The role of luck in science is something I sometimes feel we just don’t acknowledge enough. To do amazing things, you don’t just have to be one of the best in the world in terms of intellect and research skills, you also have to sometimes get lucky that the kind of object you’re interested in goes off at the right time and in the right place for you to get the data you need.

On Thanksgiving Eve in 2018, the Swift observatory caught a short gamma-ray burst (GRB) – the kind of high energy flash that occurs when two neutron stars merge. Only a handful of these occur each year, and each is thought to be accompanied by a flash of optical light that lasts for tens of minutes to a few hours. Seeing these flashes is necessary to confirm the gamma-ray burst’s location in the universe, but these often distant phenomena are super hard to observe. 

To catch these events, the bursts, first of all, need to appear in the sky over the part of the planet that is dark, and then a telescope needs to be found that can go looking for whatever may or may not be visible. Telescope time is pre-allocated to different researchers who are generally doing something other than looking for gamma-ray burst afterglows. As someone who’s gotten the pre-dawn call to “please go chase a GRB”, I can tell you that the process generally involves a fair amount of cursing, stumbling out to the dome to point the telescope at something in a radically different part of the sky, watching the telescope slowly slew, stumbling back into the control room, and then taking images based on a wild guess of what exposure times should be used. 

My personal attempt to do follow-up for some researchers didn’t uncover anything, but Northwestern University’s Wen-fai Fong had a very different experience. Making the call to Gemini Observatory that Thanksgiving Eve, his team was able to get one of the best telescopes in the world to slew to the right place in the sky where they pinpointed the light of a short gamma-ray burst that went off order of ten billion years ago. Named SGRB 181123B, it is now the most distant short gamma-ray burst ever observed, and this identification seems to indicate that neutron stars can merge relatively quickly in the young universe. 

Let’s put this in context: our universe formed 13 something billion years ago. The cosmic microwave background (CMB) was released 400,000 or so years after the universe formed. A few 100 million years later, stars were forming and galaxies were starting to take shape. Some of the largest stars forming in these early times evolved into neutron stars in a binary system, and those stars rapidly spiraled together to merge before the universe was even four billion years old. That light then traveled in all the colors of the electromagnetic spectrum to Earth, where the gamma-rays triggered a space telescope that detected the light at a time of day that made observing with the 8.1-meter Gemini telescope in Hawaii possible. Also, Fong had done all the things, made the necessary proposals, and been awarded all the needed privileges to have permission to take over usage of that particular telescope from whatever else it was doing on that particular night.

That, folks, is luck combined with all the necessary preparation. 

And this is how we advance our understanding of the universe, one hard-won lucky break at a time. This work appears in a new paper in the Astrophysical Journal Letters.

More Information

Northwestern University press release 

“Discovery of the Optical Afterglow of Short GRB 181123B at z = 1.754: Implications for Delay Time Distributions,” Kerry Paterson, Wen-fai Fong et al., 2020 July 14, Astrophysical Journal Letters (Preprint on arxiv.org)