Which telescope is designed to scan the sky for transiting exoplanets?

• A. Hubble
• B. Spitzer
• C. TESS
• D. Kepler

Answer: (C)

Detecting transiting exoplanets relies on watching many stars over time for small, regular dips in brightness when a planet passes in front of its star. To find many such planets, a mission must survey large portions of the sky rather than focus on one target. The Transiting Exoplanet Survey Satellite is designed for this broad search: it carries four wide-field cameras that sweep across the sky, monitoring bright, nearby stars for transits in different sky sectors. This all-sky, transit-focused approach makes it ideal for discovering a wide range of exoplanets and providing targets for follow-up observations. In contrast, other telescopes are more targeted or specialized: Hubble studies specific objects in detail, Kepler looked at a single fixed field of stars for years, and Spitzer focused on infrared observations of known targets rather than conducting a wide transit survey.