Pluto's Geology Is Unlike Any Other
Take a pinch of Mars, a sprinkle
of Saturn’s moon Iapetus and a dash of Neptune’s moon Triton—and the
recipe will yield something like Pluto.
The first published
scientific findings from NASA’s New Horizons mission, which flew past
Pluto in July, confirm that the dwarf planet does not resemble any other
single world in the Solar System. Instead, its wildly varying terrain
is a crazy quilt of geological patterns and textures—copied, pasted and
tweaked from other planets and moons.
Like Mars, Pluto has volatile
compounds that cycle between freezing onto the ground and sublimating
back into the atmosphere. Like Iapetus, it has stunningly bright terrain
juxtaposed with dark areas. And like Triton, it seems to have streaks
made by wind marring its icy surface.
Pluto’s geological activity is
driven both by heat leaking from radioactive elements in its interior—a
remnant of its birth more than 4 billion years ago—and by the volatile
compounds that flit between its surface and its atmosphere. As Pluto
moves away from the Sun in its 248-year elliptical orbit, temperatures
plummet and these compounds freeze out of the atmosphere and fall onto
the surface as frost. When Pluto warms up again, methane, nitrogen,
carbon monoxide and other chemicals transform directly from ice on the
surface into atmospheric gases.But I also think something else is going
on to generate the heat from below because some had suggested that Pluto
inner core would have run out radioactive compounds long ago!!
High-resolution
pictures from New Horizons’ cameras show the effects of this seasonal
process. The broad, bright plains known as Sputnik Planum seem to be
covered by nitrogen glaciers; these flow gloppily, and quickly erase
craters made by crashing asteroids. “Punching a hole in jello springs to
mind,”. “Everything suggests this ice is exceptionally soft”—making it
unique in the Solar System.
Next to the light-coloured Sputnik Planum
lies the dark, cratered, ancient-looking Cthulhu region. The craters
may be up to 4 billion years old, from a time when asteroids were
heavily bombarding the early Solar System.
The dark coating may be
methane that has gone through chemical processing in the atmosphere,
says Jeff Moore, a team member and planetary scientist at NASA’s Ames
Research Center in Moffett Field, California. Winds could transport it
towards the equator, where it would settle out, much as dusty winds
blowing across Mars deposit sand seas.
Other areas on Pluto seem to
be a mishmash of material that is neither bright like Sputnik Planum nor
dark like Cthulhu. “There’s a lot of stuff on Pluto that doesn’t look a
whole lot like anything else we’ve ever seen,”. That includes
‘snakeskin’ terrain that may have been sharpened into bladelike ridges
over time as material froze and then sublimated away.
Many of the
general themes of Pluto discoveries have already been revealed in New
Horizons press briefings, but today’s paper, published in Science, is
the first formal record of the mission’s scientific results. It includes
details as seemingly mundane as Pluto’s size—2,374 kilometres across,
plus or minus 8 kilometres—that other scientists can use to refine their
understanding of properties such as heat flow within the dwarf planet.
Mission
scientists also found that Pluto is as close to perfectly spherical as
New Horizons’ instruments could possibly measure. This suggests that
during its early development, the dwarf planet was warm, squishy and
mouldable enough to avoid locking into a deformed shape.
Although
much of the data from New Horizons still remains to be radioed back,
“everything is coming together”,. “We have a much better set of
hypotheses for many places on Pluto than we had two months ago.”
Pluto
like said above is going into wintertime this when the "air" will
freeze on to its surface.I would have love to see Pluto during its
summertime.Maybe one day they will have a probe ready to orbit it during
this summertime!
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