A team led by Lauren Weiss at the University of Montreal in Canada has looked at 909 planets discovered by the Kepler space telescope in 355 systems. All planets in a given system seem to be close in size and similarly spaced in their orbits when compared with planets in other systems. “We see this pattern happening again and again,” says Weiss – regardless of what kind of star these planets are orbiting (arxiv.org/abs/1706.06204).
Perhaps the types of planetary systems that we are finding are limited by the methods being used to search for them. That is, they all fit a pattern because that pattern is the type of system that we can find with current methods. As new methods develop, we may start finding systems that no longer fit that pattern, or that fit other patterns.
