Posted on 05/20/2010 7:21:00 PM PDT by SunkenCiv
:’) It’s plausible enough, assuming the aliens came from a planet that was covered by volcanoes. ;’)
I loved those great old spooneristic punchlines.
“Wait ‘til the nun signs, Shelly.”
“Silly rabbi! Kicks are for Trids.”
“Let your pages do the walking through the yellow fingers.”
“If the Foo sh!ts, wear it.”
I was thinking if those really were footprints made in Mexico a million years ago, who knows?
• ” (me)Everything that I have read says that magnetic reversals and pole shifts are real” (You)Then why are they only found near volcanic action, and tektonic joints?
(me) Because of the iron(you)Because of the turning of fragments of crust.
(you)Lava is insignificant to the subject, since iron heated to near melting point loses most or all of its magnetism, leaving it to regain a new field over time.
First you say they are only found around volcano's then for the reason for the different directions you say the turning or churning of the crust and then you finally say that Lava is a insignificant to the subject.
So what's it going to be?
From what I have read it is from the core samples taken from around volcano's that they find the iron in the lava has aligned up in different directions due to the magnetic alignment of the poles at the time of the lava flows.
Yeah, it wouldn’t be too surprising, at all.
“So what’s it going to be?”
.
When a volcano erupts, often large chunks of solidified rock are thrown huge distances, and end up tumbling on the surface when they land. They subsequently get buried in first ash, and later lava. It is the normal course of events in a large eruption.
The magnetic alignments of those chunks never match the surroundings.
.
>”From what I have read it is from the core samples taken from around volcano’s that they find the iron in the lava has aligned up in different directions due to the magnetic alignment of the poles at the time of the lava flows.”<
.
The findings are correct, but the reasoning is absurd.
OK?
When the volcano erupts it will have lava flows and if the volcano erupts several time through out it life and if the poles have shifted it will be recorded in the lava.
What is absurd about that?
What is absurd is that the poles have never shifted, and the whole idea of magnetic pole shift lacks any basis in geophysics.
Nobody has ever been able to provide a means or force by which such a shift could really happen. Without a means, there is no event. Its an answer to a question that hasn’t been asked.
What caused the suns poles to flip last year?
February 15, 2001 -- You can't tell by looking, but scientists say the Sun has just undergone an important change. Our star's magnetic field has flipped. The Sun's magnetic north pole, which was in the northern hemisphere just a few months ago, now points south. It's a topsy-turvy situation, but not an unexpected one. "This always happens around the time of solar maximum," says David Hathaway, a solar physicist at the Marshall Space Flight Center. "The magnetic poles exchange places at the peak of the sunspot cycle. In fact, it's a good indication that Solar Max is really here."
So what has affected the sun to the point of the poles fliping?
The sun is a gaseous body, with a complex magnetic field that branches in a cyclic pattern. That is what is called “sun spots.”
The sun is presently in a low energy state. Some say that it has shut down.
From Nasa
Sometimes the field completely flips. The north and the south poles swap places. Such reversals, recorded in the magnetism of ancient rocks, are unpredictable. They come at irregular intervals averaging about 300,000 years; the last one was 780,000 years ago. Are we overdue for another? No one knows.
A solid core of hydrogen and helium?????
We have departed from the relm of physics.
.
So what's this? You have to find a pigeon hole for E-S so you know where to disagree? Why not just argue the point if you disagree? No need for stereotyping.
When did NASA become ‘reputable?’
NASA has supported much nonsense, like global warming for example. NASA supports anything that will expand their budget, including such specious crap as misusing readings along tektonic zones to assume magnetic pole changes.
Sci-Fi
(PhysOrg.com) -- Based on studies of old volcanic basalt, scientists know that the Earth’s magnetic field reverses at irregular intervals, ranging from tens of thousands to millions of years. Volcanic basalt rock contains magnetite, and when the rock cools, its magnetic properties are frozen, recording the Earth's magnetic field of the time. With this data, scientists estimate that the last magnetic field reversal occurred about 780,000 years ago.
Although volcanic basalt reveals when reversals occurred, it’s much more difficult to find evidence for why or how the Earth’s magnetic field reverses. In a recent study, scientists from the Ecole Normale Supérieure and the Institut de Physique du Globe de Paris, both in Paris, have proposed a general mechanism that provides a simple explanation for field reversals. In their model, small fluctuations in convective flow in Earth’s core can push the planet’s sensitive magnetic system away from one pole toward an intermediate state, where the system becomes attracted to the opposite pole.
“We have found a mechanism that gives simple explanations of many features of the reversals of Earth’s magnetic field,” François Pétrélis of Ecole Normale Supérieure told PhysOrg.com. “In particular, it explains the existence and the shape (slow phase followed by fast phase) of reversals, the existence and the shape of aborted reversals (‘excursions’), the statistical properties of reversals, and the possibility for very long durations without reversals (‘superchrons’).”
At present times, the Earth’s magnetic field can be described as a magnetic dipole, with the magnetic south pole currently located near the Earth’s geographic north pole, and the magnetic north pole near the geographic south pole (both magnetic poles are misaligned along the Earth’s rotational axis by about 11.3 degrees). The existence of such a long-lived magnetic field can be explained by dynamo theory, which describes how a convective, electrically conducting fluid that rotates can maintain a magnetic field.
As the scientists suggest, the reversal mechanism relies on the existence of a second magnetic mode, in addition to the dipolar field. The presence of a second mode, such as a quadrupolar field, can have significant effects on how the magnetic system reacts to changes in equatorial symmetry. As the researchers explain, the equator can be thought of as a plane of symmetry, and the convective flow in the Earth’s outer core is usually north-south symmetric. Previous studies on paleomagnetic data have proposed that reversals involve an interaction between the dipolar and quadrupolar modes, which would correlate with changes in equatorial symmetry. In support of this idea, some recent numerical simulations have shown that reversals do not occur when the convective flow remains equatorially symmetric.
“The quadrupolar field (it is likely to be a quadrupole but another structure could be possible) is also generated by the flow of the liquid core of the Earth, exactly like the dipolar field,” explained the researchers. “Most of the time, we observe a dipolar field because it is more easily generated by the flow, but in other conditions a quadrupolar field could be maintained, and this occurs in a temporary manner during a reversal.”
To further explain the dipole-quadrupole interaction, the scientists invoked a model that was recently used to describe the dynamics of a magnetic field generated in a very different system: a lab experiment involving a von Karman swirling flow of liquid sodium (which, like the Earth’s magnetic field, is generated by the dynamo effect). The scientists suggest that a general mechanism could explain both magnetic fields, independent of the different symmetries and velocities of the two systems.
“We have shown that if the dipolar field of Earth is coupled to another magnetic mode (a quadrupolar field, for instance), this coupling provides a path to flip the dipole to its opposite,” the scientists said. “If this coupling is strong enough, the magnetic field will spontaneously oscillate between the two modes and their opposite polarities. We will then observe periodic reversals of the magnetic field (this is the case of the solar magnetic field, for which the period is 22 years). In the case of Earth, the coupling is not strong enough, and oscillations are not observed. Velocity fluctuations in the liquid core are then needed to trigger a reversal.”
In the model, small fluctuations in convective flow can push the system away from one pole toward the intermediate quadrupolar state, where it becomes attracted to the opposite pole. A reversal occurs in two phases: a slow phase where the fluctuations are the motor of the evolution, and a fast phase during which the dynamics does not rely on the fluctuations. The first phase, during which the dipole amplitude decreases slowly, seems to last around 50 kiloyears (30,000-70,000 years). The second phase, which starts when the dipolar mode vanishes, is quite faster: 10,000 years are required for the dipole to recover with the opposite polarity. Sometimes, at the end of the first phase, the system may simply return to the initial pole, which is called an “excursion” when it occurs on Earth. However, if the system does reverse, the behavior happens relatively abruptly. In addition, the system usually overshoots immediately after reaching the opposite pole.
The scientists noted that the amplitude of the fluctuations does not need to be large: “Fluctuations of the flow do not switch off the magnetic field and then regenerate it with the opposite polarity,” they said. “In contrast, the dipolar field continuously changes shape during a reversal because the amplitude of the other mode (the quadrupole, for instance) continuously increases, whereas the dipole decreases. When the dipolar component vanishes, it can increase again with the opposite polarity whereas the amplitude of the other mode decreases.”
The model shows that the duration of the magnetic field in one state depends on the intensity of the convection fluctuations and also on the efficiency of the coupling between the two modes. Even a moderate change in convection can greatly affect the magnetic field polarity duration, which could account for “superchrons” - very long periods without geomagnetic reversals. Although little is known about the actual flow inside the Earth’s core, recent observations have shown that the ends of superchrons are often followed by major flood basalt eruptions, which are likely to produce equatorial symmetry breaking of convection at the core-mantle boundary, in support of the scientists’ model.
More information: Pétrélis, François; Fauve, Stéphan; Dormy, Emmanuel; and Valet, Jean-Pierre. “Simple Mechanism for Reversals of Earth’s Magnetic Field.” Physical Review Letters, 102, 144503 (2009).
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