Far from being a bland, uniform surface, the dwarf planet seems to play host to a complex array of geological features that planetary scientists are already trying to decipher.
“We’re close enough now that we’re just starting to see Pluto’s geology,” said Curt Niebur, New Horizons program scientist at NASA Headquarters in Washington, D.C., in a Friday news release.
Of particular interest is the “whale” feature that can be seen covering the lower-left region of Pluto’s globe in this Long Range Reconnaissance Imager (LORRI) observation. Although it’s too early to tell, this dark shape seems to be some kind of plain, starkly contrasting with the surrounding, brighter landscape.
Niebur is particularly interested in the gray region immediately above the whale’s “tail”: “It’s a unique transition region with a lot of dynamic processes interacting, which makes it of particular scientific interest.”
“Among the structures tentatively identified in this new image are what appear to be polygonal features; a complex band of terrain stretching east-northeast across the planet, approximately 1,000 miles long; and a complex region where bright terrains meet the dark terrains of the whale,” added New Horizons principal investigator Alan Stern. “After nine and a half years in flight, Pluto is well worth the wait.”
The imagery coming from New Horizons is becoming more and more detailed as the probe approaches. This particular LORRI image was captured on July 9 from a distance of 3.3 million miles (5.4 million kilometers), but even from this distance the camera is able to deliver a resolving power of 17 miles per pixel.
In 2006, Pluto suffered what was widely regarded as a “demotion” of sorts, when it was re-catagorized by the International Astronomical Union (IAU) from being a “planet” to a “dwarf planet.” The motivation for this reclassification focused on the new and exciting Kuiper Belt discoveries that were cropping up as observational techniques became more sophisticated. Rather than the classical “nine planets,” astronomers found themselves swamped with a solar system possibly containing hundreds of planets.
Unfortunately for Pluto, it became a rounding error and fell into a new group of planetary bodies: dwarf planets.
Over the years, the “Pluto debate” has ebbed and flowed in the public and scientific arena with polarized opinions on both sides focusing on what is considered to be a planet and what isn’t. The definition of a planet (using the IAU’s golden rules for what a planet is) will, however, seem completely archaic when New Horizons beams back a growing archive of close-up observations of this alien world after flyby (the mission is expected to take months to transmit all of its Pluto close encounter data, according to Stern).
For what it’s worth, I think that we are currently exploring a completely different class of planetary body, not based on its physical size, but on its unique configuration. Largest moon Charon doesn’t orbit Pluto; Pluto and Charon orbit a common point (known as a “barycenter”) in space above Pluto’s surface. Charon’s mass is so large that on each orbit, it tugs Pluto off-center, causing it to wobble. As discussed in previous Discovery News articles, the case for the Pluto-Charon system being a “binary planet” is an interesting one.
Read more at Discovery News
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