New Horizons Probe Closes On Pluto And Spots Possible Polar Caps

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Photo: New Horizons, Pluto (NASA)
Artist's concept of the New Horizons spacecraft encountering Pluto and its largest moon, Charon.

After traveling for more than nine years, the New Horizons spacecraft is on its final approach to Pluto. Pluto is smaller than Earth's moon, and so far away -- 3 billion miles -- that until now, it's been known as just a speck of light, even when viewed from the Hubble Space Telescope.

pluto and charonThe New Horizons mission is providing a first close-up view of this distant object that scientists term a "dwarf planet." Early pictures from the space craft have shown all of Pluto’s five known moons and a bright area at Pluto’s pole that could be a polar cap. If so, it's likely made of frozen nitrogen instead of frozen water, according to the mission's principal investigator, Alan Stern of Southwest Research Institute in Boulder.

The mission has significant ties to Colorado. In addition to Southwest Research Institute, Ball Aerospace, United Launch Alliance, and faculty and students at the University of Colorado are involved.

The spacecraft is within 34 million miles from Pluto and closing. Its closest flyby on July 14 will take it within 8,000 miles of the dwarf planet. At that distance, if the probe were passing by Earth, it would be close enough to provide images of the skyscrapers of downtown Denver, the football stadium, and Platte River.

Stern spoke with Colorado Matters host Ryan Warner. Click on the audio link above to hear the conversation.