In this issue:
"The Search for Planet X": In the far reaches of the solar system, a hidden planet larger than Earth may be lurking.
"Bitter Taste Bodyguards": Bitter taste receptors are not only on the tongue but throughout the body, where they defend us against microbial invaders.
"The Quantum Hack": Quantum computers will render today's cryptographic methods obsolete. What happens then?
"Six Billion in Africa": Population projections for the continent are alarming. The solution: empower women.