Les Johnson is a Baen science fiction author, popular science writer, and NASA technologist. He is the author of Mission to Methone, and co-author of On to the Asteroid and Back to the Moon with Travis S. Taylor, Rescue Mode with Ben Bova, and numerous general science publications. Stellaris: People of the Stars (Baen, September 2019), an anthology Les co-edited with Robert E. Hampson, is a collection of original fiction and non-fiction essays about what may become of humans as we become an interstellar species. To learn more about Les, please visit his website at www.lesjohnsonauthor.com.
In the context of deep space and deep time, humans are newcomers. Astronomers estimate that the universe is about 13.7 billion years old with humans arriving on the scene in only that last 200,000 years. For perspective, as a species, we've only been around for about 0.001% of the time since the universe began. If the age of the universe were one 24-hour Earth day, then humans would have only been around in the last second. We are a blip. To add another layer of humility, consider the diameter of the known universe: about 93 billion light years. To consider this vastness, we again need to put in context with distances we somewhat understand. The Earth is 93 million miles from the Sun and astronomers call this distance 1 Astronomical Unit (AU). The number of AU's in one light year and the number of inches in one mile are almost the same: 1 light year is ~63,000 AU's and 1 mile contains ~63,000 inches. If we scale 1 AU to be 1 inch, then 1 light year equals 1 mile. This means that Alpha Centauri is "only" about four miles away and the diameter of the universe is then "only" 93 billion miles, each "inch" of which is really 93 million miles! We are again only a blip.
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