Ask Ethan: How Many Planets Did NASA’s Kepler Miss?
It’s discovered thousands. But how many more are out there?
“How vast those Orbs must be, and how inconsiderable this Earth, the Theatre upon which all our mighty Designs, all our Navigations, and all our Wars are transacted, is when compared to them.” -Christiaan Huygens
How many planets are there in our galaxy? It’s a question that, 30 years ago, was pure speculation, as we had not yet even found the first planet beyond our own Solar System. Fast forward to the present day, and we’ve directly found thousands of them, with the overwhelming majority discovered by NASA’s Kepler mission. But despite Kepler’s successes and all these new discoveries, what’s more remarkable is all the planets it missed. How many is that? Rudy Siegel (no relation) wants to know:
Since Kepler uses the transit method to detect exoplanets, how many are we missing due to non-ecliptic alignment?
The answer has two parts: we’re missing over 99% of them, and many (maybe even most) of the ones we’re missing have nothing to do with alignment at all.
