Earth Sciences and Ecology Question #2464

Lori Anne Stanger, a 35 year old female from New Liskeard, Ontario asks on January 3, 2005,

As everyone had heard in the news, as a result of the Indian Ocean earthquake and Tsunami of Dec 26, 2004, the earth's spin axis has changed 2.5 cm making for one second shorter days. What effects will this have on earth's weather? In additon, if there are similar incidents...How much can the axis change before it is dangerous to earth (pole shifting etc).

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The answer

Barry Shell answered on January 3, 2005

There are two things going on here. First, you've got your facts wrong. Second, they are not facts, just speculations. The actual change reported was not 1 second, but 3 millionths of a second. Even if we were to worry about a one second change in the Earth's rotation, at the rate of one Richter scale 9 earthquake every 40 years, it would take about 13 million years before the earth accumulated enough shifts to have a change of 1 second out of about 24 hours. Not much. To put this in perspective all recorded human history only goes back 5000 years. There are a lot of 5000s in 13 million. We have time for civilization as we know it to rise and fall, for the human race to die out and be reborn a few times, before you need to worry about this. Note that the Reuters wire release on this (no longer online) says the physicist is "theorizing" this change in rotation. It has not yet been measured, hence it is not real. This is as real as, say, extraterretrial life at the moment. In science, it's important to learn to differentiate between facts and speculations. This is not a fact, but a speculation, an informed but unconfirmed idea. For it to become a fact, a measurement needs to be made. The physicist in the article also says the Earth's poles travel a circular path that normally varies by about 33 feet, so an added wobble of an inch (2.5cm) is unlikely to cause long-term effects. Most of the article in fact is concerned with saying there would be little or no effects.

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