Three decades ago, the discovery of the first planet outside the solar system launched a new field: exoplanet astronomy. It also energised the search for life beyond Earth. Since then, more than 5,500 exoplanets have been identified. Scientists believe there could be trillions more—and experts and amateurs alike are trying to locate them. How will the discovery of these new worlds shape scientists’s understanding of how the solar system (and life) evolved?

Alok Jha, The Economist’s science and technology editor, talks to Jessie Christiansen, lead scientist of the NASA Exoplanet Archive at the California Institute of Technology.

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