What's the closest planet to our Sun? Mercury! Mercury orbits the Sun very quickly --in fact, it circles the Sun four times more quickly than Earth. With a surface covered in craters, it's also the smallest planet. Early readers will be taken on a journey through outer space as they learn these and other fascinating facts about Mercury. Each 24-page book features controlled text with age-appropriate vocabulary and simple sentence structure. Stunning photos closely align with descriptive text that will grab kids' attention. Emergent readers won't be able to stop turning the pages as they explore Earth's solar system. Get ready to blast off!