What protects Earth from exploding stars and cosmic rays? The answer is the heliosphere, a large area of space influenced by the Sun that scientists are still learning about. The shape and size of the heliosphere have yet to be defined, and NASA is considering developing a special “interstellar probe” to help scientists gather data and better understand the heliosphere. Sarah Spitzer, a climate and space sciences and engineering research fellow at U-M, evaluates the effectiveness of an interstellar probe for The Conversation.