Which space telescope was responsible for discovering many exoplanets by the transit method before its retirement in 2018?

Which space telescope was responsible for discovering many exoplanets by the transit method before its retirement in 2018?

• A. Kepler Space Telescope
• B. Hubble Space Telescope
• C. Spitzer Space Telescope
• D. James Webb Space Telescope

Answer: (A)

The main idea tested is how the transit method works and why a mission designed to monitor many stars over a long time can discover many exoplanets. The Kepler Space Telescope was built to watch a fixed patch of the sky continuously for years, measuring the brightness of tens of thousands of stars with extraordinary precision. When a planet passes in front of its star, the star’s light dips very slightly and briefly; by catching these dips repeatedly, Kepler could confirm planets and determine their sizes and orbital periods. This approach led to the discovery of thousands of exoplanets, more than any other mission, before it was retired in 2018 due to fuel depletion. Other telescopes played important roles in exoplanet science, but Kepler’s dedicated, long-duration, wide-field transit survey is what produced the large number of discoveries.

The main idea tested is how the transit method works and why a mission designed to monitor many stars over a long time can discover many exoplanets. The Kepler Space Telescope was built to watch a fixed patch of the sky continuously for years, measuring the brightness of tens of thousands of stars with extraordinary precision. When a planet passes in front of its star, the star’s light dips very slightly and briefly; by catching these dips repeatedly, Kepler could confirm planets and determine their sizes and orbital periods. This approach led to the discovery of thousands of exoplanets, more than any other mission, before it was retired in 2018 due to fuel depletion. Other telescopes played important roles in exoplanet science, but Kepler’s dedicated, long-duration, wide-field transit survey is what produced the large number of discoveries.