clipped from: science.nasa.gov   
NASA - National Aeronautics and Space Administration Science@NASA Web Site

4D Ionosphere

April 30, 2008: Today, NASA-funded researchers released to the general public a new "4D" live model of Earth's ionosphere. Without leaving home, anyone can fly through the layer of ionized gas that encircles Earth at the edge of space itself. All that's required is a connection to the Internet.
clipped from: science.nasa.gov   
How to Launch the 4D Ionosphere

"One, download and install Google Earth."

"Two, visit our web site and click on the link 'Total Electron Content.'"

Wait for the file to load and presto—you're flying through the ionosphere. A typical screenshot looks like this: