Here's another good reason to get out into space, as quickly as possible, and as robustly as possible--we may be past our "extinct by" date.

[Via Alan Boyle]

I wonder what the statistical variance is for that 62 million year number?

Perhaps it could be tied into the precision wobble of the Earth's Axis. We've already seen a slight shift in or polar alignment after the recent tsunami event. Perhaps that is the first of many massive earthquakes to single the Earth settling into a new position.

Or, maybe this could be linked to the Sun's 11 year cycle. It takes several million years for particles in the middle of the Sun's core to wonder their way out to the surface. Perhaps there could be an accumulation of particle fighting for release over millions of years but are otherwise trapped my powerful magnetic forces in a deep boundry layer of the sun. Then, eventually these particle accumulate enough energy to all at once win out over the suns gravity and release a sudden surge of gas and particles that 8 minutes later strip off the upper regions of our atmosphere that protect us from UV radiation. Maybe the extinction cycle is 66 million years.

the precision wobble of the Earth's Axis

If I were an engineer I'd probably be having a great time suggesting definitions for a "precision wobble." ;-)

FWIW, the only reason I know it's "procession" is because when I was a little kid I had a series of books I'd occasionally bring out and read through that dealt with things like that -- pop astronomy, pop geology, pop paleology, that kind of stuff.

Anyway, the statistical variance question is a good one, but I think procession is such a gradual thing I'd be surprised if it was involved. It is believed, however, that the earth's axis shifts seemingly spontaneously every so often. Can't recall if there was a pattern to it or if it's thought to be more or less random.

This would be different from the magnetosphere shifting, which is another thing they think happens every now and then...

Hmmm, McGehee that's pretty good speculation. I was going to suggest that aliens fix up the place every quarter galactic cycle, but unfortunately my Occam's Razor appears to be working. How do I fix that?

Woops, I wrote that while I was procrastinating on getting together my action items for a morning meeting. I was thinking of several things at once compounded by the fact that I had a severe lack of caffeine in my system. Although, I have to correct you right back because I meant to say precession.

pre·ces·sion ( P ) Pronunciation Key (pr-sshn)
n.

1. The act or state of preceding; precedence.
2. Physics. The motion of the axis of a spinning body, such as the wobble of a spinning top, when there is an external force acting on the axis.
3. Astronomy.
1. Precession of the equinoxes.
2. A slow gyration of the earth's axis around the pole of the ecliptic, caused mainly by the gravitational pull of the sun, moon, and other planets on the earth's equatorial bulge.

Although, I have to correct you right back because I meant to say precession.

<smacks self with yardstick>

Ow!

Thank you, may I have another? ;-)

Hmmm, McGehee that's pretty good speculation.

Which one?

I guess we better get on with causing a mass extinction then. We're overdue.

Hrmmm, McGehee, I count just one unit of speculation - the sudden shift in Earth's axis.

My friend is a save the earth,grown green,vote Kuchenich(help me I could never spell his name;),solar power, earth firster. For years I have thrown out the fact that mass extinctions have wiped out most of the species that have ever lived on this planet. That our only recourse is dam the torpedoes full speeeeed ahead, burn all the oil it takes to get us off this incredibly dangerous rock. Now I can torture him with this…thanks