Tapping on any planet will take you close to it, and you can use your finger to orbit the planet and see it from any angle or zoom. You can see the planets on any particular date and time, and speed up the animation to watch the planets in their elliptical orbits.
Tapping the info button gets you some information on all the planets, like size, gravity, composition and more. One omission is that the program doesn't tell you which planets are up for viewing on a particular night. You'll need Star Walk for that.
The smooth finger controls combined with the spectacular graphics make this a perfect demo for the iPad. Dragging your finger to fly around the planets is a bit intoxicating, and I'm impressed with the smooth animation.
Complaints? I do have a couple. As mentioned, the app should tell the user what planets are visible in the night sky. I found the textual information thin. Just playing with the app will raise a lot of questions about the planets and the way the solar system works -- I wanted to read more, and I expect many users will agree. I hope the developers will put a lot more info into this program. Some old timers will be mad that Pluto isn't part of the program, but of course Pluto lost planet status in 2006, and is now classified as a 'dwarf' planet.
Future versions of Solar Walk are expected to have 3D views that work with red/blue 3D glasses. Asteroids will be added, as well as the International Space Station.
This is a great app for the space enthusiast. It works great for kids or adults, and I'm looking forward to where this app goes in future updates. As it is now, it's very entertaining and informative, with jaw dropping graphics.
Solar Walk is U.S. $2.99. It works on the iPhone, iPad, and iPod touch, and requires OS 3.1.3.