• News

    Motor design flouts physical law

    A proposed silicon device the size of a red blood cell would transform random thermal motion into useful mechanical power in violation of the second law of thermodynamics, its designers claim.
  • News

    Putting the brakes on antihydrogen

    By mixing ultracold antiprotons and antielectrons, physicists have created the first atoms of antihydrogen that move at a leisurely enough pace for direct measurements of their properties.
  • News

    Brain trait fosters stress disorder

    A brain-scan study of pairs of twin brothers, in each of which only one twin had been a Vietnam combat veteran, indicates that the inheritance of an undersized brain structure called the hippocampus predisposes individuals to post-traumatic stress disorder.
  • News

    Ant cheats plant; plant cheats back

    An Amazonian tree grows little pouches on its leaves to invite ants to move in and provide guard duty, but the tree drops the pouches from old leaves because ants ravage the flowers.
  • News

    Enlarging a Mars photo album

    A new set of more than 18,000 images of Mars, posted online in early October, features the sharpest picture of the Red Planet ever taken by an orbiting spacecraft.
  • Feature

    Once Upon a Lake

    As Earth warmed at the end of the last ice age, the immense volumes of fresh water that occasionally and catastrophically spilled from Lake Agassiz—the long-defunct lake that formed as the ice sheet smothering Canada melted—may have caused global climate change and sudden rises in sea level.
  • Feature

    Election Selection

    By ignoring how voters might rank all the candidates in an election, the plurality system opens the floodgates to unsettling, paradoxical results when there are three or more candidates.