News

  1. Climate

    Petrified tree rings tell ancient tale of sun’s behavior

    The 11-year cycle of solar activity may have been around for at least 290 million years, ancient tree rings suggest.

    By Thomas Sumner
  2. Health & Medicine

    Promise and perils of marijuana deserve more scientific scrutiny

    Report outlines medical potential and health dangers of cannabis and its components.

    By Bruce Bower
  3. Chemistry

    New molecular knot is most complex yet

    The knot is woven from 192 atoms of carbon, hydrogen, oxygen and nitrogen and forms a triple braid with eight crossing points.

    By Meghan Rosen
  4. Neuroscience

    How mice use their brain to hunt

    Messages from the brain’s amygdala help mice chase and kill prey.