Exoplanets -- planets that orbit stars other than the sun -- are everywhere. Every star in our galaxy, on average, has at least one planet of some kind. Announcements last week from the largest annual gathering of astronomers included the finding that one in six stars like the sun host an exoplanet close to Earth's size. For our Milky Way Galaxy that has on the order of 100 billion stars, this means an astonishing 17 billion Earth-sized planets. This is the first time any exoplanet finding technique (the transit technique, by NASA's Kepler Space Telescope) has been sensitive enough to reach down to a statistically significant numbers of small planets. The ultimate goal is to find small, rocky planets like Earth that can support life, and although the one in six star findings are for planets with orbits so close to their stars they would be too hot to support life, many other lines of evidence point to the ubiquity of rocky worlds. We are discovering that no matter where we look or how we count, small planets are absolutely everywhere.
The half-dozen or so news-making exoplanet results at the American Astronomical Society's meeting in Long Beach, Calif. were almost all led by male astronomers. The paucity of impact-making announcements by female astronomers in general is dreadful. How can it be, that well over a century after the first women received PhDs in astronomy, women have failed to match their male peers in this and other aspects of STEM academia?
One issue relates to what do we do next in exoplanets. Instead of just statistics, we want to find real examples of Earth-like planets orbiting the nearest stars. To identify planets as Earth-like (instead of just Earth-size) we require a different kind of and much more sophisticated space telescope than Kepler. The telescope must be able to observe planets directly, by blocking out light from the 10 billions of times brighter adjacent host star. With this so-called direct imaging planet finding technique and the right instrumentation, an exoplanet's atmosphere can be observed to determine if the planet is habitable (via evidence for liquid surface water, needed for all life as we know it) or if the planet is possibly inhabited (via atmospheric gases that can be attributed to life).
Recently a call went out from NASA soliciting applications for membership in two Science and Technology Definition Teams (STDTs) for just that next step: exoplanet direct imaging space missions. The purpose is to study two different mission concepts (one with per team) under a cost cap of 1B, which is considered a possibility within the next decade. Although these missions will likely not reach down to Earths, the technology development is on the critical path and larger exoplanets would be accessible. Such committees are important not only for moving the community's goals forward, but the networking for individuals can provide tremendous opportunities for climbing the career ladder and future projects.
I was excited until I read in the STDT charter that face-to-face meetings will be quarterly, and the first meeting is at an extremely inconvenient geographic location. Quarterly means six trips for the duration of the STDT. By far not a small number when combined with all of the other travel imposed on those at or trying to reach the academic forefront. This kind of travel becomes extremely challenging for women who are the primary caretakers of children because of the heavy toll it takes on families. In my opinion, the expectations for travel at all levels of career stage -- illustrated by and not limited to this particular example -- make it far harder for women to climb the academic ladder and can be seen as exclusionary.
I never noticed travel as a women's issue in academia as previously my part-time employed husband held down the homefront while I traveled constantly to meetings, even while pregnant or with an infant in tow. I ignored the stress it placed on my spouse, although I always made sure to do several loads of laundry before leaving and hire a babysitter to provide extra help in the evenings. Not every scientist has such resources, and indeed the issues facing women who are primary caretakers of children became all too clear to me when I recently found myself a widowed single mother of two. Of course there are other reasons beyond travel to committees that women (with and without children) are struggling with in STEM academia and I will explore those in later blogs.
The good news is that after I communicated to the committee organizers that the Exoplanet Direct Imaging Mission Concepts STDT charter appeared discriminatory to me because of the travel requirements, one of the organizers, to his credit, acknowledged that he was unaware travel and geography were problematic and asked for suggestions of how to make the charter more inclusive. Change for a fair playing field for women in academia is still possible, but at how much effort to constantly educate the male vanguard?
Back to exoplanets. Based on the new announcements, it is simply breathtaking to realize that some of our very nearest neighboring stars must have Earth-size planets. Beyond finding and identifying habitable worlds, it is a thrilling journey to begin to map the nearby stars, to aim to find all of the terrestrial planets orbiting stars within 30 light years of Earth. I believe that hundreds to a thousand years from now people will find a way to travel to the planets orbiting the nearest stars and will look back at us as the generation of people who first found the Earth-like worlds. And, hopefully, long before that distant time we will have achieved equality for all humans.