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Thread: Magnetic reversal coming?

  1. #1
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    Magnetic reversal coming?

    This is Zero Hedge, so he says this will be TEOTWAWKI. Nah, we survived the Laschamp Event just fine.
    But is he right that the weakening of the field is accelerating?
    https://www.zerohedge.com/news/2019-...ly-accelerated
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

  2. #2
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    The guy at Zero Hedge looks like he drinks more Espresso than the gal at Live Science. Jonathan O'callaghan at phys.org and Kelly Dickerson at Scientific American both have enigmatic non-visages.
    Looks like it's a crap shoot to me, and will remain one until we see one and can get the data.
    Last edited by Squink; 2019-Apr-15 at 01:12 AM.

  3. #3
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    I cannot acknowledge 'zerohedge' as anything more than a fanatic. For geological information, I prefer sources such as the USGS:

    https://www.usgs.gov/faqs/are-we-abo...ience_products

    The answer is no.

  4. #4
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    Quote Originally Posted by Tom Mazanec View Post
    But is he right that the weakening of the field is accelerating?
    The weakening is irrelevant for a magnetic field that varies a lot without meeting the criteria for a geomagnetic reversal as the USGS site states. Also see Earth's magnetic field is not about to reverse where two close to reversal events are noted.
    A study of the most recent near-reversals of the Earth's magnetic field by an international team of researchers, including the University of Liverpool, has found it is unlikely that such an event will take place anytime soon.

    There has been speculation that the Earth's geomagnetic fields may be about to reverse , with substantial implications, due to a weakening of the magnetic field over at least the last two hundred years, combined with the expansion of an identified weak area in the Earth's magnetic field called the South Atlantic Anomaly, which stretches from Chile to Zimbabwe.

    In a paper published in the Proceedings of the National Academy of Sciences, a team of international researchers model observations of the geomagnetic field of the two most recent geomagnetic excursion events, the Laschamp, approximately 41,000 years ago, and Mono Lake, around 34,000 years ago, where the field came close to reversing but recovered its original structure.
    Laschamp event was the magnetic field reversing for ~440 years and recovering. This is called a geomagnetic excursion in contrast to a reversal.

  5. #5
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    Quote Originally Posted by Reality Check View Post
    The weakening is irrelevant for a magnetic field that varies a lot without meeting the criteria for a geomagnetic reversal as the USGS site states. Also see Earth's magnetic field is not about to reverse where two close to reversal events are noted.

    Laschamp event was the magnetic field reversing for ~440 years and recovering. This is called a geomagnetic excursion in contrast to a reversal.
    I think that 440 years might cause "substantial implications". Not calling it a reversal for vague (to the rest of the world) scientific reasons, doesn't mean it won't actually physically be a reversal does it? We can celebrate the Geomagnetic excursion by knowing we'll have to go through it all again relatively soon.

  6. #6
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    Quote Originally Posted by headrush View Post
    I think that 440 years might cause "substantial implications".
    There are empirical working definitions where a geomagnetic reversal is a reversal that stays reversed for hundreds of thousand to millions of years. A geomagnetic excursion of 440 years is not a reversal. Zero Hedge is thus ignorant about geological terms and so not a reliable source.
    The distinction between geomagnetic excursions and reversals (1999)
    These observed phenomena have some empirical working definitions. Intervals of constant polarity are called chrons, subchrons, and superchrons, depending on their duration. Excursions take place within these intervals. They have been distinguished from typical secular variation in the historical record, when the field is dominated by a GAD, using the angular departure of the field direction from that of a GAD. For example, Verosub (1977) defined an excursion to be when the virtual geomagnetic pole (VGP) was more than 45° from the geographic pole. Excursions have been distinguished from a pair of reversals by their duration: if the two reversals are not included in the accepted reversal timescale, they constitute an excursion. Cande & Kent (1992) used a limit of 30kyr in their recent reversal timescale.
    Geomagnetic Excursions (PDF) has Table 1, a list of the definitions.

    Also note that geomagnetic excursions can be local or global.

    Quote Originally Posted by headrush View Post
    ...knowing we'll have to go through it all again relatively soon.
    We do not know that. We know is that it is unlikely that the current decrease in the magnetic field will lead to the field reversing: Earth's magnetic field is not about to reverse. This study explicitly states no geomagnetic exclusion is likely. The current changes in the geomagnetic field do not resemble the changes preceding the 2 events they looked at.

    P.S. The answer to the question "But is he right that the weakening of the field is accelerating?" is: He is wrong. He is misusing a hyped misinterpretation of early SWARM data to make a mass extinction fantasy.
    Is Earth's Magnetic Shield Eroding? (the answer is yes over the last 3 centuries but not accelerating)
    What SWARM has actually found is that after 2.5 years of observation, the Earth’s magnetic field has weakened by about 3.5% at high latitudes over North America, while it has strengthened about 2% over Asia. In other words, it wiggles and wobbles. We already knew that. The articles announcing the 5% per decade decline all appear to have arisen six months after SWARM launched, and appear to have misinterpreted early findings.

    That said, the Earth’s magnetic field is weakening, and whether it collapses in the next two thousand years or the next two, it will eventually collapse and flip as it seems to have done regularly for many millions of years. But not to worry. Contrary to what you see in the movies, the field collapse will not lead to calamity for life on Earth. It’s happened hundreds of times before, and there is absolutely no evidence that it has ever caused a mass extinction or even a noticeable disruption to life on Earth.
    Also see No, We're Not All Doomed by Earth's Magnetic Field Flip. There may be some technological impacts but we should have plenty of time to prepare for them.
    Last edited by Reality Check; 2019-Apr-17 at 01:07 AM.

  7. #7
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    Quote Originally Posted by Reality Check View Post
    There are empirical working definitions where a geomagnetic reversal is a reversal that stays reversed for hundreds of thousand to millions of years. A geomagnetic excursion of 440 years is not a reversal. Zero Hedge is thus ignorant about geological terms and so not a reliable source.
    The distinction between geomagnetic excursions and reversals (1999)


    Geomagnetic Excursions (PDF) has Table 1, a list of the definitions.

    Also note that geomagnetic excursions can be local or global.


    We do not know that. We know is that it is unlikely that the current decrease in the magnetic field will lead to the field reversing: Earth's magnetic field is not about to reverse. This study explicitly states no geomagnetic exclusion is likely. The current changes in the geomagnetic field do not resemble the changes preceding the 2 events they looked at.

    P.S. The answer to the question "But is he right that the weakening of the field is accelerating?" is: He is wrong. He is misusing a hyped misinterpretation of early SWARM data to make a mass extinction fantasy.
    Is Earth's Magnetic Shield Eroding? (the answer is yes over the last 3 centuries but not accelerating)

    Also see No, We're Not All Doomed by Earth's Magnetic Field Flip. There may be some technological impacts but we should have plenty of time to prepare for them.
    There's always the 10 km magnetized iron meteorite that is repelled by earth's bipolar magnetic field but not by the wimpy quadrupole field that forms during the field reversal process.
    You can almost always find a way to doom us utterly.

  8. #8
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    Quote Originally Posted by Squink View Post
    There's always the 10 km magnetized iron meteorite that is repelled by earth's bipolar magnetic field but not by the wimpy quadrupole field that forms during the field reversal process.
    I may be completely wrong, but I assume that the meteorite, if magnetic, would have a north and South Pole, and would most likely be spinning so that it would not be either attracted or repelled. And in any case, the earth’s magnetic field is much to weak to have any significant effect on a large meteor.


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  9. #9
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    Quote Originally Posted by Jens View Post
    would most likely be spinning so that it would not be either attracted or repelled.
    How can we be utterly doomed if you are going to assume such a likely scenario?

    My point is that there's a narrow window through which a magnetic reversal might just do us in.
    A mega CME, or a supernova mean pointed in just the wrong direction while our field is at minimum are two other possibilities.
    Sure, probability is far, far on our side, but it's not a certainty.

  10. #10
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    Quote Originally Posted by Squink View Post
    How can we be utterly doomed if you are going to assume such a likely scenario?
    Bender: (inhales)
    Bender: DOOOOOOOOOOOOOO(scene ends)
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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