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Scaling in Comparative Planetary Sciences: Dust Lifting on Earth, Mars and Beyond

Scaling in Comparative Planetary Sciences: Dust Lifting on Earth, Mars and Beyond. Nilton O. Renno and Jasper F. Kok University of Michigan Ann Arbor, MI. Outline. Good Times at MIT Peter’s welcome Pranks Electrostatic and Dust Lifting Dust devils and dust storms Laboratory experiments

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Scaling in Comparative Planetary Sciences: Dust Lifting on Earth, Mars and Beyond

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  1. Scaling in Comparative Planetary Sciences: Dust Lifting on Earth, Mars and Beyond Nilton O. Renno and Jasper F. Kok University of Michigan Ann Arbor, MI

  2. Outline • Good Times at MIT • Peter’s welcome • Pranks • Electrostatic and Dust Lifting • Dust devils and dust storms • Laboratory experiments • Moon, asteroids, etc • Saltation and Climate • Background • Our new model • Results • Effects of Dust Electrification • Electric discharges on Mars • Effects on atmospheric chemistry • Our New Electric Field Sensor • Conclusions Peter H. Stone Symposium, MIT

  3. How is this related to Peter’s mentorship? • Use scaling laws to gain insight on the basic physics • Use a hierarchy of models to get a deeper understanding of the problem Peter H. Stone Symposium, MIT

  4. Good Times at MIT Peter H. Stone Symposium, MIT

  5. Peter’s welcome • “Your English is good enough.” I believe that you will survive… (Thank you, Arlindo!) • I quickly learned what Peter meant by “you will survive.” Everything was much more intense than I imagined, but also new and exciting. I loved it! Peter H. Stone Symposium, MIT

  6. Pranks • My first article with Peter (and Kerry) • Last sentence of my letter to the JGR editor: “No peer review necessary, please accept immediately.” • A few months later… Peter strikes back with a much better prank! Peter H. Stone Symposium, MIT

  7. Electrostatic and Dust Lifting Peter H. Stone Symposium, MIT

  8. Electric Fields in Terrestrial Dust Devils (~ 1 m above ground) (Farrell et al. 2004, Renno et al. 2004) Peter H. Stone Symposium, MIT

  9. Terrestrial Dust Devils Ubiquitous in arid regionsfrom spring to fall Peter H. Stone Symposium, MIT

  10. Electric Fields Close to the Surface During Saltation (Schmidt et al. 1998) Peter H. Stone Symposium, MIT

  11. Martian Dust Devils & Storms Relatively rare Ubiquitous Credit: NASA/JPL/MSS (Both Images) Peter H. Stone Symposium, MIT

  12. 2007 Mars Dust Storm Peter H. Stone Symposium, MIT

  13. Dust Lifting by E-Fields (Kok and Renno 2006) Peter H. Stone Symposium, MIT

  14. (Kok and Renno 2006) Peter H. Stone Symposium, MIT

  15. Threshold E-Field for Dust Lifting F = d (Shao and Lu 2000) (Kok and Renno 2006) Peter H. Stone Symposium, MIT

  16. Charge Distribution in Dusty Plumes and Vortices • - - - - - - - • - - - • - - • - - - • - - • - - - • + + + + Peter H. Stone Symposium, MIT

  17. Electrostatic Cleaning on MER? Images taken on Sol 416 (March 5) and Sol 426 (March 15) respectively.Credit: NASA/JPL/Cornell Peter H. Stone Symposium, MIT

  18. The Surveyor (S-1 to S-7) Missions Right: Surveyor III & Apollo XII Peter H. Stone Symposium, MIT

  19. Lunar Horizon Glow (HG) wasObserved by S-1, S-5, S-6, S-7 (Criswell 1973) Peter H. Stone Symposium, MIT

  20. Composite of Five Surveyor 7 Images (Rennilson and Criswell 1974) • The HG can explained by forward scattering from • ~ 50 particles/cm2 of d ~ 10 m • This is 107 more particles than ejected by micrometeorites Peter H. Stone Symposium, MIT

  21. Crepuscular Rays on the Moon? Terrestrial crepuscular rays The Lunohod-2 astrophotometer showed that the “twilight” lunar sky is 20 times brighter at visible wavelengths than expected from star light (Severny 1975) (McCoy 1973) Peter H. Stone Symposium, MIT

  22. Lunar Eject And Meteorite (LEAM) Experiment • Most detection were near the terminator • Caused by impacts of charged dust particles with velocities up to 1 km/s • Hypervelocity impacts from micrometeorites were rare (Berg 1976) Peter H. Stone Symposium, MIT

  23. Predictions for the Moon (Kok and Renno 2007) • This suggests • that cohesion is • 3 orders • of magnitude weaker on the • lunar regolith • than on terrestrial soils Peter H. Stone Symposium, MIT

  24. Our Predictions for the Moon • Electric fields of about 25 kV/m are necessary to levitate lunar dust particles with diameters d ~10 mm • Soft solar X-rays remove electrons with energies of 500-1500 eV and can produce cm-scale fields of more than 100 kV/m • The smaller dust particles “observed by Apollo” astronauts at 1-100 km above the lunar surface: • Solid particles of ~0.01 mmcan easily reach a few km • Lower density agglomerates can reach higher altitudes Peter H. Stone Symposium, MIT

  25. Ponded Deposits on Asteroid Eros (Robinson et al. 2001) NEAR-Shoemaker Mission Peter H. Stone Symposium, MIT

  26. Dust Lifting on Asteroids  = Fc/d Peter H. Stone Symposium, MIT

  27. Peter H. Stone Symposium, MIT

  28. Electrostatic Dust Lifting? JPL/NASA U. Chicago Peter H. Stone Symposium, MIT

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