Cats in space? Sign me up! Professor Astro Cat's Solar System (Minilab Ltd., December 2015; iOS only), a digital adaptation of Dr. Dominic Walliman and Ben Newman's 2013 nonfiction book Professor Astro Cat's Frontiers of Space, introduces users to our solar system — with plenty of humor and a retro, space-race vibe.

Choose a kitty-cosmonaut (cat-stronaut, if you will) character as an avatar, then follow Professor Astro Cat and assistant Astro Mouse on a guided tour through our solar system. Tap each planet, moon, or space vehicle to explore facts about it and access a cutaway view. Icons at the bottom right bring up a size comparison of the planets (with a helpful visualization of planets as fruits and veggies — did you know Jupiter is a watermelon to Earth's cherry tomato?) and an animated diagram of their orbits. Some information could be communicated more clearly, but overall the app offers users solid facts and fascinating tidbits presented in an accessible way.



Earn medals and collect pieces to build your own rocket by completing ten-question, true-or-false "Jetpack Challenge" quizzes following each section. Once you've finished all of the challenges — getting promoted through the ranks as you do so — and put the finishing touches on your rocket, you blast off to a shower of ticker tape and the sound of cheers. Upbeat music and sound effects add to the app's friendly feel, but can be easily turned on/off.



In her review of the print version, our intern Liza called Professor Astro Cat "a great book to nurture interest in and wonder at the infinite possibilities of space." If anything, this engaging app adaptation only enhances the considerable merits of the print book.

Available for iPad, iPhone, and iPod touch (requires iOS 7.0 or later); $2.99. Recommended for primary and intermediate users.