Galactic Tick Day

To accelerate awareness of our solar system’s intragalactic journey, David Sneider, a 26-year-old software entrepreneur in San Francisco, along with three of his colleagues, founded “Galactic Tick Day.” Today, September 29, marks our most recent completion of a “galactic tick,” or one centi-arcsecond of our solar system’s galactic revolution. Celebrating this, he says, “can be perspective shifting.”

A galactic tick takes place every 633.7 days, or 1.74 years (the next “tick day” will be on June 26, 2018). Although this is the inaugural celebration of the proposed holiday, Sneider says today is the planet’s 235th such tick (since Sneider and Co. decided, reasonably enough, that the first Galactic Tick Day should fall on the moment when we could first look more deeply into space—the day the patent for the first telescope was filed by Hans Lippershey on October 2, 1608.) If you’re counting since Earth formed 4.3 billion years ago, approximately 2.47 billion ticks have elapsed—or 19.1 complete revolutions around the Milky Way.