My previous post about the New Horizons flyby of Pluto was dated a few hours before the event of 14 July 2015. Communication with Earth by the spacecraft was turned off so it could execute a large number of commands during the few hours of flyby. The data is to be transmitted to Earth in the months to come. Late in the day, New Horizons phoned home to say it was healthy and did succeed in carrying out the commands. It continues to gather data and return data sets each day. Where is New Horizons now? It is coasting beyond Pluto into the Kuiper Belt. It has more work to do.
There are 50 gigabytes of data stored onboard. It will take 500 days to send it to Earth. People wonder why it will take so long? They want to see the results NOW! Here is the answer from a member of the team.
Pluto and Charon Views
The flyby has given mankind the first ever detailed views of Pluto and the largest moon Charon. Two images were used to make this composite. It shows them in true color and correctly positioned for size and distance apart as seen from the point of view of the spacecraft as it neared closest approach. Unless stated otherwise, all images in this post are credited to NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Click images for more detailed views.
Four images were combined to give this true color composite of Pluto. Notice the cratered darker regions and the smooth, un-cratered, light colored Tombaugh Regio. The heart shaped region was named after Clyde Tombaugh who discovered Pluto.
Charon shows surprisingly youthful terrain with craters, fractures, and light and dark variations. The dark patch is the north polar region. There are few craters indicating the surface has been reshaped over time by relatively recent geologic activity.
Surface Details on Pluto
Mountains as high as 11,000 ft (3,500 m) were revealed in this Pluto image about one hour before closest approach. The lack of craters and the smooth textures of some regions indicate their age to be about 100 millions years. This is youthful compared to the 4.56 billion year age of the solar system. Unexplained geological forces are actively reshaping the surface.
Looking closely at the lower left boundary of the heart shaped Tombaugh Regio, scientists noted two very different terrains. The light colored material on the right is composed of ices of cold gases. They form a sort of ice pack similar to our ice packs of the Antarctic or Greenland. They are not made of water ice. They are likely formed by a snow-like mechanism. These ices are able to flow more easily than water ice. These flowing glacier-like layers are encroaching on the older, darker, and heavily cratered terrain at the left. They filled in valleys and some of the craters in this view. The mountains in the top center are about the height of our Appalachians.
Looking Back Toward Sun
Mission controllers were able to direct New Horizons with incredible accuracy. After traveling since launch in 2006, it arrived on a trajectory that took it briefly into the shadow of both Pluto and Charon. The spacecraft turned to look back toward the Sun. Doing so allowed a silhouette view of each object in turn. Such a maneuver was designed to show the extent of any atmosphere around either object and analyze the contents. This is the view of Pluto in silhouette. This haze surprised scientists because of how high it extended…about 50 miles (80 km). They feel the need to modify their models significantly.
More to Come
The discoveries here are but a few of the early ones. Many more are coming in the weeks ahead. New images and measurements continue to downlink to Earth each day. What an exciting time for everyone. I will continue to post important updates. I encourage browsing the mission site by visiting this link. Mission details, images, multimedia, and more are available with more added each day.