Abstract

The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto’s tidal axis1 and may be an impact feature2, by analogy with other large basins in the Solar System3,4. Reorientation5,6,7 of Sputnik Planitia arising from tidal and rotational torques can explain the basin’s present-day location, but requires the feature to be a positive gravity anomaly7, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day8 and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent9, nitrogen loading and reorientation may have exhibited complex feedbacks7.

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Acknowledgements

New Horizons was built and operated by the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, USA, for NASA. We thank the many engineers, flight controllers and others who have contributed to the success of the New Horizons mission and NASA’s Deep Space Network for a decade of excellent support to New Horizons. We thank B. Johnson for discussions on impact physics and J. Conrad for cryovolcanism calculations.

Author information

Affiliations

  1. Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, California 95064, USA

    • F. Nimmo
    •  & C. J. Bierson
  2. Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA

    • D. P. Hamilton
  3. Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St Louis, St Louis, Missouri 63130, USA

    • W. B. McKinnon
  4. Lunar and Planetary Institute, Houston, Texas 77058, USA

    • P. M. Schenk
  5. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • R. P. Binzel
  6. National Aeronautics and Space Administration (NASA) Ames Research Center, Moffett Field, California 94035, USA

    • R. A. Beyer
    • , J. M. Moore
    •  & K. E. Smith
  7. Southwest Research Institute, Boulder, Colorado 80302, USA

    • S. A. Stern
    • , C. B. Olkin
    •  & L. A. Young
  8. Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723, USA

    • H. A. Weaver
  9. National Aeronautics and Space Administration (NASA) Ames Research Center, Moffett Field, California 94035, USA

    • J. M. Moore
    • , R. Beyer
    • , D. Cruikshank
    • , C. Dalle Ore
    • , O. L. White
    • , O. M. Umurhan
    • , C. Chavez
    •  & K. E. Smith
  10. Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St Louis, Saint Louis, Missouri 63130, USA

    • W. B. McKinnon
  11. Southwest Research Institute, Boulder, Colorado 80302, USA

    • J. R. Spencer
    • , M. Buie
    • , J. Parker
    • , S. Porter
    • , S. Robbins
    • , K. Singer
    • , B. Carcich
    • , C. Conrad
    • , C. Howett
    • , J. Kammer
    • , A. Parker
    • , E. Schindhelm
    • , A. Steffl
    • , H. Throop
    • , C. Tsang
    • , A. Zangari
    • , S. A. Stern
    • , C. B. Olkin
    •  & L. A. Young
  12. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • R. P. Binzel
    •  & A. Earle
  13. NASA Jet Propulsion Laboratory, Pasadena, California 91019, USA

    • B. Buratti
    •  & K. Runyon
  14. Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723, USA

    • A. Cheng
    • , J. H. Roberts
    • , O. Barnouin
    • , C. Lisse
    • , A. Marcotte
    • , M. Saina
    • , H. Winters
    •  & H. A. Weaver
  15. Southwest Research Institute, San Antonio, Texas 78238, USA

    • R. Gladstone
    •  & K. Retherford
  16. Lowell Observatory, Flagstaff, Arizona 86001, USA

    • W. Grundy
  17. University of Virginia, Charlottesville, Virginia 22904, USA

    • A. D. Howard
    •  & A. Verbiscer
  18. National Optical Astronomy Observatory, Tucson, Arizona 85719, USA

    • T. Lauer
  19. Stanford University, Stanford, California 94305, USA

    • I. Linscott
    •  & L. Tyler
  20. Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, California 95064, USA

    • F. Nimmo
  21. B612 Foundation, Mill Valley, California 94941, USA

    • H. Reitsema
  22. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA

    • D. Reuter
  23. Lunar and Planetary Institute, Houston, Texas 77058, USA

    • P. M. Schenk
  24. The SETI Institute, Mountain View, California 94043, USA

    • M. Showalter
  25. The Johns Hopkins University, Baltimore, Maryland 21218, USA

    • D. Strobel
  26. George Mason University, Fairfax, Virginia 22030, USA

    • M. Summers
  27. Planetary Science Institute, Tucson, Arizona 85719, USA

    • M. Banks
  28. University of Arizona, Tucson, Arizona 85721, USA

    • V. Bray
  29. Arlington, Vermont 05250, USA

    • A. Chaikin
  30. University of Maryland, College Park, Maryland 20742, USA

    • D. P. Hamilton
  31. Cornell University, Ithaca, New York 14853, USA

    • J. Hofgartner
  32. Space Telescope Science Institute, Baltimore, Maryland 21218, USA

    • J. Stansberry
  33. Roane State Community College, Oak Ridge, Tennessee 37830, USA

    • T. Stryk

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  1. New Horizons Geology, Geophysics & Imaging Theme Team

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Contributions

D.P.H. originated the reorientation hypothesis. F.N. developed the subsurface ocean scenario and carried out the bulk of the calculations. C.J.B. calculated the effect of realistic basin geometries and ejecta blanket. P.M.S. and R.A.B. provided the stereo topography. All authors read or commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to F. Nimmo.

Reviewer Information

Nature thanks G. Collins and the other anonymous reviewer(s) for their contribution to the peer review of this work.

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DOI

https://doi.org/10.1038/nature20148

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