Jacob Bean is on the hunt — for exoplanets — and the associate professor at the University of Chicago is using an innovative instrument he and his team spent nearly a decade perfecting to find them in other solar systems.
Bean, a 1998 graduate of Murray County High School, and his team developed the MAROON-X over the course of nearly a decade, and earlier this year they attached it to a telescope at the Gemini Observatory at the top of Mauna Kea, Hawaii. Bean's research focuses on discovering and examining planets in other solar systems that could potentially sustain life, so he was a natural fit for this project.
As advances in technology allowed scientists to begin detecting very faint signatures from planets orbiting other stars in faraway solar systems, a burst of discoveries followed, with NASA currently listing 4,000 confirmed exoplanets — a planet that orbits a star outside the solar system — and thousands of other candidates, but, at this time, no Earth-like exoplanets with surface conditions hospitable for life have been found, according to the University of Chicago. Scientists must use indirect techniques to locate inconspicuous exoplanets, and the MAROON-X is able to pick up on the miniscule gravitational tug — which causes a star to wobble slightly in its orbit — an exoplanet exerts on the star as it orbits around it.
Michel Mayor and Didier Queloz were awarded the Nobel Prize in Physics this year for their 1995 discovery of 51 Pegasi b, the first exoplanet to be discovered orbiting a main-sequence star, and during the past 25 years, the field has only grown in popularity, with the likes of Bean looking to build on those early finds, said Bean, an associate professor of astronomy and astrophysics at the University of Chicago. As an undergrad at Georgia Tech, Bean planned to focus on cosmology — the science of the origin and development of the universe — but soon realized "that's a much more mature area" than exoplanet research.
"We know a lot about cosmology already," but, by studying exoplanets, "you had a chance to make big discoveries, and it's just so interesting," he said. Furthermore, "what sets us apart from other types of science is this work can help us understand ourselves, (as) whether life is present on other planets is a fundamental human question."
Despite the inherent value of this research, procuring funding for the MAROON-X project was actually Bean's highest hurdle.
In the U.S., funding for "ground-based astronomy," like the MAROON-X, pales in comparison to space-based astronomy, he said. Europe, in contradistinction, "does this way better than the U.S., and they have an integrated system of ground-based astronomy" that has led to numerous pivotal discoveries.
"We have more good ideas than money to fund them, and I think that's unfortunate," he said. "We lose a lot of very smart people who could do great things in science to Silicon Valley or Wall Street" due to monetary considerations.
Fortunately, Bean was able to land funds from his own university and other private philanthropic organizations "who recognize how important this is," he said. "Our federal government should be investing in this, because it can improve our everyday lives, our society, and even our national defense."
Attached to the Gemini North telescope, MAROON-X "takes all the light gathered by the 25-foot telescope and focuses it down to a spot that is the width of a human hair," according to the University of Chicago. It then "separates out that light into the different colors of the rainbow and reads the intensity of each band," with the color of the light changing slightly as the star moves forward or back — movements that allow scientists to calculate the mass of the hidden planet pulling on said star.
On Sept. 23, MAROON-X took its official first-light readings, and the instrument will work in concert with NASA’s Transiting Exoplanet Survey Satellite (TESS) to get a full picture of possible exoplanets, according to the University of Chicago. "TESS looks for the dimming of the light as a planet crosses in front of a star," so scientists can understand its size, and by combining that with the mass data gleaned from MAROON-X, one can calculate the density of a given exoplanet.
"We want to measure masses for quite a number of exoplanets," Bean said. "You can learn about underlying scientific truths by comparing" data.
TESS is a NASA Astrophysics Explorer mission led and operated by the Massachusetts Institute of Technology and managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, according to NASA. During a "two-year survey of the solar neighborhood, TESS is monitoring the brightness of stars for periodic drops caused by planet transits," the University of Chicago said, and TESS is expected to find some 20,000 exoplanets.
In addition to TESS, MAROON-X will also operate in concert with the James Webb Space Telescope, which is scheduled to launch in the spring of 2021 and be NASA's successor to the famed Hubble Space Telescope, Bean said. The James Webb will, among other contributions, provide information on the atmospheres of exoplanets.
"What makes Earth special is its atmosphere," Bean said. Consequently, it's paramount to ask, "Can the atmosphere (of a given exoplanet) support life, or would it be completely hostile to life?"
Bean hopes to find rocky terrestrial planets similar to Earth that could sustain life.
"Even in our own solar system, we have all different planets," he said. "We have rocky ones, like Mars and Earth, icy planets, like Uranus and Neptune, and gas giants, like Jupiter and Saturn."
The Gemini Observatory consists of twin optical/infrared telescopes located on two of the best observation sites on the planet, mountains in Hawaii and Chile, according to the Gemini Observatory website. Gemini is operated by a partnership of six countries, including the United States, and any astronomer in those nations can apply for time on Gemini, which is allocated in proportion to each partner's financial stake.
Because it's so widely used, Bean and his team don't have a monopoly on the instrument by any means, and they've returned to Hawaii this month to dive into additional scientific observations, he said. The vast preponderance of projects of this nature are "very long term," and this is no exception, so "we have a long future in front of us (as) we'll probably use (MAROON-X) for a couple of decades."
While their work is nowhere near complete, "it was a very special moment when we got that first observation of a star in the sky" with MAROON-X, he said. "A lot of what I do can seem really abstract, but to bring something physical together was really rewarding."
Bean is the son of two public school teachers, and his father was a science educator, so "I grew up in a science household," he said. "I always wanted to be a scientist, and, if you told my teachers what I do now, they wouldn't be surprised."
While some of the bright minds Bean meets in the scientific community attended elite private schools and/or grew up in privileged circumstances, that's by no means a prerequisite to this work, as he and many others can attest.
"I work with some of the smartest people in the world, and they are from all different backgrounds, so there's no reason someone from (north Georgia) can't go accomplish really big things," Bean said. "If you want to try to do something big, you should dream big, and you should go for it."