More Science 10 Unsolved Mysteries in Chemistry Many of the most profound scientific questions—and some of humanity's most urgent problems—pertain to the science of atoms and molecules By Philip Ball THIS IS A PREVIEW. Buy this digital issue or subscribe to access the full article. Already have an account? Sign In Illustration by Brown Bird Design 1 How Did Life Begin? The moment when the first living beings arose from inanimate matter almost four billion years ago is still shrouded in mystery. How did relatively simple molecules in the primordial broth give rise to more and more complex compounds? And how did some of those compounds begin to process energy and replicate (two of the defining characteristics of life)? At the molecular level, all of those steps are, of course, chemical reactions, which makes the question of how life began one of chemistry. THIS IS A PREVIEW. Buy this digital issue or subscribe to access the full article. Already have an account? Sign In Digital Issue $7.99 Add To Cart Digital Issue + Subscription $39.99 Subscribe ADVERTISEMENT Scientific American is a trademark of Scientific American, Inc., used with permission © 2015 Scientific American, a Division of Nature America, Inc. All Rights Reserved.