How many planets would fit into a Milky Way galaxy? This is certainly not a classic philosophical question like, “How many angels would fit on the head of a pin?” Yet, this question does have philosophical implications if you consider why planet hunters hunt planets. Some, certainly search for planets in our known galaxy because planets are there and we want to learn more about them; but, many who search for exoplanets (planets outside our solar system), do so because they are interested in the possibility of life on other planets; intelligent or otherwise.
The Keplar Space Telescope has recently catalogued 1284 more planets, bringing the total number of discovered planets to 2325. The size of these planets ranges from sub-Mercury to super-Jupiter in size. Some are rocky, some are gaseous, and some just might be habitable. Bob McDonald in a CBC News blog suggests that there are likely more planets in our galaxy than there are stars. Take a look at the night sky and think upon that for a few moments. There may be as many as 10,000,000,000 planets in our galaxy alone. There are more than 100 billion galaxies in the known universe. As we consider only the planets in our galaxy we soon realize that they are too distant by today’s transportation methods for us to visit them with anything more than a telescope, but they are still of interest. Could any of these planets have indigenous life? Would life there be water and carbon-based? Would it be DNA based? Or might it be so foreign in its composition that we would struggle to recognize it as life? Might it exist in liquid water, on dry land, or in the gaseous atmosphere of one of these exoplanets? Would we see signs of communication among creatures of common ancestry? Might we see foliage changes as seasons progressed? What could we look for as signs of life; or signs of intelligent life? Philosophically, the number of planets that would fit into a smallish galaxy appears to be a worthier question than those regarding pins and angels.
 “Kepler telescope doubles its count of known exoplanets: latest data confirm nine more worlds in ‘habitable’ zone”; Science News, May 10, 2016;
 “Finding habitable planets is one thing, finding life quite another” Bob McDonald, blog at CBC News Technology and Science; 2016-05-13; accessed 2016-05-14.