Google updates Mars on Google ... Earth??

Where's the first place you'd look for maps of Mars?

If you didn't say Google Earth, why not? After all, a 3D mapping tool of Mars was added to Google Earth for the 5.0 release. But Google today announced an update to the program that includes historical maps and images, a stream of the latest images from the Red Planet and not one, but TWO guided tours of the fourth rock from the Sun.

In the Google Earth toolbar, you can select "Mars," and you then swoop in on the planet, with a 3-D view that includes layers and imagery. You can do all sorts of nifty things, just as if you were looking at, say, Earth - zooming in and out, switching camera views or giving the entire planet a nice rotation by clicking on your mouse.

The new "historical maps" layer offers antique maps by Giovanni Schiaparelli and Percival Lowell, among others. The "Live from Mars" layer is a continuous stream of imagery from NASA's camera on the Mars Odyssey spacecraft and the Mars Reconnaissance Orbiter. The two guided tours are narrated by Ira Flatow of Public Radio's Science Friday and Bill Nye (the Science Guy).

There are lots of updates to the original imagery, too, and the search function's been improved, according to Google.

There's a browsable layer of our favorite satellite images, visible and infrared global views, geo-located excerpts from A Traveler's Guide to Mars, and others. We've also included 3D models of NASA rovers and, if you follow their tracks, the 360-degree panoramic photos they captured from the surface. Just like browsing on Earth, you can use the search box to locate famous sites like the face on Mars.

You can get it all by downloading Google Earth here or checking out the features here.