Thousands of exoplanets have been discovered, many orbiting within their stars' 'habitable zones,' where temperatures could allow for liquid water.

Space telescopes like Kepler and TESS have confirmed over 5,000 exoplanets, with thousands more candidates. A significant number of these are rocky planets found in the 'Goldilocks zone'—the range of orbits where a planet is neither too hot nor too cold for liquid water, a key ingredient for life as we know it, to exist on its surface.