50 Billion Planets

According to scientists working with data collected from the Keppler Space Telescope, the Milky Way galaxy has approximately 50 billion planets, including 500 million in the “habitable zone” around their stars.


Borucki and colleagues figured one of two stars has planets and one of 200 stars has planets in the habitable zone, announcing these ratios Saturday at the American Association for the Advancement of Science annual conference in Washington. And that’s a minimum because these stars can have more than one planet and Kepler has yet to get a long enough glimpse to see planets that are further out from the star, like Earth, Borucki said.

The implications for sci-fi games are obvious. I haven’t checked any of the games I have at home, but I wonder how close some of them come to those ratios in their own world-building systems. 50% chance for a star to have planets, 0.5% chance for a planet in the habitable zone. Grist for the mill of a scifi RPG design…

Written by 

Wargamer and RPG'er since the 1970's, author of Adventures Dark and Deep, Castle of the Mad Archmage, and other things, and proprietor of the Greyhawk Grognard blog.

7 thoughts on “50 Billion Planets

  1. An interesting idea for a contest or community activity.

    Design planets for a sci-fi game. Just a paragraph or three for each, assorded in a giant list.

  2. It's a staggering thing to think about. Even if there was a one in million chance that each of those life-sustaining worlds had sentient life then you have at least 500 in our own galaxy.

  3. Then it becomes a question of how good your FTL/Stargate/Astral Form/other means of interaction is. 500 civilizations evenly distributed throughout the galaxy may as well not exist from each others' POV unless they have at least a reasonable means of communication…

    But yes, unless you get super-conservative with the numbers you plug into the Drake Equation, there're dozens of peoples out there. And that's just the ones that have radio telescopes!

  4. @ Gratuitous Saxon Violence – Not necessarily in space, but unless whoever explores can be engineered to survive the conditions of the planets, including possible lack of solid ground, there'll need to be stations.

    Thoughtful post and comments.

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