So long, and thanks for all the fish.

Astrobiologists at the Cardiff Centre have built a model of our solar system travels through our galaxy. Our solar system is on the outer edges of one of the spiral arms of the Milky Way, taking its sweet ole time to complete a complete revolution (around 250 million years, if I remember correctly). But that's not the only movement of the solar system. Apparently, it bounces up and down through the plane of the Milky Way every 35-40 million years -- and with each bounce through the plane, the solar system is exposed to a denser region of the galaxy -- the plane has much more stuff. A bounce through that stuff could lead to catastrophic events -- such as comets colliding with Earth. In fact, the 35-40 million year cycle coincides quite well with mass extinction events on Earth.

Now here's the bad news. We're up for another bounce through the galactic plane -- tomorrow in fact -- so place your head firmly between your knees, it's going to be a rough ride.