Stabilizing the EarthBut to tell you the truth, I really don't understand how the Moon somehow grabs the Earth's axis and holds it relatively steady at a tilt of 23 degrees. Or how without it, the Sun and Jupiter would grab it and yank us around like a dog with a bone. I mean, it's just this imaginary thing after all, right? You can't grab it. You can't push it. You can't pull it.The orientation of the Earth's rotation axis causes the annual seasonal variations of our climate, and small variations in its orientation contribute to the advance and retreat of the ice ages. The obliquity of the Earth, the angle that its spin axis makes with the perpendicular to its orbital plane, is now a modest 23.5 degrees, but this is sufficient to bring summer and winter as the northern or southern hemisphere is tilted toward or away from the Sun. Variation in the Earth's obliquity as small as ± 1.3 degrees, around a mean value of 23.3 degrees, may contribute to, or trigger, the ice ages.
Fig. 5.30. The climate forecast for a Moon-less Earth would be a lot bleaker. The gravitational pull of our large Moon acts as an anchor, limiting excursions in the Earth's rotation axis and keeping the climate relatively stable (Fig. 5.30). Without the Moon, the tilt of Earth's spin axis would vary chaotically between 0 and 85 degrees. Such large variations in the planet's obliquity would result in dramatic changes in climate. With an obliquity of 0 degrees, there would be no seasonal variation in the distribution of sunlight on Earth. At 85 degrees, the Earth's axis would be tipped completely over. The equatorial tropics could then be permanently in cold winter snows, and the poles would be alternately pointed almost directly at or away from the Sun over the course of a single year. Such wide climate changes might be hostile to many forms of life on Earth.
Hey, I could be wrong.
I wonder what mechanism would cause it just to "wobble" and stuff like the Tufts website says?
The earth's pretty hefty, after all. To move it around would require quite a bit of torque!
Without the Moon, the tilt of Earth's spin axis would vary chaotically between 0 and 85 degrees.Really... I thought pole shift would never, ever work because the Earth is an oblate spheroid.