Astronomers solve 900-year-old cosmic mystery surrounding Chinese supernova of 1181AD
Caught in a web: Study reveals that immune cells cooperate to trap and kill bacteria
Earth's magnetic north pole has been shifting south at speeds up to 30 miles per year recently. That's prompting some scientists to suggest we're on the brink of a geomagnetic reversal, where Earth's magnetic north and south poles swap places. Such a reversal hasn't happened for 780,000 years.