In this series about an ancient crater, its cause and the man who figured out its origins, Tennant shows her knack for enlivening science, for imbuing scientific questions with mystery and portent. Her lead has no human character, but it tantalizes with vivid action and a wealth of stunning detail. (It seems that crafting a compelling description of a two-mile-wide object hurtling toward earth should be easy; but not necessarily.) Tennant’s protagonist is a compelling character on a quest. Even without him, Tennant could keep readers intrigued through the strength of her voice and the suspense she builds in pursuit of an intellectual mystery.