While today's Bastille Day celebration in France is marked by the 100th anniversary of the beginning of World War I, next year we can look forward to an even rarer event - our first ever flyby of the dwarf planet Pluto. That's right, we're within a year now of finally unlocking the secrets of this mysterious world!
Launched back in January of 2006, New Horizons has now spent the last eight years hurtling towards Pluto with unprecedented speed. Onboard are seven scientific instruments designed to revolutionize our view of this icy world and its curious moons. Once considered the last of the planets, scientists now consider Pluto the closest of an enigmatic population of icy bodies known as the Kuiper Belt. With other discovered Kuiper Belt objects orbiting even farther away, Pluto represents our best chance to understand what these worlds look like and how they behave. At stake is the validity of our solar system formation models, which must make predictions not only about the genesis of the planets, but also the asteroids, comets, and Kuiper Belt objects.
Feeling a bit impatient? Don't worry, we won't have to wait a full year to start making new discoveries! Starting next May 5th (what is it with this mission and holidays?), New Horizons will begin to make observations better than the Hubble Space Telescope can. This will be our first opportunity to glimpse Pluto as never before seen.
Still not soon enough for you? I applaud your eagerness! One other body in the solar system may provide us with some hints of what may await on Pluto. Neptune's largest moon Triton is believed to be a Kuiper Belt object like Pluto, captured early on in the history of the solar system. In 1989, the Voyager 2 spacecraft flew by the moon on its way out of the solar system and studied about 40% of its surface. The results were astonishing: Triton's frozen-nitrogen surface seemed among the youngest in the solar system and plumes of vapor were seen drifting across its surface. Not bad for perhaps the coldest moon in the solar system! Much of what we imagine Pluto to be like today is informed by these observations and, likewise, New Horizon's observations of Pluto promise to shed some light on the enduring mysteries of Triton.
You don't have to wait for next summer for some more exciting spacecraft action, though. In just over a month, ESA's Rosetta spacecraft will approach comet 67P/Churyumov–Gerasimenko in preparation for a November landing. When combined with Cassini's studies of Enceladus, Hubble's search for plumes on Europa, and New Horizon's upcoming visit to Pluto, Rosetta will mark yet another step in the exciting study of our solar system's icy bodies!