We live in a golden age of exoplanet discovery. Not only are we searching for and finding new worlds around other stars all the time, but as our technology improves we are learning more about these exotic places and inexorably bearing down on the all important answer to the question of whether life elsewhere exists in our galaxy.
The next big milestone in our study of exoplanets is a telescope that can see beyond the limits of our eyes, beyond the boundaries of our solar system, beyond the frontiers of our knowledge. A telescope that can reveal the secrets of the stars and the mysteries of the planets. A telescope that can take us closer to finding another home in the cosmos. That telescope is the Nancy Grace Roman Space Telescope, a NASA observatory that is scheduled to launch in May 2027 and explore a wide range of astronomical phenomena, including exoplanets.
Observing planets around other stars is a difficult business, one that pushes the boundaries of our technology. Studying dim, small and elusive worlds to discover their potential for habitability requires novel techniques and state of the art telescopes.
To get the observations we need, the Roman Space Telescope will employ three techniques to study exoplanets: microlensing, direct imaging, and transit method. Each of these methods has its own advantages and limitations, and together they will provide a comprehensive view of the formation, evolution, and physical properties of planetary systems.
Microlensing looks for a tiny flash of light from a background star as a planet moves between us and the background star. This flash is a signal that betrays the existence of a relatively small, dark world.
The transit method looks for tiny dips in brightness as a planet blocks out part of the star’s light. These dimmings tell us a lot about the size of the planet, its orbit around the star and the length of its year.
Direct imaging is the holy grail, the new thing humanity can do. Planets are billions of times dimmer than their host stars, they are so bright we can’t see the planet directly unless we block it. To solve this problem, astronomers and engineers have been working on ways to take a direct look at small, Earth-sized worlds that lie hidden behind the glare of their star.
The Roman Space Telescope will demonstrate direct imaging technology that has never been flown aboard a space-based observatory before. Using this technology, Roman will help pave the way for future missions to image Earth-like planets around nearby stars and measure their spectra to search for signs of life.
By using these complementary approaches, Roman will provide the most complete picture yet of the diversity and complexity of exoplanets. Roman will also take us another step closer to discovering another “pale blue dot” — a habitable, Earth-like planet orbiting a nearby star.
This is not just science fiction. This is science fact. This is what Roman will do for us. This is why Roman matters. This is how Roman will help advance knowledge about exoplanets.