Thread by @DudeDarkmatter

Interesting perspective. It is now over 30 years since I published my first referred paper “An investigation of the efficiencies of various buffer gases in Na-Xe spin exchange”, which has never been cited, even by me. adsabs.harvard.edu/abs/1987PhLA..…

https://twitter.com/jimalkhalili/status/962376458940440583

It did perhaps contribute in a tiny way to making the world a better place as an incremental part of a larger project that ultimately led to useful medical imaging technology. Not that I appreciated that potential at the time; we were just trying to figure out how things worked.

Alkali and noble gas atoms can form weak van der Waals molecules in vapor. In terms of electron shell structure, the alkali is basically a noble with an unwanted electron. Temporary molecules form in which two elements like Sodium and Xenon share the electron like a hot potato.

Turns out that the wavefunction of the electron has a big overlap with the nucleus of the noble. By optically pumping the Sodium D line, we could spin polarize the electrons. Some of this would be transferred to the nucleus, providing a mechanism to spin polarize lots of nuclei.

Spin polarized nuclei light up an MRI imager. By breathing in a chemically inert noble gas with spin polarized nuclei, it enables an MRI to make a detailed image of the lungs, mostly empty soft tissue that is otherwise impossible to image in such detail.

Hence an obscure physics experiment helped in a small way to lead to a useful technology.

As a grad student assigned to do this work, I had zero appreciation for this possible outcome.

All it did was persuade me that I was less interested in table top experiments than the remote laboratory that is the astronomical observatory. So I switched. I left physics grad school, and went into an astronomy program where I knew I could get lots of telescope time.

This turned out to be a better path for me.

I will cop to entering astronomy with a bad attitude. Coming from a rigorous physics background, I assumed this astronomy stuff was trivial and I’d pick it up like a snap. I was very put out that my new grad school wanted me to do two years of grad course work. #beentheredonethat

It was only after those two years of course work, along with doing some serious astronomical research, that I had the epiphany that astronomy was not a trivial sub-field of physics. There were good reasons, historically, technically, and culturally that they were distinct fields.

I mention this in part because I recognize the same attitude in others. On the one hand, I’m glad that many physicists have recognized that there is interesting science to be done from studying the sky, and some fundamental physics to be gleaned from the workings of the universe.

How could I not be pleased by this? They’ve had the same realization I had. But on the other hand, as subjects like cosmology and dark matter became acceptable fields of study rather than fuzzy topics of dubious merit, it became possible to study them within the echo chamber.

Once enough physicists became interested in these topics, there was no need to confront the baseless assumption that the field that started them was inherently inferior. I frequently encounter physicists who still wallow in the bad attitude that I had started with in grad school.

Not all of them, of course. But it is very common now for physicists who work on dark matter to express dismay and contempt for the notion that astronomers could have anything important to say on the subject. Never mind that 100% of the evidence for dark matter is astronomical.

Not 90% or 99% or 99.9%. 100%. Yet the attitude persists, “thanks for the data, let us with the Big Brains take it from here.” I have lost count of the number of physics talks I’ve heard that have a slide acknowledging astronomical data as motivation, then goes off on... whatever

Whatever ill-motivated dark matter model the speaker fancies. Models that could usually be discard immediately with a dash of basic knowledge. Like the Milky Way having an excess of DM clumps from its merger history. But that would thicken the disk! The what? The. Thick. Disk.

The first slide of these talks always shows (1) flat rotation curves and/or (2) the bullet cluster/(3) the CMB. Usually I’m the only person in the audience who has written referees papers on all of those topics. But we’re sure what it means. It is Known, Khalesi.

My point is that there is a lot to learn about the universe. It is a big place. There is lots about it that seems absent from the knowledge base of physicists who are actively working on the subject. This shortcoming can be traced directly to the bad attitude I had in grad school

A bad attitude that still pervades physics. I don’t know where we pick it up as physics students, or how it rubbed off on me personally. It isn’t formally taught. Yet it remains pervasive to this day.

It is socially ugly and is an active drag on the progress of science.