It might seem like NASA is announcing a brand-spanking-new "Earth-like" exoplanetconstantly—some far-away world that might possibly maybe have the basic requirements for life as we know it. And it seems that way because, well, that's pretty accurate: it's all thanks to NASA's wildly successful Kepler Space Telescope, which uses the blinking and dimming of distant alien stars to spot planets that might orbit around them. But the latest Kepler finds (219 new planetary candidates, 10 of which are Earth-size and the right distance from their host star to hold liquid water) mark something of an end: this represents the final official planetary search results from Kepler's mission data.
Close your eyes and picture what the Earth looks like. You're probably picturing a circle, mostly blue thanks to the ocean, with swirls of clouds and the occasional green and brown land mass. The entire sphere is floating in a mass of impossible black. You're picturing Earth in a way that you've never actually seen with your own two eyes. Maybe you're getting the sketch from this famous shot, below, known as the blue marble image. Astronauts aboard the Apollo 17 space mission snapped the picture on December 7th, 1972. Countless other images of our home planet have been taken, which have forever shaped our imagination of it. Still, only a handful of humans have seen it with naked eyes.