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Houston Matters

Ten Things The New Horizons Mission Taught Us About Pluto

In January 2006, NASA launched the New Horizons probe into space to take a closeup look at Pluto. Now, we look back at its findings.

An image of Pluto captured by NASA’s New Horizons spacecraft.


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In January 2006, NASA launched the New Horizons probe into space on a trajectory towards Pluto to get an up-close look at the little-understood dwarf planet.

Nearly ten years later, in 2015, New Horizons reached its destination and went on a six-month flyby that captured the first-ever detailed images of Pluto, a landmark in space exploration.

NASA's New Horizons spacecraft launches on its mission to study Pluto on Jan. 19, 2006.

Chasing New Horizons - Book CoverNow, Space Center Houston is hosting a free event looking back at the mission with Dr. Alan Stern and Dr. David Grinspoon, who both collaborated on a book about the mission, called Chasing New Horizons: Inside the Epic First Mission to Pluto.

Houston Matters talks with Dr. Grinspoon about the mission’s findings, and what is in store for the probe's future as it flies farther into space.

Ten Things New Horizons Taught Us About Pluto:*

  1. The complexity of Pluto and its satellites is far beyond what we expected.
  2. The degree of current activity on Pluto's surface and the youth of some surfaces on Pluto are simply astounding.
  3. Pluto's atmospheric hazes and lower-than-predicted atmospheric escape rate upended all of the pre-flyby models.
  4. Charon's enormous equatorial extensional tectonic belt hints at the freezing of a former water ice ocean inside Charon in the distant past. Other evidence found by New Horizons indicates Pluto could well have an internal water-ice ocean today.
  5. All of Pluto's moons that can be age-dated by surface craters have the same, ancient age—adding weight to the theory that they were formed together in a single collision between Pluto and another planet in the Kuiper Belt long ago.
  6. Charon's dark, red polar cap is unprecedented in the solar system and may be the result of atmospheric gases that escaped Pluto and then accreted on Charon's surface.
  7. Pluto's vast 1,000-kilometer-wide heart-shaped nitrogen glacier (informally called Sputnik Planum) that New Horizons discovered is the largest known glacier in the solar system.
  8. Pluto shows evidence of vast changes in atmospheric pressure and, possibly, past presence of running or standing liquid volatiles on its surface – something only seen elsewhere on Earth, Mars and Saturn's moon Titan in our solar system.
  9. The lack of additional Pluto satellites beyond what was discovered before New Horizons was unexpected.
  10. Pluto's atmosphere is blue. Who knew?

*Source: NASA

An image of Pluto’s moon Charon captured by NASA’s New Horizons spacecraft on July 14, 2015.