• Gwen studies the physical processes that shape the surfaces of the Moon and Mars.

• Bart, G.D., H.J. Melosh. (2010) Distributions of Boulders Ejected from Lunar Craters. Icarus, 209, 337-357, doi: 10.1016/j.icarus.2010.05.023 . 
• Bart, G.D., H.J. Melosh. (2010) Impact Into Lunar Regolith Inhibits High Velocity Ejection of Large Blocks. J. Geophysical Research. 115, E08004, doi: 10.1029/2009JE003441l . 
• Bart, G.D., H.J. Melosh. (2007) Using Lunar Boulders to Distinguish Primary From Distant Secondary Impact Craters. Geophysical Research Letters, 34, L07203, doi: 10.1029/2007GL029306 .
  
• Bart, G.D. (2007) Comparison of Small Lunar Landslides and Martian Gullies. Icarus 187, 417-421, doi: 10.1016/j.icarus.2006.11.004 .
  
• Bart, G. D., E.P. Turtle, W.L. Jaeger, L.P. Keszthelyi, R. Greenberg. (2004) Ridges and Tidal Stress on Io. Icarus, 169, 111-126, doi: 10.1016/j.icarus.2004.01.003 .
  
  
  

I study impact cratering on the Moon and Mars.

• My martian project is designed to understand the difference (if any) in the characteristics of ejecta from primary vs secondary craters. Primary craters are formed by a piece of interplanetary material impacting the surface at high velocities (<10 km/s or so). Secondary craters are formed by ejecta from a large crater that is traveling so fast that when it impacts the surface it also forms an impact crater. This study should have implications for understanding the ages of planetary surfaces as determined by crater counting.
• I also have a lunar project that studies a similar primary vs secondary crater problem.
• Finally, I study the depth of the lunar regolith by analyzing the size distributions of craters with specific morphologies that indicate the regolith depth.
• I also have a couple of pending projects: One is for continuing the regolith depth study; the other is for studying lunar landslide features.