NASA’s New Horizons spacecraft zipped past Pluto at nearly 7:50 a.m. EDT today, arriving 72 seconds earlier than anticipated and missing its target point by about 45 miles (70 kilometers) — well not bad at all after a 9.5-year, 3-billion-mile (5 billion km) voyage and well inside the probe’s target region. Principal Investigator Alan Stern directed a big group of scientists, enthusiasts, and media assembled at the site of mission operations at Johns Hopkins University Applied Physics Lab in Laurel, Maryland, in a countdown to flyby. As New Horizons flew past Pluto’s surface, it accomplished a closely choreographed series of tactics to pick up info as much as possible about the world and its five moons, as well as enormous Charon. But the spacecraft wasn’t done yet. As it flew behind the Pluto system, it looked back at both Pluto and Charon as they passed first in front of the Sun and then Earth. These observations will show the most complex data for studying the structure and density profile of Pluto’s atmosphere and for seeing whether Charon has an atmosphere at all.
After asking multiple times, Stern disclosed that it certainly looks like it snows on Pluto. But group member Fran Bagenal joked that it wouldn't be a good area for skiing because the snow would be too hard-packed. Deputy Project Scientist Cathy Olkin explained some of the features observable on the best single full-disk image of Pluto the spacecraft will return. She pointed out at least three linear structures located in Pluto’s north polar region, hummocky and mountainous land, craters, the bright area the group has nicknamed the “heart,” and the dark material that covers much of the planet’s equatorial region. Numerous of these features propose Pluto has been geologically active in the not-too-distant past (a billion years or so), but the researchers have yet to discover a smoking gun verifying current activity.
False-color compositional pictures released in the afternoon displays the two worlds are really complex. New Horizons Co-Investigator Will Grundy says the group is working as fast as possible to categorize the different substances the data discloses on the two surfaces. Most fascinating at the moment, however, is that Pluto's "heart" shows two very different colored areas. No doubt plenty more astonishments await in the days, weeks, and months ahead.