Whether life exists on other planets has long been a tantalizing mystery, one that science fiction authors and conspiracy theory message board posts have explored alike. But since the 1990s, when astronomers first discovered the existence of other planetary systems, what was once the stuff of fantasy has developed into a real research question—one-part astronomy, one-part philosophy—for scientists to test.
“We ultimately want to understand our place in the cosmos: Are we alone or is there life elsewhere?” says astronomer Benjamin Pope, NASA Sagan Fellow at NYU’s Center for Cosmology and Particle Physics and Center for Data Science. “These profound questions have a bearing on our origins, our future, and our possibilities.”
Pope’s interest in the existential shaped his career from the outset. Although he originally intended to study Classics in college, he ended up switching to astronomy to understand the even more ancient history of our world. “I was very interested in broad ideas about where we came from and who we are,” Pope says.
By focusing on exoplanets—or those planets that exist outside the solar system and orbit stars other than the Sun— Pope found an area of astronomy he feels is best suited to addressing his philosophical inquiries.
Searching for evidence of life on other planets starts with evaluating a few key factors. “We study exoplanet habitability as a first step towards finding life,” says Pope. “First, are planets with pleasant atmospheres and temperatures common? What are they like? And one day we'll be able to find out—do they harbor life?”
Given the distance between the Earth and other planetary systems, finding exoplanets in the first place requires high-tech code and high-grade equipment. Astronomers typically use telescopes to detect visible or infrared light from the star. But Pope and a team of researchers recently developed a new method for looking at radio emissions instead, which researchers had been trying to do for decades.
"Working with the Dutch national observatory ASTRON and New York’s Flatiron Institute, we were able to detect radio waves emitted by a nearby star magnetically connected to its planet and ruled out alternative explanations with optical telescope follow-up," Pope explains. "Planets in orbits like this receive similar amount of light from their stars as the Earth does from the Sun, so you might think they could be green and pleasant. The radio evidence, however, indicates that magnetic connection could be blasting the planet’s surface with hostile radiation—bad news if we were hoping to find life there."
The findings give Pope the feeling that he’s one step closer to addressing the deeper questions that first attracted him to astronomy. And the team plans to continue searching for radio signals from exoplanets to understand their usually harsh, irradiated environments.
“At a broader level, this is probably our first window into using radio processes to understand exoplanets,” Pope says. “People have been trying this for decades and we’ve found the first objects. It’s not that we’ve got a new way of detecting planets, it’s that we have a new way of understanding them.”