08-29-2014, 04:09 PM
(This post was last modified: 08-29-2014, 04:15 PM by stevebowers.)
We are near the centre of the Local Bubble, which must have been expanding for millions of years - and which still seems to be actively generating particles. However I don't think the Sun was quite so close to the supernovae concerned when they exploded; we are moving over time, as a speed that exceeds the Local Standard of Rest. In 10 million years we will have moved 550 light years, enough to move us into the bubble from well outside.