What Are Exoplanets? Explained Simply

The habitable zone is the distance from a star where temperatures are just right for liquid water to exist on a planet’s surface—a key factor for potential life.

An exoplanet is a planet that orbits a star outside our solar system. Thousands have been discovered since the first confirmed detection in the 1990s, revealing an incredible diversity of worlds beyond our Sun.

A super-Earth is a planet that is larger and more massive than Earth, but still smaller than gas giants like Neptune. These planets may be rocky, gaseous, or a mix of both.

Kepler-186f was discovered by NASA’s Kepler Space Telescope and is one of the first Earth-size exoplanets found within its star’s habitable zone, making it a strong candidate for supporting life.

The detection of water vapor is important because it suggests the planet has a complex atmosphere and possibly the right conditions for life if other factors like temperature and pressure are suitable.

Astronomers use all of the above methods to detect exoplanets. The transit method, however, is the most widely used—it measures tiny dips in a star’s brightness when a planet passes in front of it.

Most gas giant exoplanets have atmospheres dominated by hydrogen and helium, similar to Jupiter and Saturn in our solar system.

HD 80606 b is famous for its highly eccentric orbit, which causes extreme temperature swings as it moves close to and far from its star.

Astronomers study exoplanets to understand how planets form, evolve, and differ from those in our solar system. These studies help scientists learn about Earth’s origins and the potential for life elsewhere in the universe.

TESS (Transiting Exoplanet Survey Satellite) is designed to search for Earth-like exoplanets around nearby stars using the transit method. It has discovered thousands of exoplanet candidates since its 2018 launch.