New Scientist reports on a new paper from David Smith at the University of Arizona in Tucson and the University of Texas, Austin's John Scalo that declares that the sun's heliosphere protection shrinks as the solar system passes through very dense gas and dust clouds, exposing us to harmful space dust and cosmic rays. Smith notes that planets orbiting red dwarf stars aren't affected by similar shrinkage due to their closeness to the star:
The bottom line is that habitable planets around red dwarfs are better protected from climate catastrophes than Earth is.
Don't feel too under threat, however; according to the paper, Earth is only being exposed to cosmic rays between one and ten times every billion years.
Sun leaves Earth wide open to cosmic rays [New Scientist]