and nobody had followed up by actually trying to document how galaxies move and making measurements. Until Vera Rubin did. Mind you, she documented the existence of dark matter, but even now we still don't know what it consists of, let alone how it came into existence. There's a lot of speculation, many competing theories, but none that provide sufficient explanation for what Rubin, her colleagues, and her students have documented over the last 40 years. All we know is that 90 percent or more of the universe is made up of stuff that isn't like the stuff that makes up you or me. We're the exceptions; dark matter, whatever it is, is the rule.

Given what a controversial subject and counter-intuitive phenomenon dark matter is, you'd think we'd have heard about Vera Rubin by now. We know Bill Nye the Science Guy; Neil DeGrasse Tyson from Nova and the Hayden Planetarium; Brian Greene, who writes popular books about string theory; and of course, Stephen Hawking — but not Vera Rubin. Her ego's not that big; she's not into self-promotion, nor does she spend a lot of time popularizing science for non-scientists, like the late Carl Sagan did. Rubin just focuses on making astronomical observations, publishing occasional papers, and teaching others how to do what she does. But the science establishment hasn't exactly bent over backwards to tell us about her, either; in fact, like many other women in science, Rubin was actively discouraged by many of her male teachers from entering science and entering astronomy in particular.

Here's what I wonder: how did Time manage to report this story about what Mark Reid and his team are doing without 1) mentioning higher up that the existence of dark matter is still based on indirect measurements like gravitational effects or 2) mentioning that the first proof we had about the existence of dark matter came from photographs of galaxies taken by Vera Rubin, who was ignored and criticized for decades because nobody wanted to deal with the implications of dark matter just then — and because she was a young post-doc and a woman?

Rubin's work showed that galaxies rotate as a unit, kind of like CDs or vinyl records on a turntable, rather than as long 'strips' of stars and dust clouds that would move at differing rates — thus demonstrating that there was unknown 'missing' mass holding together the disc of a galaxy. Long before anyone other than Zwicky was even idly speculating about this particular missing mass in the universe, Rubin was busy documenting the reality that dark matter and Big Bang theorists now have to account for in their theories. In fact, Rubin's work really forced astronomers and astrophysicists to face the question of what constitutes the 'missing' mass in galaxy discs and in the universe as a whole, which prompted the whole business of looking for and identifying dark matter.

To quote the University of Wichita's web page on Vera Rubin's Dark Universe:

" ... Rubin realized that the dark matter she and her colleagues had observed could be the missing mass Zwicky had predicted. Since 1978, Rubin and a team of Carnegie postdocs have analyzed more than 200 galaxies. They estimate that 90% or more of the universe is made of this mysterious dark matter. In other words, everything astronomers had studied until the discovery of dark matter was only one tenth of the universe." But Rubin had actually begun doing that kind of observing while working on her master's thesis; one teacher actually tried to discourage her from publishing her results, warning her that she'd doom her career before it had really begun (she ignored his advice, fortunately).

This is the woman who discovered that most of the universe has this huge, unseen structure to it and is made up of something other than the kind of visible matter that forms human beings, planets and stars. This is also the person that Princeton University profs wouldn't even send a graduate school catalog to because they didn't think women could hack it in science. Yeah, right. Didn't matter, as it turns out: she went to Cornell instead, where she learned from the likes of Hans Bethe and Richard Feynman, then on to Georgetown, where she gained a Ph.D. under George Gamow. She accepted a position at the Carnegie Institution in the 1970s for less than she was making at Georgetown, just so that she could continue her work without the pressure of having to publish often. Seems to have worked out; it's at Carnegie that her work really took off, the place where she's made most of those painstaking observations that others now take for granted when discussing dark matter.

Why isn't her name a household word by now? She's a pioneer of modern cosmology, for heaven's sake: she discovered that the universe is fundamentally A LOT different than we thought it was. How much bigger a deal can you get than that? Had a guy discovered that, by now we would have named at least one mountain, a couple of expressways, several cocktails, maybe an asteroid or a moon, and possibly a new car after him. Vera Rubin gets nothing. Huh??

As it happens, Dr. Rubin finally has a significant degree of respect within her own profession, though it was long in coming; but I'm wondering if she's ever going to get full credit while she's still alive ... and, if she'd been a guy, whether we wouldn't have been talking about a Nobel Prize by now instead of taking her work for granted and giving all the credit to dark matter theorists instead. Mark my words, the folks who will do the heavy lifting on providing evidence for what dark matter is will be, as usual, observational astronomers like Vera Rubin and observational physicists like those at Fermilab or CERN, not the theoretical physicists and theoretical astrophysicists — but whichever theorist has the explanation that most closely matches all those detailed observations will end up with all the credit in public.

Unless, of course, science reporters get smarter and more knowledgeable about the subject matter they cover, so that scientists can be less concerned about publicizing their work and more concerned about actually doing it (but I'm not holding my breath about that; there are a lot of big egos in science).

Vera Rubin discovered something that radically changes how we look at our universe, but she'll probably die without the Nobel committee ever recognizing her work. She is, after all, well past normal retirement age, even though she continues to work anyway (born in 1928; you do the math). Besides, astronomers continue to be underrepresented on the Nobel committee.

Think I'm overstating the case? Hardly: this year's Nobel winners in physics were three Japanese guys (one of whom is at U. Chicago) who received the prize for their work in partially explaining symmetry breaking in particle physics, something that's important to understanding the Standard Model of the universe per the Big Bang theory. Symmetry breaking helps explain why there's more matter than antimatter in the universe, which is how the universe is here at all. However, these three guys each worked on a very small part of this larger discussion; and while what they've done is important in the larger scheme of particle physics and cosmology, their work is still a comparatively more minor part of that discussion than, say, discovering and documenting in detail over the last 40 years that the structure of the universe is radically different than anyone thought.

So why does the Nobel prize committee, among others, continue to ignore Vera Rubin? Well, first, the odds are stacked against women. No, really. Academia is still far more blatantly sexist than a lot of other areas of society (the American Association of University Women can tell you all about that, but I digress). Only two women have ever won a Nobel prize in physics, and only a handful have won Nobels in other disciplines. The first woman to receive a Nobel in physics was Marie Curie in 1903, who won it together with her husband, Pierre, for their work on radiation; the other, U.S. physicist Maria Goeppert-Mayer, shared the 1963 Nobel in physics with Eugene Wigner and Hans Jensen for her discoveries in describing nuclear shell structure (she developed a theory of the structure of the nucleus of the atom while she was at University of Chicago and Argonne National Labs from 1946-60).

Second, only 11 astronomers and astrophysicists of a total 185 recipients have received the Nobel prize in physics; the prize is tilted very heavily in favor of physicists, and there is no separate Nobel for astronomy. The last astronomers to win a Nobel prize were George Smoot and John Mather in 2006 for their work with the COBE (Cosmic Background Explorer) satellite, starting in November 1989, in documenting variations in the cosmic microwave background — the background temperature of the universe that is the leftover heat signature or 'footprint' of the Big Bang (part of the reason their results were as publicized as they were is that Smoot broke with tradition and gave their results to the press before those results had actually been published; academia was furious about that for a while, but even Mather now concedes that the resulting publicity was very useful).

In 2002, two U.S. astrophysicists and one Japanese astrophysicist won the Nobel in physics for their work involving cosmic neutrinos and cosmic x-ray sources. Before that, you have to go all the way back to 1993, when astrophysicist Joseph Taylor shared the prize with partner physicist Russell Hulse for their radioastronomy work in discovering a new type of pulsar. A decade earlier, U.S. astrophysicists Subrahmanyan Chandrasekhar and William Fowler shared the 1983 prize for their work on the theoretical structure and evolution of stars.

In 1978, astronomer Robert W. Wilson shared the physics prize with physicist Arno Penzias for having accidentally discovered the cosmic background radiation (which Smoot and Mather later measured in detail) while Wilson and Penzias were both working at Bell Labs on developing a microwave receiver for radioastronomy. And before that, British astronomers Martin Ryle and Antony Hewish shared the prize in 1974 for their work in developing radioastronomy systems; the committee also simultaneously cited Hewish for the role his work played in the discovery of radio pulsars — even though the person who actually discovered those pulsars, Hewish's then postgrad student, Jocelyn Bell Burnell, went unrecognized (she was the one who first noticed the stellar radio source later identified as a pulsar). Now known as Dame Jocelyn, thank you very much, Burnell discovered the first radio pulsars using systems that Hewish developed and refined — but Hewish got the Nobel (see? Women have been stiffed in astronomy for years; don't get me started).

Oh, yeah: the place where I first read about Vera Rubin and her contributions was in the history of astronomy book series published about 25 years ago by Time-Life Books. Ha! How's that for delicious irony? Perhaps the folks at Time should have perused the stacks at Time-Life books first, before writing the story ...

Rubin has also been very active in encouraging more girls and women to get into science. You can read more about Vera Rubin and her discoveries at:

Answers.com: http://www.answers.com/Vera Rubin
U. Wichita: http://webs.wichita.edu/lapo/vr.htm
NSF: http://www.nsf.gov/about/history/nsf0050/astronomy/darkmatter.htm
Washington Post: http://www.washingtonpost.com/wp-dyn/articles/A42271-2005Mar16.html
Pittsburgh Post-Gazette: http://www.post-gazette.com/magazine/20000320kids9.asp
Discover: http://discovermagazine.com/2002/jun/breakdialogue
Scientific American Frontiers: http://www.pbs.org/saf/1405/segments/1405-2.htm
Newsweek: http://blog.newsweek.com/blogs/labnotes/archive/2008/10/03/the-nobel-prizes-place-your-bets.aspx
Wikipedia: http://en.wikipedia.org/wiki/Vera_Rubin
Peter Gruber Foundation: http://www.petergruberfoundation.org/Site/cosmologynews_2002.htm
SpaceRef.com: http://www.spaceref.com/news/viewpr.html?pid=11424
UCLA: http://www.physics.ucla.edu/~cwp/articles/rubindm/rubindm.html
BookRags: http://www.bookrags.com/Vera_Rubin

Whew! I feel better now.