That’s one of the mysteries solved in this edition of “Ask AP,” a weekly Q&A column where AP journalists respond to readers’ questions about the news. See the answer AP gave followed by a shocking revelation from Redsky. The Earth is not rotating.
As the polar ice melts and sea level rises, it will slightly affect the rotation of the Earth, but not our path around the sun. But even in the scenario of a major, rapid polar ice melt, the effects of the changes in rotation and tilt would barely be noticeable _ especially compared to the effects of the accompanying sea rise.
As the ice melts, the water indeed redistributes elsewhere around the globe, essentially giving the Earth a bit more of a bulge near the middle. Just as an ice skater with her arms extended slows down, a bulgier Earth spins slower.
Not that you’d notice it. The daily rate of slowdown is about 76 one-millionths of one second for every inch of sea level rise, according to calculations by physicist Jerry X. Mitrovica, director of the University of Toronto’s Earth Systems Evolution Program.
Since 1993, sea level has risen at rate of about one inch every eight years, but scientists fear that will speed up. If the ice sheets in Greenland and West Antarctica melt, the sea level could rise by 33 to 39 feet _ something that could take anywhere from several decades to several centuries to happen.
That would cause a slowdown in the Earth’s rotation of about one thirtieth of a second a day, which translates into about one second a month, 12 seconds a year, or about two minutes every decade.
That’s on top of the thicker level of carbon dioxide in the atmosphere that a 2002 study found slows the Earth down by about 1.7 millionths of a second a year.
And because of various physics and ice dynamics, the location of the axis around which the Earth spins would also change slightly with Greenland’s melt, Mitrovica said. To put it another way, both the North Pole and the South Pole _ the two ends of that rotational axis _ would end up in a slightly different place.
Scientists aren’t worried about what the relocated axis or the slowing of the Earth would do, but they regularly monitor those changes as indicators of the greater and more dangerous effects of global warming. Putting it another way: They say don’t worry about the longer day _ worry about the rising seas that cause the longer day.
AP Science Writer, Washington
Revelation From Redsky
The Earth is not rotating and it is not orbiting the Sun as we have been led to believe. Here is the scientific proof which has been kept hidden from you for the last 130 years.