New Horizons Spacecraft Captures Images of Charon in Orbit Around Pluto

August 13, 2014

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August 13, 2014 – The real story behind this most recent imagery of Charon circling in close proximity to its parent, Pluto, is just how little we actually know about the dwarf planet. Here is an astonishing reminder of our lack of knowledge. We humans have yet to observe a full year on Pluto. We’ve known of its existence since 1930 but the dwarf planet takes 248 Earth years to orbit the Sun. As a result we don’t, to date, have an accurate measure of Pluto’s complete orbital path.

New Horizons is about to be put to sleep on August 29th and will be reawakened on December 6th. So we won’t see any more pictures of Pluto at least not until the start of the New Year.

Charon and Pluto are often described as twin dwarf planets. That’s because Charon at 1,200 kilometers (750 miles) in diameter is proportionately larger than any other moon in the Solar System when compared to its parent planet. Pluto is 2,360 kilometers (1,466 miles) or about twice the size of Charon. And Charon exerts a gravitational pull on Pluto so strong that the two actually orbit around what is known as a barycenter, a point in space near the dwarf Planet. This is observed as a wobble (see artist illustration below)

Pluto’s other moons, Nix, hydra, Kerberos and Styx are much smaller in size and we know very little about them. For more Pluto facts you can check out this NASA site. And in eleven months our knowledge of Pluto, Charon and the baby moonlets will substantially increase when New Horizons makes its closest approach. It should be exciting to see both images and telemetry from this our furthest destination foray in the Solar System. Of course I’m not counting to the two Voyager spacecraft who after their Grand Tour of the outer Solar System have now moved on to the edge of interstellar space.