The New Horizons spacecraft has returned a handful of close-up pictures of Jupiter and some of its moons after its closest approach to the giant planet on Wednesday.
The probe caught a picture of a dusty plume rising from a volcano called Tvashtar on Io, one of Jupiter鈥檚 larger moons. The plume reaches 240 kilometres (150 miles) above the moon鈥檚 surface (scroll down for more images).
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鈥淭his is the best image of a large volcanic plume on Io since the Voyager flybys in 1979,鈥� says John Spencer, deputy leader of the Jupiter encounter science team from the Southwest Research Institute in Boulder, Colorado, US. 鈥淚f the Tvashtar plume remains active, the images we take later in the encounter should be even better.鈥�
It also snapped the closest ever photograph of Jupiter鈥檚 Little Red Spot, a storm formed recently by the merger of three smaller white storms (see Red Spot Junior buzzes its big brother on Jupiter). In the latest picture, the Little Red Spot looks uncannily like its more famous sibling, the Great Red Spot, the largest storm in the solar system, which has been churning for centuries.
The icy moon Europa was another one of New Horizons鈥檚 early targets. The probe is looking for curious circular landmarks nicknamed 鈥渃rop circles鈥� on the moon. Because the large arcs and circles are faint, it helps to look for them when the Sun is casting long shadows over the icy terrain (see Passing probe to study 鈥榗rop circles鈥� on Europa).
Not to be forgotten, Ganymede, the solar system鈥檚 largest moon, makes an appearance in the early snapshots. It showed off ancient, dusty terrain as well as brighter young material and bright pockmarks left over from meteoroid impacts.
The composition of a large portion of the icy moon鈥檚 surface remains unknown 鈥� a situation New Horizons is expected to rectify.
Most of the data and images gathered by New Horizons will be returned to Earth in March and April so the probe can collect as much data as it can now before swivelling around to point its antenna back at Earth.
NASA鈥檚 New Horizons is ultimately heading for Pluto and other objects in the Kuiper Belt, a ring of icy objects in the outer solar system. After it passes Jupiter, it will fly down the planet鈥檚 magnetotail 鈥揳 region of sulphur and oxygen ions originally spewed out by Io (see Pluto probe finds surprises at Jupiter). The charged particles get trapped in the planet鈥檚 magnetic field, then blown by the solar wind into a tail that stretches hundreds of millions of kilometres behind Jupiter 鈥� practically to Saturn鈥檚 orbit.
