"Major punctuation" in 2012 :o
Rampino, M.R., and B.M. Haggerty 1996. The "Shiva Hypothesis":
Impacts, mass extinctions, and the galaxy. Earth, Moon, and Planets
72, 441-460.
“The mass extinction record shows evidence for a periodic component of
about 26 to 30 Myr, and an ~30 Myr periodic component has been
detected in impact craters by some workers, with recent pulses of
impacts in the last 2-3 million years, and at ~35, 65, and 95 million
years ago. A cyclical astronomical pacemaker for such pulses of
impacts may involve the motions of the Earth through the Milky Way
Galaxy. As the Solar System revolves around the galactic center, it
also oscillates up and down through the plane of the disk-shaped
galaxy with a half-cycle ~30±3 Myr. This cycle should lead to
quasi-periodic encounters with interstellar clouds, and periodic
rotations in the galactic tidal force with maxima at times of plane
crossing. This "galactic carousel" effect may provide a viable
perturber of the Oort Cloud comets, producing showers of comets in the
inner Solar System. These impact pulses, along with stochastic
impactors, may represent the major punctuations in earth history.
excuse me?
One of the great things about living here in Atl, is that we are pretty much going to come out on top if various domesday scenarios hit:
Global Warming - If it raises the sea level a lot, our drive to the beach is just that much shorter. If is results in a meltdown of the Greenland ice cap, destroying the convection currents there will be a mini-ice age, making most of the northern US a permanent ice sailing spot (or worse.) The midewest becomes a giant dustbowl. WERE STILL STANDING.
Earthquakes - more likely to push the west coast into the ocean. Ruining the Gorge, but no impact on us.
Volcanos - mud slides from Mt. Ranier and Mt. St. Helens cover Seattle and Portland, and may fill in low spots, like the Gorge but WERE STILL STANDING.
VOLCANOS - Wyoming (Yellowstone) Caldera goes off. Covers most of the US in ash, many feet deep, but we probably hold out as long as anyone.
Comet/Asteroid strikes - a direct hit is no more likely here than anywhere else, but a ocean strike (with Tsunami) is more likely (70/30 odds). Were 1000 feet above sea level. WERE STILL STANDING. AND SAILING!
Tsunami - see above.
Nuclear War - as best I know, we have no ICBM targets in GA. So were not likely to be the first strike target.
Armagedon - well, this is the Bible Belt. Were probably not the first place that would be hit.
So there you have. Sure, were still at risk, like everyone else for super novas, the moon colliding with the earth, earths gravity suddenly being shut down, invasions of locusts. Our biggest theat may be killer bees. So we can't necessarily breath a total sigh of relief, but I like our odds.
What happens in a black hole stays in a black hole.