Black hole app lets you blow up stars

If you have an appetite for cosmic destruction, there’s an app for that.

NOVA Black Holes, a free iPad game developed by the PBS series NOVA, lets you hurl a star at other celestial objects while navigating an increasingly complex minefield of stars, planets and black holes. Each level presents a new target and a fresh landscape of obstacles. And unlike real stars — whose fates are determined by the weight they’re born with — your star grows bigger and brighter as the game progresses until it collapses under its own gravity to form a black hole. That’s the goal.

The game is addictive — there’s something surprisingly satisfying about blowing up a star. As it hooks you, the game sneaks in tidbits about astronomy and physics along the way.

Early levels are easy: Set the angle and speed of your star, then let it fly toward its mark. As the levels progress, so does the difficulty. A nearby black hole threatens to consume your target before your star gets there. The gravity from a passing star grabs your sun and throws it off course (or possibly ushers it in the right direction). You must get the lay of the gravitational landscape and decide how to aim your star. Sometimes the right strategy is not intuitive: It might be best to swing around the backside of a neighboring star and get a gravity assist to send your star on its way.

Interacting with the game is simple (even if some missions are not). To aim, just touch your finger to your star and pull back, much like drawing a bow and arrow. Numbers showing the speed and angle help you refine your aim on the often inevitable next try. A grid shows how gravity warps the space near each star, helping you plot your trajectory.

Underlying the simple, attractive graphics is a simulator that realistically captures the physics of gravity and orbital motion. Success requires thinking through the implications of how all the stars on the field interact and devising creative ways to use gravity to steer your star. Aiming randomly and hoping for the best works, too.