might be related to the colder than expected upper atmosphere observed by New Horizons, and ‘has important implications for the volatile
recycling and long-term evolution of Pluto’s atmosphere.’
Like the Earth, Pluto has a long ion tail extending downwind beyond
for a distance of at least 400 Pluto radii (about half a million km). As for
the dust in the Pluto system which it was feared might be encountered,
only a very low density of particles – barely 1 micron-sized grain per km3
- was measured by the Student Dust Counter instrument.
Figure 20: New Horizons’ Solar Wind Around Pluto (SWAP) detector revealed interactions with the solar wind not dissimilar to those found at Venus and Mars.
Credit: NASA/JHUAPL/SwRI
Pluto in context – looking ahead
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What we have learned from New Horizons’ encounter with Pluto, its
moons and its interactions with the solar wind are obviously important
in the context of the other members of the Kuiper Belt. Scientists now
have a better idea of what they might discover out in the far reaches
of the solar system, and that they can expect to find a much more active population of worlds than previously imagined.
There were many who were upset at Pluto’s loss of planetary status
and so-called ‘relegation’ to the status of ‘dwarf planet’ in 2006. However, ongoing discoveries confirming the population and extent of the
Kuiper Belt have given it a much more interesting position for those
studying the nature and evolution of the outer Solar System
Of ‘dwarf planet’ classification as it relates to the Kuiper belt, Leslie
Young says ‘I don’t think it’s a useful term. It’s not used much at specialist level and I think it will die the death, especially as we begin to look
at the Kuiper Belt in more detail. We need a whole new way of defining
objects out here in the outer part of the solar system. We have Pluto,
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