When the New Horizons spacecraft launched toward Pluto in 2006, no one knew that the tagline “the first mission to the last planet” would be short-lived. However two weeks earlier Eris, an icy body 30 percent more massive than Pluto had been discovered and ended Pluto’s then 76- year reign as the most distant planet in our solar system. Subsequently Pluto would lose its planetary status. Pluto is tiny and far away to see in more than the fuzziest of detail from here on Earth.
New Horizons was designed to bring clarity. For the past nine years it’s been speeding across the 3 billion miles between Earth and Pluto, and in July it finally reached its target. The spacecraft carried infrared and ultraviolet cameras and high-energy particle collectors, among other tools. As it sailed past at 31,000 mph, it captured images of Pluto and its moon, Charon, in more detail than anyone has ever seen. With just a little imagination, the lovable Disney canine character could even be inscribed on the surface!
When the mission was first conceived, astronomers thought of Pluto as a bit of an anomaly. It is tiny, for one, with an icy, rocky surface—a stark contrast to the giant, gaseous planets that orbit nearer to the sun. But since the launch we’ve learned much more about Pluto and its environs. And rather than the exception, it seems to be the rule.