Tag Archives: ice ages

Easy Science: Milankovitch cycles and climate

Milankovitch cycles essentially describe earth's relationship with the sun based on eccentricity, obliquity, and precession. Each of these three components operates on a different timescale, but when they overlap in just the right way, they can reduce insolation (the sunlight hitting the earth) and lower temperatures; conversely, when they work to increase insolation, temperatures go up. For more information on how these cycles influence climate, visit NASA, Skeptical Science, or Wikipedia. Read more

Glacial landforms

Hundreds or even a thousand meters deep and continents wide, the scale and majesty of glaciers is difficult to comprehend. They command 10% of the world's land area and 70% of its freshwater. Their birth and death alter global sea levels to the tens or hundreds of meters. The ice within them always flows, behaving as a ductile solid below 60 meters; above this, the brittle ice cracks into crevasses up to 10 meters wide. When glaciers advance, they grind landscapes, leaving behind unmistakable calling cards in the form of carved mountains, valleys, and lakes. A few of these landforms are discussed below.

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Did a starburst cause Earth to get buried in kilometers of snow?

Three times before the Cambrian period (545 mya), the entire earth has been buried in several kilometers of snow -- based on evidence including tropical glacial deposits and the cessation of carbonate production (which prefers to form in warmer waters) -- in a phenomenon known as Snowball Earth. But what causes these drastic glaciations to occur? Read more