Feature

  1. Math

    Tied Up in Knots

    Physicists have shown that tumbled strings will form surprisingly complex knots, helping explain how knots spontaneously form in nature.

    By Davide Castelvecchi
  2. Earth

    Dead Serious

    Little progress has been made this decade in reducing the size of the Gulf of Mexico's dead zone, a massive area of oxygen-depleted water caused by agricultural and urban runoff.

    By Sarah Williams
  3. Earth

    North by Northwest

    The Earth's magnetic poles wander around quite a bit, a phenomenon that occasionally confounded ancient explorers but is proving useful for today's archaeologists.

    By Sid Perkins
  4. Health & Medicine

    The Long Road to Beta Cells

    In their quest to cure type 1 diabetes, scientists are finding that turning stem cells into insulin-producing beta cells is a lot harder than it first appeared.