The main reason Kepler can only see specific kinds of planets is that you need to see three transits before you confirm it, and that the further out a planet is from it&#x27;s star, the less likely it is that it will ever transit.<p>These two combine to make planets closer to the sun much more likely to be seen. If there was another Sol in a perfect place and at perfect alignment and Kepler had been looking straight at it, by now we would have detected Mercury, Earth, Venus and Mars but nothing else.