Katie Mack has been training as a cosmologist since about the age of 10 when she decided she wanted Stephen Hawking’s job. She got her bachelor’s in physics at Caltech, PhD in astrophysics at Princeton, did an STFC postdoctoral fellowship at Cambridge, and is now a DECRA postdoctoral researcher in theoretical astrophysics at the University of Melbourne.

Her work focuses on finding new ways to learn about the early universe and fundamental physics using astronomical observations, probing the very building blocks of nature by examining the cosmos on the largest scales. Throughout her career, she has been working on the interface between astronomy and particle physics, studying dark matter, black holes, cosmic strings, and the formation of the first galaxies in the Universe.

Katie is also an active science communicator, participating in a range of science outreach programs such as Scientists in Schools and Telescopes in Schools. Her popular writing has appeared in Sky & Telescope, Time.com, and the Economist’s “Babbbage” tech blog, among others. She occasionally co-hosts a YouTube astronomy chat series called “Pint in the Sky.”

Katie blogs at The Universe, in Theory and tweets as @AstroKatie. Her ORCID is 0000-0001-8927-1795.

A couple of years ago, I was gathering my things after a seminar at a top physics research institution when I overheard two of the senior professors discussing a candidate for a senior lectureship.

Professor A was asking Professor B if the candidate had a partner, which might make him less able to move internationally.

Prof B replied, happily: “No, he has no family. He’s perfect!”

I doubt any selection committee would admit on-record to thinking a family-free candidate is “perfect”. Nonetheless, the traditional academic career structure is built around an assumption of mobility that is hard to maintain with any kind of relationships or dependents. I’m still trying to figure out if I can manage to keep a pet.

Right now I live in Australia, working as a postdoc in Melbourne. My first postdoc was in England. Before that I was in grad school in New Jersey, and I was an undergrad in my native California. Halfway through grad school I studied for a year in England. I’ve done two- or three-month stints in Japan, Germany, Australia and the UK. Each of these moves or visits has been, while not strictly required, extremely helpful for my career. And in a field where competition for jobs is so fierce, if you want any hope of landing that coveted permanent academic job, how many of these “helpful” moves can you really consider optional? If mobility is such an advantage, how does having a family or a partner affect your chances?

A couple of months ago, Slate published an article with the headline, “Rule Number One for Female Academics: Don’t Have a Baby.” The point of the article wasn’t actually to discourage women in academia from having children (though backlash from the community may have contributed to the change in title to the somewhat vague, “In the Ivory Tower, Men Only”). The article provided statistics and anecdotes to illustrate how having children, or being suspected of the intent to have children, could harm a woman’s progress in academia – from the necessary pause in research output, to the unconscious or explicit biases that act against “working mothers” but have no similar effect on “working fathers”. Personally, I found the piece deeply disheartening, but my dismay was of a somewhat detached variety. In order to worry about the effects of having children, one has to be in a position where that seems like even a remote possibility. As a single woman with a short-term contract and no idea which hemisphere I’ll be in two years from now, children are not exactly at the forefront of my mind. At the moment, I spend a lot more time thinking about the two-body problem.

In this context, the “two-body problem” is the problem of maintaining a committed relationship between two individuals who are trying to have careers in academia. When the two-body problem proves unsolvable, it’s sometimes called “academic scattering”. It is by no means unique to academia, but the international nature of the field, the frequency of short-term (1-3 year) contracts, and the low wages compared to other similarly intense career paths make it especially bad for academics. In the sciences, the gender disparity adds a further complication for female academics: when women make up a small percentage of the discipline, they are much more likely to be partnered with other academics.

Of course, solving the two-body problem is not impossible. I have many colleagues who have done it, either through spousal hires, fortuitous job opportunities, extended long-distance relationships, or various degrees of compromise. It takes sacrifice, luck, and, often, institutional support. But couples just beginning a relationship while building two academic careers might find the odds stacked against them. Even ignoring for a moment the fact that a no-compromise work-obsessed lifestyle is still considered a virtue in many institutions, academic careers are structurally best suited to people with no relationships or dependents, who travel light and have their passports at the ready.

It varies by field, but for physics and astronomy, a “typical” tenure-track career path looks something like this: 4-6 years in grad school, a postdoctoral fellowship for 1-3 years, then usually another (and maybe another), all followed by a tenure-track or permanent job, which may or may not be the job you end up in for the long-term. There’s no guarantee all these steps will be in the same country – very often they are not. For me, it’s been an international move every time so far, and it’s very possible the next one will be, too. When I took up my first postdoc, I left my country of origin, most of my worldly possessions, all my friends and family, and a committed relationship, to start all over in England. When I took up my second postdoc, I left my newly built life in England and another committed relationship to start all over yet again on the other side of the world. I’ve moved internationally several times chasing the prospect of permanent academic employment. I have yet to convince anyone to come with me.

I’m not trying to convince anyone that avoiding academia or refusing to move around the world is the key to solving all relationship problems. Anyone can be unlucky in love, even if they stay in the same city their entire lives. But academic shuffling is particularly hostile to romance. The short-term contracts mean that when you arrive in a new country, if you’re interested in finding a long-term partner, you have something like two years to identify and convince a person you’ve just met to agree to follow you wherever you might end up in the world, and you won’t be able to tell them where that will be. If you happen to have different citizenships (which is likely), you have to take into account immigration issues as well – your partner may not be able to follow you without a spousal visa, which can mean a rather hasty life-long commitment, or, depending on the marriage laws of the country in question, a total impossibility. I had a friend in grad school who, at the end of her PhD, faced a choice between living with her wife in Canada, and becoming a tenure-track professor at one of the most prestigious research universities in the USA.

The timing doesn’t help, either. The postdoc stage, when you’re doing your best impersonation of a human pinball, usually comes about in your late 20s or early 30s. It’s a time when it seems like all your non-academic friends are buying houses, getting married, having babies, and generally living what looks like a regular grown-up life. Meanwhile, chances are you’re residing in a single room in a short-term rental, wondering which country you’ll be living in next year. If you’re a woman, you might be keeping an eye on the latest research on fertility in older mothers, and mentally calculating how long you actually need to know someone before deciding to reproduce with them, because by the time you’re in one place long enough to think about settling down you’ll be, at best, pushing 40.

There are lots of ways to make it all work out, of course. You could refuse to date other academics, and instead make sure you’re spending enough time on hobbies outside of the university to attract someone’s interest, while making sure you have a REALLY good pitch about the joy of imminent mystery relocation. You could date another academic, and resign yourself to a relationship that will probably be long-distance for far longer than it was ever face-to-face, with no guaranteed reunion in sight. For this option, make sure that you have lots of disposable income for plane tickets and that neither of you is committed to spending too much time inside a lab. You could swear off serious dating altogether until you’re getting close to landing a permanent job, then negotiate with your future employer for a spousal hire, with the necessary career compromise that will be required of one or both of you to be at that particular institution. Or you could just wait till you’ve scored a permanent faculty job somewhere, probably in your mid-to-late 30s, and (if you’re a woman) hope that you meet someone soon enough that starting a family is still an option. (As a side note, my late-thirties single straight female friends tell me that men who want babies won’t date women over 35. Obviously this is an unfair and unscientific generalization, but the point is that there are societal pressures that women face when they choose to put off the prospect of families until they have permanent jobs.) If you choose this option, you might also want to keep in mind that a tenure-track job isn’t necessarily permanent, and having a child before having tenure is one of those options that the aforementioned article had a few things to say about.

Or you could decide to prioritize where you want to be (or who you want to be with), and, more likely than not, end up severely limiting your career progress and/or leaving academia altogether. If one or the other partner does have to make a big career sacrifice, gender norms will suggest that, if you’re a woman, the one to make the sacrifice really ought to be you.

As for me, I confess I haven’t figured it out. I have two years left on my contract in Australia and no idea whatsoever which country I’ll end up in next. I’m applying broadly, and there’s no guarantee I’ll have a choice about location if I want to stay on the path toward becoming tenure-track faculty at a major research institution. When it’s not unusual for a single postdoc job to have 300 applicants, and faculty jobs are even more selective, getting even one offer is considered a huge win.

I don’t know if there’s a solution. Having a pool of early-career researchers who move frequently to different institutions unquestionably advances research and keeps the ideas flowing. It is also usually great for the development of postdocs’ research abilities, exposing them to new ideas and work styles. But the prospect of a nearly decade-long period of lifestyle limbo between graduate studies and the start of the tenure track is, understandably, a significant discouragement to many fine researchers who might otherwise bring their unique insights to the field. And, statistically, more of these lost researchers are likely to be women. It may not be the dominant force keeping women out of science or academia, and it may not affect all women, but any slight statistical skew that disadvantages women more than men contributes to the inequality we see. And that makes academia a little bit more lonely for everyone.