MESSENGER Finds Evidence of Ancient Magnetic Field before plunging into the surface of Mercury

In an astonishing paper published today in Science, Catherine Johnson and colleagues show that Mercury's magnetic field, generated by a dynamo process in its molten iron outer core, has been in place for at least 4 billion years. Low altitude observations made by NASA's MESSENGER spacecraft revealed evidence of magnetization of ancient crustal rocks on Mercury and record a magnetic field that could also have been much stronger than it is today and potentially older than Earth's field.The MESSENGER spacecraft crashed onto Mercury's last week after running out of fuel at the end of a 10 year mission. See the UBC-Press articale, the Science link, and a background Science perspective.