If you want to get a sense of what's going on inside of your body, you can -- if you have the money or an extremely generous insurance provider -- get a full body scan, using various devices to get detailed cross-sections of your body, a process known as "tomography." But what if you want to get a sense of what's going on inside the Earth? Well, guess what.

A group of Princeton geoscientists just announced that they have used a technique known as "Finite Frequency Tomography" to take an incredibly detailed peek at the inner workings of our home planet. In particular, they have managed to take the first direct measurements of so-called "mantle plumes," massive spouts of hot material rising from the mantle, a 2,000 mile-thick layer just below the Earth's crust. 32 plumes were identified, including one under Iceland (see image).

This gives us a new tool in understanding how our planet functions.

One novel aspect of this planetary body scan was that it used not positron emission or gravity waves or some other extremely high-tech process, but old-fashioned seismographic measurements. The vibrations from earthquakes serve as the equivalent of sound waves, as used in ultrasound scans. Details of the study can be found at Science Express, although you have to be a subscriber (or AAAS member) to download the article. A PDF of the scan images, however, is currently freely available.