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The images illustrate some basic new knowledge about the planet. For one, scientists have now identified the planet’s poles, based upon its rotation. While scientists had had a very rough vague idea of Pluto’s rotation and inclination beforehand, they have now pinned it down pretty precisely.
The images also show the planet’s most striking and unique features, though not with enough resolution to tell us what they are.
New color images from NASA’s New Horizons spacecraft show two very different faces of the mysterious dwarf planet, one with a series of intriguing spots along the equator that are evenly spaced. Each of the spots is about 300 miles in diameter, with a surface area that’s roughly the size of the state of Missouri.
Scientists have yet to see anything quite like the dark spots; their presence has piqued the interest of the New Horizons science team, due to the remarkable consistency in their spacing and size. While the origin of the spots is a mystery for now, the answer may be revealed as the spacecraft continues its approach to the mysterious dwarf planet. “It’s a real puzzle—we don’t know what the spots are, and we can’t wait to find out,” said New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder. “Also puzzling is the longstanding and dramatic difference in the colors and appearance of Pluto compared to its darker and grayer moon Charon.”
This image release also shows us what we will and will not see during the fly-by. The image on the left is the “encounter hemisphere.” This is the hemisphere that will be in view during New Horizons’ July 14 fly-by. We shall get very nice high resolutions of much of this hemisphere.
The other hemisphere, however, will not be facing us during the fly-by. Unless that can get some high resolution images before it rotates out of view, the row of large dark spots at the equator will remain a mystery.
The images also suggest that, because of Pluto’s tilt, much of the southern hemisphere is not going to be seen at all. It will remain an additional mystery for the many decades that are going to pass before another spacecraft finally returns to this distant place.