Lost in migration: Earth's magnetic field overdue a flip

Lost in migration: Earth's magnetic field overdue a flip | Reuters: "(Reuters) - The discovery by NASA rover Curiosity of evidence that water once flowed on Mars - the most Earth-like planet in the solar system - should intensify interest in what the future could hold for mankind. The only thing stopping Earth having a lifeless environment like Mars is the magnetic field that shields us from deadly solar radiation and helps some animals migrate, and it may be a lot more fragile and febrile than one might think."