When Google Earth was introduced in 2005, it showed how fun digital mapping could be, allowing users to zoom over the planet's continents and explore their most spectacular features. However, 70 percent of the planet's surface--the proportion that is covered by ocean--has always remained off limits to Google Earth users.

In an announcement today at the California Academy of Sciences, in San Francisco, Google has rectified the situation. The latest version of the company's mapping software, Google Earth 5.0, lets users dive deep below the surface of the sea to view ocean-floor topography. Furthermore, they can click on icons that describe aquatic ecosystems and watch, for example, videos of killer whales eating seals. "We have extended the map of the world to include the ocean parts of the world, as well as the land parts," said John Henke, Google lead for the project, in today's announcement.

Sylvia Earle, a renowned oceanographer and former chief scientist at the National Oceanic and Atmospheric Administration (NOAA), played an integral role in adding ocean data to Google Earth. She and Henke met at an event in 2006 where she raved about Google Earth but noted that it should really be called "Google Dirt" because it ignored the part of the planet covered by water. Since then, the pair has worked to add ocean data to the platform.

At today's event, Earle demonstrated a number of new Google Earth features. A user can, for instance, view the migration patterns of the great white shark and see the sort of underwater terrain that the shark sees on its long journey. Earle also showed how the different ocean surface temperatures can be tracked. "You can track the importance of temperature in how El Niño and La Niña form," she said today.

The ocean data added to Google Earth includes more than 50,000 separate measurements, such as the elevation of underwater terrain and more than 20,000 extra pieces of information, including videos, pictures, and text excerpts, said Henke. This information can be added to the virtual map using a taskbar in the software.

Eric Schmidt, Google's CEO, says that the software is more than just a fun visual demonstration. With all the information that it provides, "it's a platform for science and research," he says, "and literally understanding the future of the earth."