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Finding planets around stars other than our Sun is a difficult task. The most successful detection method looks for the small periodic motions of the parent star caused by the planet's gravity. Since the effect is larger for massive Jupiter-sized planets, smaller Earth-sized planets are hard to find. Nevertheless, the smallest exoplanet discovered by this technique is only one and a half times the size of the Earth and just five times as massive. In the future, new space missions will improve our ability to find ever smaller and more distant planets.