Our sun is one star among 50 billion in the galaxy. Our galaxy is only one among 50 billion in the universe. With a vastness this incomprehensible, it is easy to feel like we are mere specks of sand on an endless shore. But our sun is special. Though roughly 150 million kilometers separate us, we could not be more connected. Literally, everything you see comes from the sun. The words you are reading now are really photons that left the sun about 8...