A floating assemblage of zeppelin-like spheres on which passengers stroll for the duration of their travel. (Source)
NASA’s Kepler planet-hunting mission has spotted 2,326 likely worlds orbiting other stars, including a couple hundred about the size of Earth, and more are on the way. But moving them from the "likely" to "confirmed" column is slow and difficult.
That explains the apparent disconnect between Kepler deputy science-team leader Natalie Batalha mentioning almost casually, a couple weeks ago, that Kepler has found 207 Earth-size candidate planets (defined as no more than 1¼ times Earth’s diameter) — and the news that will be all over the world this afternoon that Kepler has just found the first two Earth-sized exoplanets ever. (Source)