The Shape of the Earth
Bad Astronomy Download time: Apr 21 2011 7:57 AM ET
Last month, scientists using the GOCE spacecraft released a model of the Earth's geoid: essentially, a shape telling you which way is down. If the Earth were a perfectly smooth sphere of constant density throughout, gravity would pull you straight down to the center (perpendicular to the surface). But if a dense hill were nearby, the gravity of that hill would change the direction of the force of gravity. The geoid maps that, and is very useful to understand things like ocean currents and such.
The resulting geoid resembles a bizarre, lumpy Earth. It was pretty neat, but now Nathanial Burton-Bradford has made it better: he took the data and made 3D anaglyphs!…
See Bad Astronomy for links to further info.