LAUREL, Md. — NASA's New Horizons probe hasn't even had a chance to send its best stuff back to Earth yet, but an analysis of color imagery and other data transmitted before Tuesday's flyby has already yielded surprising findings about Pluto and its biggest moon, Charon. Here are five revelations to keep an eye on:
1. Pluto's surface composition is amazingly diverse: The New Horizons spacecraft snapped a three-filter color picture using its Ralph imaging instrument, and the science team exaggerated the color differences to accentuate differences in surface material and features. The result? "A very psychedelic image" of Pluto, in the words of deputy project scientist Cathy Olkin of the Southwest Research Institute. That suggests there's more surface variation than might have been expected.
2. Pluto's 'heart' is broken in two: The same Ralph imagery strengthens the case for saying that one of Pluto's most prominent features, a bright heart-shaped region, is actually made up of two dissimilar halves. The western half is smooth and icy, while the eastern half is peppered with craters — some of which may be several billion years old, said Jeff Moore of NASA's Ames Research Center. "The 'heart' actually is of two different beasts," he said.
3. Charon's 'dark pole' is dark red: The false-color view of Charon reveals that the mysterious "dark pole" feature spotted in previous imagery has more of a reddish cast than the lighter-colored material surrounding it. This suggests that material is falling to the surface there and is subsequently being broken down by ultraviolet radiation to produce carbon-containing compounds known as tholins. That's the same stuff that makes Pluto look reddish-brown.
4. Charon may be picking up some of Pluto's atmosphere: Scientists suspected this might be the case, but the reddish material supports the idea that molecules escaping Pluto's atmosphere may be settling around Charon's dark pole. Lowell Observatory's Will Grundy suggested that the dark pole could be a giant impact basin, and John Spencer of the Southwest Research Institute saw signs that "internal forces have fractured the surface" of Charon. But all these hypotheses will need to be tested once more detailed readings come in.
5. Scientists are already starting to name things: A map of Pluto showed that the names of underworld denizens have been informally associated with the dwarf planet's whale-shaped feature and other dark spots along the equator. The "whale" is nicknamed Cthulhu, after the dark god from H.P. Lovecraft's horror stories. Another spot is called Balrog, after the fiery demon from J.R.R. Tolkien's "Lord of the Rings" trilogy. Other spots are labeled Meng-p'o, Krun, Ala, Vucub-Came and Hun-Came — after underworld figures from Chinese and Maya mythology as well as Mandaean and Nigerian Igbo beliefs.
Such names have been given only provisionally, pending approval from the International Astronomical Union. They come from a list that was drawn up by the New Horizons team as part of a public outreach campaign.
Deputy project scientist Kimberly Ennico Smith of NASA Ames explained that the working names are used merely to assist with conversation. "Cannot just say 'that dark spot.' ... 'No, I meant that dark spot,'" she explained in a tweet.
The names — and many of the other new things reported by the New Horizons team — could well be revised if and when the spacecraft sends additional observations back to Earth.
"This is what you face when you see a new world for the very first time," Ennico Smith wrote. "We are all living this today."
