Ever wonder how the heart symbol came to stand for the actual heart? And why do we speak of the heart as the seat of love, when love really happens in our brains? Is it true that animals only get a billion heartbeats? This week, we give you enough cool cardiac science to make your heart skip a beat.
We are all at the mercy of the Sun. Its glowing disc sustains nearly all life on Earth. But the Sun also holds a dark secret: someday, our aging, expanding star will bathe the Earth in a fiery holocaust. Everything we know will turn to hot, bubbling, plasma.