Planetary science. Low-altitude magnetic field measurements by MESSENGER reveal Mercury's ancient crustal field

Catherine L Johnson; Roger J Phillips; Michael E Purucker; Brian J Anderson; Paul K Byrne; Brett W Denevi; Joshua M Feinberg; Steven A Hauck 2nd; James W Head 3rd; Haje Korth; Peter B James; Erwan Mazarico; Gregory A Neumann; Lydia C Philpott; Matthew A Siegler; Nikolai A Tsyganenko; Sean C Solomon

doi:10.1126/science.aaa8720

Planetary science. Low-altitude magnetic field measurements by MESSENGER reveal Mercury's ancient crustal field

Science. 2015 May 22;348(6237):892-5. doi: 10.1126/science.aaa8720. Epub 2015 May 7.

Authors

Catherine L Johnson¹, Roger J Phillips², Michael E Purucker³, Brian J Anderson⁴, Paul K Byrne⁵, Brett W Denevi⁴, Joshua M Feinberg⁶, Steven A Hauck 2nd⁷, James W Head 3rd⁸, Haje Korth⁴, Peter B James⁹, Erwan Mazarico³, Gregory A Neumann³, Lydia C Philpott¹⁰, Matthew A Siegler¹¹, Nikolai A Tsyganenko¹², Sean C Solomon¹³

Affiliations

¹ Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada. Planetary Science Institute, Tucson, AZ 85719, USA. cjohnson@eos.ubc.ca.
² Planetary Science Directorate, Southwest Research Institute, Boulder, CO 80302, USA.
³ NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
⁴ The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
⁵ Lunar and Planetary Institute, Houston, TX 77058, USA. Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA.
⁶ Institute for Rock Magnetism, Department of Earth Sciences, University of Minnesota, Minneapolis, MN, 55455, USA.
⁷ Department of Earth, Environmental, and Planetary Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
⁸ Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA.
⁹ Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA.
¹⁰ Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
¹¹ Planetary Science Institute, Tucson, AZ 85719, USA. Department of Earth Sciences, Southern Methodist University, Dallas, TX 75205, USA.
¹² Institute and Faculty of Physics, Saint Petersburg State University, Saint Petersburg, Russia.
¹³ Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA. Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA.

PMID: 25953822
DOI: 10.1126/science.aaa8720

Abstract

Magnetized rocks can record the history of the magnetic field of a planet, a key constraint for understanding its evolution. From orbital vector magnetic field measurements of Mercury taken by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft at altitudes below 150 kilometers, we have detected remanent magnetization in Mercury's crust. We infer a lower bound on the average age of magnetization of 3.7 to 3.9 billion years. Our findings indicate that a global magnetic field driven by dynamo processes in the fluid outer core operated early in Mercury's history. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust inferred from MESSENGER elemental composition data.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.