New study uses Twitter to look for predictions of the future . Research found no future predictions of Comet ISON or Comet Francis . Or , you know , it might be physically impossible to travel to the past . ` Physicists say space travel is probably not possible .
New study uses Twitter to look for predictions of the future . Research found no future predictions of Comet ISON or Comet Francis . Physicists say space travel is probably not possible .