Pluto seen by Hubble and New Horizons
This comparison shows the appearance of Pluto as derived from Hubble Space Telescope images in 2002–03 (left) against New Horizons' observations (right).
Hubble: NASA / ESA / M. Buie; New Horizons: NASA / JHU-APL / SWRI (courtesy Scott McCartney)

After a journey lasting nine and a half years, NASA's New Horizons spacecraft finally reached the distant world of Pluto. The three-billion-mile expedition culminated with New Horizons sweeping a mere 7,800 miles above Pluto's surface.

During its flyby last month, the probe obtained a treasure trove of scientific data, snapping by far the most detailed photographs ever taken of this mysterious object and its several moons. Instead of a cratered, barren orb, as some scientists expected, Pluto appears to be a startlingly dynamic world with soaring mountains and smooth plains of exotic ices. More facts on Pluto will continue pour in from New Horizons well into 2016 as the spacecraft transmits all of its data back to Earth.

On August 26, New Horizons team members Richard Binzel (Kavli Institute for Astrophysics and Space Research at MIT) and Cathy Olkin (Southwest Research Institute), along with Kavli Prize Laureate Michael E. Brown (California Institute of Technology) joined The Kavli Foundation for a live discussion. These planetary scientists answered questions about the mechanisms that might be shaping Pluto's landscape and what this strange new world can tell us about the other bodies at the Solar System's fringes.

Pluto scientists

About the participants (left to right):

  • Richard Binzel is a Professor of Planetary Sciences and the MacVicar Faculty Fellow in the Massachusetts Institute of Technology's (MIT) department of Earth, Atmosphere and Planetary Sciences, and a member of the MIT Kavli Institute for Astrophysics and Space Research (MKI). He is a co-investigator on the New Horizons mission and has studied the Pluto-Charon system for 35 years.
  • Cathy Olkin is a Principal Scientist at the Southwest Research Institute (SWRI) and a deputy project scientist for the New Horizons mission. Her planetary science interests include the study of the icy surfaces and tenuous atmospheres of outer Solar System worlds.
  • Michael E. Brown is the Richard and Barbara Rosenberg Professor of Planetary Astronomy at the California Institute of Technology and the 2012 Kavli Prize Laureate in Astrophysics for his research on the Kuiper Belt. His research specialty is the discovery and study of bodies at the edge of the Solar System.
  • ADAM HADHAZY (moderator) – is a freelance science writer who chiefly covers astrophysics and astrobiology. He has a Master's degree in science journalism from New York University.


  • What has amazed each of you about the New Horizons data? (3:10)
  • What could be replenishing Pluto's atmosphere? (5:50)
  • Could internal heat from Pluto be contributing to its geological changes and if so, what is its source? (10:10)
  • Why don't we see as many craters on Pluto? (11:25)
  • What would it be like to ice-skate on Pluto? (13:25)
  • Could Pluto and its moon Charon have formed at a later date than the rest of the solar system? (15:45)
  • What will the New Horizons mission be able to tell us about other objects in the outer solar system? (17:30)
  • How can studying Pluto tell us about the origins of Earth and the inner solar system? (20:55)
  • Since Pluto is so seasonal is it possible that the Tombaugh Regio region would ever disappear? (22:15)
  • What data about Pluto are you eagerly awaiting? (26:40)
  • Just how different is Pluto's geology from earth? (28:50)


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