Message from discussion Antarctic ice sheets may have changed the planet's heartbeat
Received: by 10.66.88.199 with SMTP id bi7mr645906pab.17.1345786563113;
Thu, 23 Aug 2012 22:36:03 -0700 (PDT)
NNTP-Posting-Date: Fri, 24 Aug 2012 00:36:02 -0500
Date: Fri, 24 Aug 2012 00:36:02 -0500
From: Sam Wormley <sworml...@gmail.com>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:14.0) Gecko/20120713 Thunderbird/14.0
Subject: Antarctic ice sheets may have changed the planet's heartbeat
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
Content-Type: text/plain; charset=windows-1252; format=flowed
Antarctic ice sheets may have changed the planet's heartbeat
> You may have seen them before—the graphs from Antarctic ice cores showing the heartbeat of “ice ages” (or glaciations). If so, you probably noted a cyclical pattern, with each glaciation lasting about 100,000 years before being abruptly interrupted by a relatively brief warm period—the interglacial. Soon, the slow freeze inexorably gripped the planet again. There's a reason for this rhythmic pattern—cycles in Earth’s orbit that subtly alter the sunlight reaching the Earth.
> But the graphs have long contained a couple head-scratching mysteries to climate scientists, though. First, why is the 100,000 year cycle dominant? There are several orbital cycles—some around 20,000 years long, another about 41,000 years long, and then the 100,000 year cycle. By itself, the 100,000 year cycle changes things the least, yet it drives the glacial heartbeat.