Effects on Habitability from Nearby Neighboring Planets

Kepler-36 c would look as big in the sky from Kepler-36 b as Neptune appears over London in this picture.

This is an excerpt from my post on Astrobites:

Title: Dynamical considerations for life in multihabitable planetary systems
Authors: Jason H. Steffen and Gongjie Li
First Author’s Institution: University of Nevada, Las Vegas, Department of Physics and Astronomy
Status: Accepted to ApJ

We would all like to have good relations with our neighbors, but just how friendly are planetary neighbors?  Could they make your life a disaster, or could they be your best friends?  The authors of this paper explore two aspects of this neighborly relationship:  1) can a planet’s neighbor cause it to tip over more easily, which would cause violent climate change, and 2) can it seed its neighbor with life?