If Mars were a perfectly smooth sphere of uniform density, the gravitational pull experienced by an orbiting spacecraft would be exactly the same everywhere on the planet. But like other rocky bodies in the solar system, including Earth, Mars has both a bumpy surface and a lumpy interior. This causes the gravitational pull felt by a spacecraft to change ever so slightly as it circles Mars. For example, the pull will be a bit stronger over a mountain, and a little weaker over a canyon. Using small fluctuations in the orbital data from three NASA spacecraft—Mars Global Surveyor, Mars Odyssey, and the Mars Reconnaissance Orbiter—scientists created a new map of Mars' gravity field. The map is the most detailed to date, and provides a revealing glimpse into the hidden interior of the Red Planet. Watch the video to learn more.