For centuries, scientists and astronomers hypothesized that planets orbiting other stars could exist outside of our own solar system. In 1992, the first exoplanets were confirmed. That discovery sparked questions about what these worlds are like and what they are made of.
Decades later, with advanced technology, there are several ways astronomers find these faraway worlds—one method is the transit method, that uses a star’s dimming and brightening to identify planets as they orbit in front of the star.
With new methods and techniques, thousands of exoplanets have been found, and astronomers continue to explore our universe to find more. Sara Seager is a professor at MIT, and on the front lines of exoplanet discovery. She said another way astronomers search the skies is with the James Webb Telescope.
“It’s literally taking us to the next level,” Seager said. “It is helping us study exoplanet atmospheres. There's so much going on...What appears to be the most common planet in our galaxy, as far as our telescopes allow us to determine, are planets between the size of Earth and Neptune for which there's no solar system counterpart. We don't know what they're made of. We don't know how they formed, and it's just crazily mysterious.”
Seager said it is an incredible journey and that said exoplanet discoveries are something out of science fiction when “we went from just having science fiction like Star Wars, Star Trek and other movies to then having real planets.”
In our own solar system, NASA last year sent a mission to Jupiter’s icy moon Europa. Scientists think there might be evidence of the building blocks for life on or beneath its surface – the findings might help scientists find signs of life elsewhere, including exoplanets.
However, Seager said while technology helps locate and study exoplanets, uncovering signs of life on distant worlds isn’t that simple.
“It's made more complex by the fact that what we can search for, in terms of a sign of life, can often be mimicked by other things like volcanos, lightning or meteoric delivery,” Seager said. So, it's very hard for us to say anything robust. But the good news is, there's more and more activity. There are more and more bodies in the solar system we think might harbor life, and exoplanet atmospheres are accelerating.”
Another hope of Seager’s is to find planets orbiting a star much like our own. However, she said the scientists would need to go above our planet with a special telescope to block out the sun.
With finding perhaps another group of planets orbiting a twin star to our own, Seager hopes we find “a true Earth twin, that's an Earth sized planet in an Earth-like orbiting a sun like star, that's an incredible challenge.”