"As scientists have discovered more and more exoplanets, they have found that most observed worlds orbit much closer to their stars than any planet in our solar system orbits the sun..."
I am only a layperson but I wonder if these alien solar systems may contain a lot more planets. The ones observed so far could be detected fairly quickly precisely because of their relatively short revolution periods, hence they must be close to their star. What if there are half a dozen more outer planets around this KOI-500 for example they have just not passed before the star yet? The full system may not be so compact, but it could take many years of observation to detect planets that orbit farther out. Perhaps our solar system also had more planets orbiting close to the sun at one point, but after a billion years or so their orbits decayed and they fell into the sun. Isn't it likely that what we observe in other solar systems is essentially these short lived planets? Let's monitor some good candidate stars for another 10, 20 or 50 years, and perhaps more longer orbit outer planets will show up around them.