Searching the Stars for Extraterrestrial Life
Casey Brinkman '17 is part of a team that’s unraveling one of astrophysics’ greatest mysteries
- By Joshua E. Brown
It’s been a tough winter for aliens. Earlier this month, astronomers showed that the flickering of the so-called Tabby’s Star—some 1280 light-years away in the constellation Cygnus—was not, in fact, caused by a huge sphere built around it by extraterrestrial beings. The more-likely culprit: dust.
Then there is the mysterious deep-space flashbulb called FRB121102—a fast radio burst first detected at the Arecibo telescope in Puerto Rico, November 2, 2012, and recorded more than 200 times since, including a dozen detections on Christmas Day in 2016.
A team of scientists cheerfully speculated that these erratic, super-powerful, millisecond-long blasts of radio waves—from more than three-billion light-years outside our galaxy—might be the long-awaited Contact: a radio beacon built by aliens to power a gargantuan light-powered sailing craft.
Now, new research, published January 10 in the journal Nature, begins to unravel the origin and nature of these bizarre bursts of energy that, in the blink of an eye, emit far more energy than our sun does in 24 hours. The study points away from extraterrestrial spacecraft and toward more natural explanations, like a neutron star near a black hole, a highly magnetized pulsar-wind nebula, or perhaps the remnants of an exploded star.
Whatever the cause, fast radio bursts may be the hottest and deepest mystery in astronomy today—and Casey Brinkman, University of Vermont class of 2017, was a co-author on the new Nature study, the only undergraduate student on the team.
A physics major at UVM, she focused on astronomy and astrobiology with UVM professor Joanna Rankin and visiting astronomer Dipanjan Mitra, studying an exotic type of star called a pulsar—including two trips with Rankin to study them at the Arecibo telescope. This background helped her land an internship this year—looking for aliens—and a role in the new study.
We spoke with Brinkman, a few days before the paper in Nature was released, about her love of astronomy and how she’s planning a career searching for signs of extraterrestrial life.
A lot of college students wonder what they’ll do after graduation. Tell us what you’re doing.
When I graduated from UVM, I went to do an internship at UC Berkeley—at the Berkeley SETI Research Center. SETI stands for the search for extraterrestrial intelligence. I’m searching for aliens—but not in the X-Files kind of way, more in the Carl Sagan kind of way.
How did you get to be a co-author on this new Nature study?
I work for a postdoctoral researcher who studies fast radio bursts. Those are hot stuff in astrophysics right now because we really have no idea what they are.
When we observe these radio bursts from different stars, we first check a pulsar in order to verify that what we think we are seeing is correct. If the pulsar data comes back with the exact right intensity and polarization then we know that the machines—the telescopes—were working properly that day.
And that's how I ended up getting on this new Nature paper: because of my experience with UVM professor Joanna Rankin, I knew about pulsars and how to measure them. My job was, basically, a calibration of pulsar data we had from the Green Bank Telescope, in West Virginia, to make sure the fast radio bursts weren’t just some kind error. We don’t want to come forward saying, “we found the salient signal around the star,” when really it’s a fault of the machinery. CERN did something like that a few years ago, saying that neutrinos are faster than light. But it was a measurement error. We’re trying to avoid measurement errors with aliens!
Could these fast radio bursts be from aliens?
Not likely! Our study doesn't say anything about that. The big reveal in this paper was about this fast radio burst’s polarization, which is something that people haven't been able to measure very well in the past because the bursts are so quick. We didn't put forth a strong theory of origin, but we precisely measured the polarization and a thing called the “Faraday rotation measure” which basically is talking about how the overall source is moving relative to us.
The new findings help us understand that this radio burst is an extremely dynamic source, that’s moving a lot, and that it comes from a strong magneto-ionic environment, which is the source of the polarization. The fact that it’s polarized tells a lot about the type of event that created it—in a crazy-strong magnetic field. We do put forth that, because the bursts were so short, they might be from a neutron star. That's one of the least cool ways to explain it, but it's one of the most-sound ways to explain it, unfortunately!
You’re an intern at an institution that has a mission to discern if and where extraterrestrial intelligence might be lurking. What’s that like?
It’s very interesting to go from studying pulsars, which the vast majority of the public doesn't know or care about—to aliens. The Berkeley SETI Research Center is committed to science and to thorough research methods—and to not jumping to any conclusions before there is very strong data. We survey in the neighborhood of 100 million of the nearest stars and then focus on stars that we think might have habitable exoplanets. But we do scan of a lot of different stars, just looking for any type of radio signals, very similar to the movie Contact. We observe things that, in the media, get blown up to: “this could be aliens!” like the Tabby’s Star and the bizarre asteroid that came through our solar system recently. Are we looking for the possibility of ET? Yes, but the people at Berkeley do a great job of not leaping to any conclusions, though we have a fridge in the lab with a bottle of champagne reserved for when we find aliens.
Do you feel confident that there is extraterrestrial intelligence in the universe?
Mathematically speaking, there's almost no way that we’re alone in this universe. That's what really drew me to SETI. There are hundreds of billions of stars in our one galaxy. Even if one percent of those has planets that are habitable and one percent of those have life, that’s still thousands of civilizations that could be out there.
Philosophically, we can ponder what it might take for civilizations to emerge and evolve—versus just life. But with the abundance of different types of situations that could be out there, and with the prevalence of organic molecules— we’re learning more and more about how prebiotic materials, just a step below amino acids, are formed everywhere in space—I think it's really unlikely that were alone.
What about the counterpoint that if there are the conditions for life in such a vast stretch of universe, how come we haven't heard from anybody yet?
That's the classic Fermi paradox. There are a number of ways that can be explained. What seems the most likely to me is that we only have a tiny scope of understanding. We've just barely started to explore our nearby universe, outside of our solar system.
Jill Tarter, one of the founders of the SETI Institute (and Carl Sagan's bestie), said what we've done so far in searching for extraterrestrial life—which we've only been doing for 50 years with limited tools—is similar to dipping a Dixie cup into the ocean, looking at it with your bare eye, and then saying, “there's no life in the ocean.” When, really, there are giant whales out there that you can see without a microscope, and also millions of microbes in that cup that we don't have the ability to see yet.
If and when we make contact, what will that mean for humanity?
Oh my God. I think it will bring up philosophic revolutions. I've always been of the mindset that humanity, and our place in the universe, is a very small part, but I think that's a very foreign mindset for a lot of people. I think the confirmation of alien life will push the worldview that the universe is a lot larger and stranger—and we are less important—than we often think.
What's next for you?
I'm currently applying to graduate schools for Ph.D. programs that focus in astrobiology, and solar system and planet formation, because that’s the really important science you need to understand in trying to look for life out there.
I understand you’re at home, in Vermont, now, working remotely with the team at Berkeley.
Yes, we’re pretty good at remote communication! It's not a fat paycheck, but it’s pretty insane that I’m getting paid to look for aliens.
Homepage photo: A cosmic cloud by Andrew Campbell via nasa.gov