Posted on 04/30/2006 4:35:48 PM PDT by blam
The disposition of the continents would be a factor. Were they all on the equator, there may have been no ice age. Milankovitch worked out the correlations (long before computers) and gave a plausible explanation. It's not clear that the various tilts are enough in themselves to trigger an ice age; however, with a bit more cooling, it could happen. Stochastic® Resonance was invented (or at least invoked) to explain ice ages.
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"Castasrophism"
Yeah, that's easy for you to say, but climatologists call it "grants".
"Castasrophism"I was a little scared for a second, thought I really had spelled it that way...
Yeah, that's easy for you to say, but climatologists call it "grants".
Maybe the ice got too heavy on one side and made it tilt after the fact!
Geologist Joe Kirschvink has combined both continental drift and slipping crust ideas to arrive at the theory that what we know as the continents of the Earth slid around en masse over a period of 15 million years. This took place after the supposed breakup of the alleged Pangea supercontinent, when there were two continental groups. North America was near the south pole, and rest of the landmasses were joined in Gondwanaland and stretched from pole to pole. Kirschvink used remanent magnetism in rock strata to determine that the whole crust turned counterclockwise (in the drawing) and left North America near its current latitude while Antarctica and Australia were jammed together near the equator. [ Earth magazine, June 1998, pp. 34-37 ] 90 million years ago an island in what we call the Arctic enjoyed weather similar to Georgia or Florida, despite not having budged much from its current relationship to the Earth's rotational axis.
The obvious problem with all gradualists "explanations" is obvious -- not all of the Arctic was glaciated, and some of the areas at the same latitude were downright pleasant. Meanwhile, during the summer, the Sun was hotter, meaning that the glaciation would have to accumulate basically in one year, because the summer heat would have been considerable and would have melted everything.The Earth's Changing OrbitIf the earth and the sun were the only bodies in the solar system, the earth's orbit would not change. However, the moon and the other planets are constantly pulling on the earth. The result is that the angle between the earth's axis and the plane of its orbit, the season at which the earth is closest to the sun, and the degree to which the earth's orbit is elongated all vary slowly over time. Right now, the elongation of the orbit (the eccentricity) is rather small -- about 1.7%. This results in the sun being about 7% brighter at the earth when it is closest, on January 4, than when it is most distant.
by Sue Ann Bowling
June 15, 1987
Alaska Science Forum
Twelve thousand years ago, when the glaciers of the last great ice age were melting, the eccentricity was a bit higher, about 2%. At the same time, the earth was closest to the sun in June, and most distant in January, so the sun was about 7 % brighter in June than it is today. At various times in the last million years, however, the eccentricity has been much higher -- as much as 6%, which would make the sun almost 25% brighter at perihelion (when the earth is closest to the sun) than at aphelion (when the earth is farthest from the sun). During the interglacial before the last ice age, about 125,000 years ago, the eccentricity was about 4%. The times of largest eccentricity tend to be about 100,000 years apart.
Not easy to spot, doesn't understand why it happens, but this help explains irregular intervals. Uh-huh, yeah, right.Earth's Changing Orbit Explains Ice Ages[V]ariations in the Earth's orbit around the Sun could explain why ice ages, which occur about every 100,000 years, have not been more regular... Jose Rial, a professor of geophysics at the University of North Carolina at Chapel Hill... looked at isotopes, or variants, of oxygen found by drilling into the sea floor. Such "heavy" oxygen is found more commonly when it is cold. Rial found evidence of both the 100,000 and 413,000 year cycles, but said they were not so easy to spot because the two "interfered" with each other in much the same way that interfering with radio waves -- a process known as modulation -- allows broadcasters to send information in the form of sound. He said the pattern looked like an FM (frequency modulated) radio wave. He does not know the physical mechanism behind this but says it helps explain why the ice ages seemed to occur at irregular intervals.
7.49 a.m. ET (1149 GMT) July 23, 1999
...and call yourself a "scientist."
Yes, that's right, the winds fluctuate pressure on the bottom of the oceans, despite the fact that the mass of the entire atmosphere is the same as the top 35 feet or so of the world's oceans, which are miles deep, and yet are orders of magnitude less massive than the Earth itself.Earth throws a wobblyA mysterious wobble that shakes the Earth as it spins on its axis is caused by pressure changes at the bottom of the ocean, say scientists at Nasa's Jet Propulsion Laboratory... The force of the wobble is such that it is capable of moving the North Pole about six metres (20 feet) from where it should be. The Chandler Wobble period lasts around 433 days, or just 1.2 years... Scientists originally calculated that this phenomenon should naturally run out of steam after 68 years unless some force keeps activating it. And this is precisely what appears to happen. Writing in the 1 August issue of Geophysical Research Letters, NASA's Richard Gross says the principle causes of the wobble are fluctuating pressures on the bottom of the oceans. These fluctuations are the result of changes in temperature, salinity and wind patterns. Using data from International Earth Rotation Service, in Paris, Gross says that two thirds of the wobble can be attributed to these ocean bottom pressure changes and one third to alterations in atmospheric pressure.
Tuesday, 18 July, 2000
Y'know, it just seemed like a good idea to juxtapose.Earth, The Magic TopEmploying a wide span of data from complex top theory to ancient legend, Warlow suggests that the earth has undergone many violent catastrophes, some of them within the time of man. Flood legends, geomagnetic reversals, tektites, paleoclimatology, salinity crises, and other familiar standbys of the catastrophists force P. Warlow to examine the stability of the earth in the presence of astronomical collisions and near-collisions.
William R. Corliss
Science Frontiers ONLINE
No. 6: February 1979
He shows that the earth rotates slowly and that, even with the stabilizing equatorial bulge, our planet is rather sensitive to outside forces. It is, he says, like a tippe top or magic top; a 8,000-mile-diameter top that turns over repeatedly in response to external influences. Did not the ancient Egyptians write that the sun once rose in the west? Are there not massive faunal extinctions? Have not stray solar-system bodies left scars on all the inner planets?
Yes, quite a statement, and based on gross ignorance. The seasons are based on the tropical year, which is defined by the earth's orientation with respect to the sun, and this tropical year is the basis of the calendar year, so the seasons remained fixed on the calendar.
The precession of the equinoxes expresses the difference between the tropical year and the sidereal year. The slightly shorter tropical year means that the stars appear to creep ahead of the sun by about 50.26" of arc each year.
In several thousand years, the familiar "summer constellations" will no longer appear in the same positions in the summer months of July and August, assuming the current conventions and practices survive that long.
How could two Hollywood animated movies be responsible for tilting earth?
Especially movies that are so cute and cuddly.
They're talking astronomy, not meterology, and it's very predictable.
If ice ages are blamed on the earth's tilt, than by definition any global warming can only be traced to the same... which means that short of figuing out a way to change the earth's tilt one way or another, there's not much we can do about it either way!!! Which means the liberal moonbats are full of it!!!
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