Magnetic reversals

[Rev. Rex]

In another thread, I mentioned that we are just beginning to understand some cycles, and others we don't know about. Magnetic reversals belong to the former. We know that we have them periodically, on average about every 250,000 years, and that it has been 700,000 years since the last one. We even know that the sun reverses it's magnetic field about every 11 years. We don't know what triggers them, how they actually occur, how long they take, what dangers if any they represent, or how they affect anything else on the planet.

When Compasses Point South


If all the compasses in the world started pointing south rather than north, many people might think something very strange, very unusual, and possibly very dangerous was going on. Doomsayers would have a field day proclaiming the end is nigh, while more rational persons might head straight to scientists for an explanation.

Fortunately, those scientists in the know—paleomagnetists, to be exact—would have a ready answer. Such reversals in the Earth's magnetic field, they'd tell you, are, roughly speaking, as common as ice ages. That is, they're terrifically infrequent by human standards, but in geologic terms they happen all the time. As the time line at right shows, hundreds of times in our planet's history the polarity of the magnetic shield ensheathing the globe has gone from "normal," our current orientation to the north, to "reversed," and back again.

The Earth is not alone in this fickleness: The sun's magnetic shield appears to reverse its polarity approximately every 11 years. Even our Milky Way galaxy is magnetized, and experts say it probably reverses its polarity as well. Moreover, while a severe weakening or disappearance of the magnetic field would lay us open to harmful radiation from the sun, there's little evidence to date that "flips" per se inflict any lasting damage (see Impact on Animals).

It might sound as if scientists have all the answers regarding magnetic reversals. But actually they know very little about them. Basic questions haunt researchers: What physical processes within the Earth trigger reversals? Why do the durations and frequencies of both normal and reversed states seem random? Why is there such a disproportionately long normal period between about 121 and 83 million years ago? Why does the reversal rate, at least during the past 160 million years, appear to peak around 12 million years ago?

All these questions remain unanswered, though experts like Dennis Kent, the Rutgers University geologist who supplied NOVA with updated figures for the time line, are hard at work trying to answer them. In the meantime, not to worry. Reversals happen on average only about once every 250,000 years, and they take hundreds if not thousands of years to complete.

Even the weakening currently under way may be a false alarm. The field often gets very weak, then bounces back, never having flipped. As Ron Merrill, a magnetic-field specialist at the University of Washington remarked when asked whether we're in for a reversal: "Ask me in 10,000 years, I'll give you a better answer." So hang on to your compass. For the foreseeable future, it should work as advertised.—Peter Tyson

http://www.pbs.org/wgbh/nova/magnetic/timeline.html

This is just one of the cycles I referred to in the other thread...cycles that are far stronger than anything that man can do and currently outside his power to change. There are many others. But we know so little about even this one that we have no way to predict what might happen.

[bahai9]

I use a Tate's Compass to help me with directions. Not many were sold, so I guess it's quite a 'collectible'. The needle always point 'N'...no, not to magnetic North, but rather, it always points to the 'N' on the compass.

The company advertises that:

"He who has a Tate's, is lost!"

Hmmm. It must be time for my meds. --Steve--

[RunicSage]

I heard were about ready for a pole shift in the near future globally.

[Rev. Rex]

We simply don't know. All the signs are there. But this has happened before and nothing happened, so we don't know that it will happen. We don't know that the poles are actually reversing. We are over due, and we don't know what will happen if it happens, or if it is happening. If the magnetic field actually collapses, we can expect hole in the ozone layer, and increased rate of skin cancer, increased seismic activity, more extreme weather, climatic shifts....all of which we've seen in the last 10 years, and all without the intervention of man. In fact, man can't change it or stop it. But is magnetic reversal the culprit? The grandfather only knows.

We (the solar system) just also entered the main arm of the galaxy of which we are a part. We also don't know what that means. this hasn't happened in many thousands of years. Will it make a difference? We just don't know.

[RunicSage]

Originally Posted by Rev. Rex

We simply don't know. All the signs are there. But this has happened before and nothing happened, so we don't know that it will happen. We don't know that the poles are actually reversing. We are over due, and we don't know what will happen if it happens, or if it is happening. If the magnetic field actually collapses, we can expect hole in the ozone layer, and increased rate of skin cancer, increased seismic activity, more extreme weather, climatic shifts....all of which we've seen in the last 10 years, and all without the intervention of man. In fact, man can't change it or stop it. But is magnetic reversal the culprit? The grandfather only knows.

We (the solar system) just also entered the main arm of the galaxy of which we are a part. We also don't know what that means. this hasn't happened in many thousands of years. Will it make a difference? We just don't know.

I have heard the heat could be so extreme it could leave little to live or survive by the radiation.

It is one of the many theories I have heard of what could happen.

Then again maybe the opposite could happen for instance another ice age.

[Rev. Rex]

Again, we just don't know. IF the gravitational field collapses, then is recreated, that could very well happen. The Earth's gravitational field is what keeps a lion's share of the radiation and cosmic wind from reaching the surface, so if it collapsed, it would be somewhat similar to being in the inside of a nuclear reactor (not quite as intense, but similar). But we don't know if the field just reverses, or if it does actually collapse first. The sun's field merely flip flops without collapsing. But the sun's magnetic field is created by a different process than ours, and it also reverses much more often...11 years compared to a couple hundred thosand years.

[RunicSage]

Originally Posted by Rev. Rex

Again, we just don't know. IF the gravitational field collapses, then is recreated, that could very well happen. The Earth's gravitational field is what keeps a lion's share of the radiation and cosmic wind from reaching the surface, so if it collapsed, it would be somewhat similar to being in the inside of a nuclear reactor (not quite as intense, but similar). But we don't know if the field just reverses, or if it does actually collapse first. The sun's field merely flip flops without collapsing. But the sun's magnetic field is created by a different process than ours, and it also reverses much more often...11 years compared to a couple hundred thosand years.

Whatever happens the future is looking mighty interesting.