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3.3.9 The New Horizons mission

Figure 61 Global view of Charon and a close-up obtained at a range of only 79,000 km. 

Pluto’s moons were revealed in detail in 2015 when the New Horizons mission flew past Pluto. Launched in 2006, its journey to Pluto took nine years, and radio signals transmitted back to Earth took about three-and-a-half hours to reach us. It showed that Pluto’s landscape is unlike that of Triton, even though they have similar compositions. Charon has a mixture of cratered (old) terrain and smooth (young) terrain that might have been cryovolcanically resurfaced, and is cut by major fractures.

No new small moons were discovered. Here are views of Nix and Hydra shown at similar scales.

Figure 62 Nix (left), 42 km long and Hydra (right), 55 km long. The colour on Nix has been exaggerated to highlight an unexplained red area.

You can follow the mission at this link: New Horizons [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)]

In contrast to Pluto’s moons, about which we still know little, during the next three weeks you’ll be learning about the moon that we know most about – namely The Moon.


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