With the release of Google Earth 5 in February 2009, this freely downloadable virtual globe application gained a feature that makes it much more adept at exploring the oceans: The oceans are now rendered in 3D, using the best global bathymetry dataset currently available.

Here's how to get started exploring interesting polar ocean content with Google Earth 5.

If you haven't already, download and install the latest version of Google Earth, available for Mac, Windows and Linux. Go ahead and launch it.

In Google Earth 5, when you look at the globe from afar, the ocean floor is visible; if you zoom in, an opaque sea surface appears. If you zoom past this surface into the ocean, you'll see a 3D underwater landscape, with sea mounts looking just like blue mountains and undersea trenches like blue valleys.

If you want, you can turn off the opaque water surface by unchecking the View > Water Surface menu item:



Google Earth provides a wealth of default content for the oceans, categorized into layers. These can be found in the Layers sidebar, at the bottom left of Google Earth. Open up the Ocean disclosure triangle, and you'll find:



Many of these default layers contain content for the polar oceans. Just check the box next to each layer to make it visible. Here you'll find the paths and updates from various scientific polar expeditions, marine protected areas near the poles, animals living in polar oceans as recorded by the Census of Marine Life, and some of the best footage of polar animals from the BBC's Planet Earth. Make sure to zoom in sufficiently close to make some content appear. There is plenty there to explore, and many of the popups link through to further information on the web:



Of course, Google Earth is not limited to just showing this default ocean layer. There is plenty of polar-relevant content that you can download and add yourself, letting you visualize information as diverse as sea ice extent, aurora activity, ice drift and even the routes of historical polar expeditions such as that of Ernest Shackleton in 1914-16. All these content layers are