Science
Related: About this forumEarth's Magnetic Field Is Poised to Flip Upside-Down
Its not something thats ever happened in human history so its not something we think about too often, but Earths magnetic poles flip on a regular basisat least, a regular basis on a geologic scale. And every time the poles flip, the magnetic field that shields our planet from deadly cosmic rays also flips. The next flip, according to new data collected by the European Space Agency, is coming up sooner than scientists expected.
Earth's magnetic field is rooted deep inside the planet. The solid inner core, which is about two-thirds the size of the Moon, is made primarily of iron and is super-heated to almost 10,300 degrees Fahrenheit. Surrounding this solid core is a thick layer made up of iron, nickel, and small amounts of other metals in a liquid state. Differences in temperature, pressure, and the composition of the outer, liquid core causes convection, and as these metals flow, they generate electric currents that in turn produce magnetic fields. Because the Earth is spinning on its axis, these magnetic fields align to form one giant magnetic field that envelops the planet.
But the polarity of this massive magnetic field isnt constant. Over the last 20 million years the Earth has settled into a pattern wherein the poles change polarity every 200,000 to 300,000 years; magnetic north becomes south and vice versa. Its neither a fast nor a clean process. A flip actually takes hundreds of thousands of years, and over the course of that time the magnetic fields tug at one another, with magnetic poles emerging at odd latitudes.
Its by measuring the variations in the magnetic field that scientists find indications that a polar flip is imminent. ESAs Swarm mission is a magnetic field mission that uses an array of three satellites to unravel the mysteries of the Earths magnetic field.
Recently, big weak spots in the magnetic field more than 370,000 miles above the planet's surface have sprung up over the Western Hemisphere. Meanwhile, the magnetic field has strengthened in other areas, like over the southern Indian Ocean. Scientists behind the Swarm missions aren't entirely sure why the magnetic field is weakening in certain spots, but the likeliest explanation is that the poles are getting ready to flip. So far, it looks like the poles are just starting to migrate a little bit.
more
http://motherboard.vice.com/read/get-ready-for-earths-magnetic-field-to-flip-upside-down?trk_source=popular
arcane1
(38,613 posts)kimbutgar
(21,137 posts)It would be catastrophic and result in billions of deaths in the world.
Louisiana1976
(3,962 posts)BlueJazz
(25,348 posts)muriel_volestrangler
(101,311 posts)and no, it won't be catastrophic. As the article says, they've happened many times in the past several million years, and there's no sign of extinctions associated with them. A theory says that the solar wind induces a protective layer in the ionosphere during the time the field is flipping:
http://www.aanda.org/articles/aa/abs/2004/23/aagb091/aagb091.html
The Velveteen Ocelot
(115,683 posts)Will there be a loud "BOINNNG!" when this happens, and will it cause some weird, massive electrical current, like the whole earth is a gigantic field winding? Will everybody's hair stand on end? Will we get Raptured? Will all the compasses start pointing in the opposite direction?
Or will it be gradual and boring and not especially noticeable?
jakeXT
(10,575 posts)http://www.cbsnews.com/news/earths-magnetic-field-is-weakening-10-times-faster/
DavidDvorkin
(19,475 posts)Except in that other hemisphere, where they will become us.
jakeXT
(10,575 posts)sue4e3
(731 posts)we have 2,000 years , from other articles we have anywhere from 250 years to 4,000 for the magnetic north and south to flip either way I don't plan on being here.
The Blue Flower
(5,442 posts)I need someone to explain what we're using to measure the magnetic field at a distance of 370,000 miles, well past the orbit of the moon. Could it be a typo?
Enthusiast
(50,983 posts)Just wondering.
awoke_in_2003
(34,582 posts)will be seriously inaccurate.
Duppers
(28,120 posts)The magnetic field gives rise to the electric field, soooo a lot of electronics will mess up. How badly depends on the speed of the flip.
PADemD
(4,482 posts)mindwalker_i
(4,407 posts)They apply a magnetic field, then reverse it, reverse again, etc. Water molecules have a magnetic reactivity of about 80, so they flip with the changing magnetic field, causing friction. Iron has a magnetic reactivity of about 4000 which is why putting iron (or steel) in a microwave is discouraged.
so what this all means is that the Earth is a giant, low-frequency microwave and we're all going to be (slowly) cooked by the changing magnetic field.
It'll also make electrons gay.
n2doc
(47,953 posts)Martin Eden
(12,864 posts)The theory of "continental drift" was advocated by Alfred Wegener in the 1920's, but he was scoffed at by most of the scientific community because he provided no mechanism for the movement of continents. After WWII with the advent of technology for mapping the ocean floor, the Mid-Atlantic Ridge was discovered. As magma surged from the ridge it produced new sea floor, widening the Atlantic and moving the Americas and Europe/Africa further apart.
When new sea floor is produced, the rock is magnetized according to the direction of the earth's magnetic poles. When the poles flipped this was recorded in the rock, and when examined it showed stripes like an irregular barcode moving away from the Mid-Atlantic Ridge where new sea floor was being produced. This not only clearly demonstrated the sea floor was moving, it also provided the rate of expansion because of the timeline for polar shifts known by geologists.
groundloop
(11,518 posts)(Is the thingy even needed?)