Scientific American, July 2015

In this issue:

"Mystery of the Hidden Cosmos": The invisible dark matter particles that dominate the universe may come in strange and varied forms.

"What Doesn't Kill You…": Chemicals that plants make to ward off pests stimulate nerve cells in ways that may protect the brain against diseases such as Alzheimer's and Parkinson's.

"Life at Hell's Gate": An astonishing discovery is forcing scientists to reconsider whether life can exist in the most extreme places on Earth and in space.

"Out-Shining Silicon": An upstart material – perovskite – could finally make solar cells that are cheaper and more efficient than the prevailing silicon technology.