More than 500 million people have downloaded Google Earth since it was launched in 2005. The software is available for free on Google's Web site. Researchers and organizations can purchase a more powerful version for $400.
John Hanke, director of Google Earth and Maps, said the idea of adding oceans came three years ago when a scientist pointed out that the software was missing the water that covers almost three-quarters of the Earth's surface.
Google Earth users can now plunge beneath the ocean's surface, explore three-dimensional images of the underwater terrain and view articles and videos about marine science contributed by scientists and organizations around the world.
The Historical Imagery feature lets users see archive satellite images of individual locations to see how the region has evolved over time as a result of climate change and other forces. For example, viewers can observe how the largest glacier in Glacier National Park has melted over the past decade.
With Google Mars 3D, users can view three-dimensional, satellite imagery of the Red Planet taken during NASA space expeditions.
The new version also allows users to created narrated tours of places using the software's content and images.
"It's not just a fun demo," said Google CEO Eric Schmidt. "What it really is a platform for science and research and literally understanding the future of the world."