Question

What is the milankovitch cycle and how does it correlate to the ice ages?

Answer 1

The Milankovitch Theory is an explanation for why there were/are Ice Ages.

Explanation:

This theory has 3 components:

1) Eccentricity: the orbit of the Earth changes (very slightly, actually) from a more circular path to a more elliptical orbit. This changes the distance between the Earth and the Sun.

(Earth farther away from Sun => things are cooler here.)

2) Obliquity: Earth's axis is tilted, currently about `23.5^o` to the imaginary plane the Earth moves around the Sun on (the Ecliptic).

This second part of the theory says that the tilt changes over long periods of time. When Earth's axis is more tilted, the seasons are more extreme. When there's less tilt, the seasons are more even.

3) Precession: Over long periods of time, the Earth's axis "wobbles" in space, or precesses, tracing out a circle in space. The Earth's axis is currently pointing at the North Star, Polaris, as our pole star, but in 12,000 years or so, Earth's axis will be pointing at Vega as our pole star.

(If you've ever played with an old-fashioned top, sometimes as it spins, its axis traces out a circle.)

Here's a nice picture I found from skepticalscience.com that I think sums it up pretty well.