Geoff Marcy remembers the hair standing up on the back of his neck. Paul Butler remembers being dead tired. The two men had just made history: the first confirmation of a planet orbiting another star.
Astronomers said Thursday they had found a planetary system with three super-Earths orbiting a bright, dwarf star—one of them likely a volcanic world of molten rock.
Since 2010, the best estimate of the age of Earth's magnetic field has been 3.45 billion years. But now a researcher responsible for that finding has new data showing the magnetic field is far older.