Google Earth is a stand alone Google application based on a product originally developed by Keyhole, Inc, which Google acquired in 2004. Essentially a globe that sits in one's computer, the technology uses satellite imagery that allows the user to both zoom in to a particular place or pull back for an overhead view. Using GE in conjunction with other Google features such as google maps allows the user more flexibility and interaction to locate and explore virtually any spot in the world.Google Earth Blog: About Google Earth

Google Earth 5.0 was officially unveiled on Monday, February 2, 2009 at the Academy of Sciences in San Francisco, California. On hand to speak about the powerful educational benefits of the latest version were former Vice President and climate change proponent Al Gore and singer Jimmy Buffett. Amongst the new features being discussed were tools that enable the user to view images from Mars, explore the depths of the ocean and witness various regions of the world evolving over time. The idea to include the ocean feature began 3 years ago when a scientist recognized the glaring absence of water in the application. Now users are able to utilize three-dimensional and historical imaging, which allows them to both explore the depths of the ocean while also witnessing the ongoing affects of climate change upon regional areas of extended periods of time. 5.0 also allows the user to create their own narrated stories using the content and images.SF Gate: Google Earth Allows Exploration of Oceans, Mars (February 2, 2009)