1: The Milky Way Is Vast The Milky Way is an estimated 100,000 light-years in diameter and contains up to 400 billion stars, including our own sun. In spite of such a huge number of stars, the distance between Earth and even our nearest star system Alpha Centauri is vast, and as Douglas Adams pointed out in The Hitchhiker’s Guide to the Galaxy, “Space is Big—Really Big. You don’t know how mind-bogglingly huge space is..” And, of course, he was absolutely correct. Needless to say, comprehending such astronomically large numbers and sizes isn’t easy. Can you imagine 186,282 miles, for instance? Of course you can’t, and yet light travels that far in a single second. Alpha Centauri is 25.6 trillion miles (4.3 light-years) away – good luck imagining that – and to put things into some kind of perspective, if you were to count at a rate of one per second, it would take about 11 and a half days to reach just one million. 2: Just One Of Many Galaxies The...