On May 28, 2026, Liberty Science Center hosted Dr. Josh Winn, professor of astrophysics at Princeton University and author of The Little Book of Exoplanets, for our latest Space Talk presentation: Little Talk of Exoplanets.

Since 1992, astronomers have discovered more than 6,000 exoplanets in our galaxy, planets that orbit stars outside of our solar system. Each of them is unique, and it is the job of astronomers like Dr. Winn to find, study, and understand them. During his Space Talk, Dr. Winn took viewers on a journey through the Milky Way in the country’s largest planetarium to explore some of the planets we have discovered and how we learn about them.

Most exoplanets that we have discovered have been found using what is known as the transit method: watching distant stars and waiting for small dips in their brightness as a planet passes in front of it, blocking some of the star’s light. Space telescopes like the now-retired Kepler and the currently active TESS telescope study huge numbers of stars to find as many of these transits as possible. From their observations, we can learn the size of a planet, how far it orbits from its star, how long that orbit takes, and even what that planet is made of.

We first visited Wasp-12b, a planet studied nearly twice the size of Jupiter but that orbits just 2.2 million miles, just 2% of the distance that our Earth orbits the Sun. At this close distance, the planet has a surface temperature of more than 5,000 °F and is slowly being consumed by the star’s gravity.

We also had a chance to visit Kepler-1647b, a planet that feels more at home in science fiction than in our reality. Unlike our solar system, which has just one star at the center, this solar system has two stars orbiting each other at its center with one lonely gas giant planet about the size of Jupiter traveling around them. The view from the atmosphere of this planet, or from any moons around it, would resemble the view Luke Skywalker had of his two suns on Tatooine in Star Wars.

One of the biggest goals of exoplanet scientists is to find a planet that could host life. To find that, astronomers first look for planets at the proper temperature to have liquid water on its surface. A planet too close to its star, like Wasp-12b, is so hot any liquid water would evaporate while a planet too far away would have any water present frozen as ice. One of the promising systems to find a planet like this is the Trappist-1 system, a smaller red dwarf star that features seven planets orbiting it. Four of these planets are at the correct distance to potentially host liquid water, but to know for sure if there are any planets out there with liquid water we need more advanced tools to study these planets even better.

The James Webb Space Telescope (JWST), which focuses more on deeply studying already discovered exoplanets, has made huge strides in observing the composition of exoplanets. Additional telescopes like the Nancy Grace Roman Space Telescope, launching as early as September 2026, will likely discover around 100,000 new exoplanets. These can be studied in more detail by JWST and future planned space telescopes like the Habitable Worlds Observatory.

We thank Dr. Winn for joining us for his second Space Talk! Join us next month on June 25, 2026 when we will welcome Karen Lloyd, Wrigley Professor of Earth Sciences, and Marine and Environmental Biology at the University of Southern California and author of Intraterrestrials: Discovering the Strangest Life on Earth.

Learn more about Space Talk here.