Are we in the midst of a polar magnetic field flip and if so, when will north become south?

It appears we are, but no one knows exactly when or for that matter the speed at which the flip will be achieved. I myself wonder about the implications for the world’s electrical grids and other consequences of the reversal of the earth’s magnetic field.

I’ve heard that the flip could occur rather quickly. Estimates of the effect range from mild to catastrophic.

From what I gather, this hypothesis is not considered very important by mainstream science.

I’ve mainly heard it discussed on the same media that focuses on crypto zoology, UFOs, vampires, ghosts etc.

As with many apocalyptic predictions, we’ll just have to wait and see if the talk is for naught.

I’ll ask my BBE, who is an actual professor of atmospheric science. My thoughts is that it is not in our lifetime and we will have time to prepare.

According to NASA the magnetic pole reversal is a continuous event that takes hundreds of thousands of years to complete.

Sailors have been aware of this since the discovery of the loadstone. It you look at a marine chart, a map of an area of the sea, you will notice off to the side a large, round thing consisting of two concentric circles called a compass rose, which has two Norths. These two concentric circles describe, in degrees from 0 to 360, a compass in relation to the landmarks on the chart. However, each circle, or compass, is a few degrees different from the other.

That is because one of the Norths are what is called True North, or geodetic north. In other words, if you follow that direction you will ultimately arrive at the True geodetic north pole that you see on globes.

The other North is Magnetic North, which points toward the magnetic north pole. If you follow this line, you will end up miles to the left or right of your destination. But, this is where your magnetic compass will lead you, if you do not make an adjustment.

The difference is called deviation and the compass rose allows navigators to adjust their compasses accordingly.

Magnetic North is slowly drifting all the time, so every few years you must buy new charts in order to make the new adjustments and not get lost at sea. This is the magnetic drift—the poles “flipping”—and it has been going on since the beginning of time. It is nothing new, it doesn’t portend catastrophe, nor is it anything to worry about.

We live on a pretty good planet.

Edit: lodestone

When I worked in hydroacoustics there local magnetic declination models that we had to use to correct our magnetic compass readings. It changed enough where I felt like it was worth checking every time we needed to run a profile. Magnetic north and true north are not the same. Magnetic north is in constant flux. A magnetic pole reversal will not happen in an instant. More like tens of decades.

@Espiritus_Corvus Thanks, I knew about magnetic north/true north but did not realize that you had to buy new maps on a regular basis to keep up with the adjustments.
Any idea how this affects an electronic device like a GPS?

They don’t use magnetic north.

Gps devices are triangulated unless it has an integrated fluxgate compass. Those need to be calibrated periodically but it’s easy and usually automated. People do it all the time without realizing that this is what the procedure is

if your car has an integrated compass you (or the dealer) are have already made adjustments for this. As an example, see Instructions for setting Subaru Forester compass.

All three above are correct.

@rojo Well, you really don’t have to buy new charts if you can add and subtract (but it is a good idea because the sea bottom, shoreline, aids and hazards to navigation change over the years).

If you look at the compass rose I linked to above, inside the magnetic compass you will see the notation “Annual Decrease 8 minutes” and above that, the date of the chart, which in this case is 1985. This means you must make a compass correction by 8’ each year after 1985 in order for the rose to be correct and adjust your compass accordingly. This becomes quite significant when sailing long distances.

Due to parallax, the increase or decrease in difference between Mag North and True North is widely varied relative to your position on the globe and therefore you can’t use the compass rose from one chart to another.

Here you have a rose with a 2’ annual increase from a chart of the east coast of Florida. Notice the change in variation as well.

Here is one from the Great Lakes with No Annual Change.

I use GPS only as a back up system to check my course when something doesn’t feel right. I usually sail 1890’s style, by Dead Reckoning when shore is visible, by the compass, or by the charts and celestial bodies. I don’t want to lose that skill. It was good enough for Joshua Slocum and it is good enough for me.

So. This explains why I have to calibrate my compass on my phone? Because of the changes in the magnetic north?

I use a compass when I’m in my canoe,but usually I’m not covering more than 10 miles, and usually just use the compass in a reduced visibility, or walking through swamp.

^^ And that is why @Espiritus_Corvus is my hero!

@MrGrimm Actually, you need to redo it to correct for small errors and drift in the circuitry and minor magnetization of ferrous metals in the phone itself. If you charge your phone the same way, at the same location, in the same orientation, every time the metals will begin to take a set. Remember when you made an electromagnet in junior high school? After you turned off the current the nail was still slightly magnetized. When you charge your phone it is being hit with 3 – 10 watts from the charger. The designers know this and do their best to mitigate the effect but there is still something.
The effect is infinitesimal but so is the magnetic field of the Earth. You cancel it out by turning in circles and following the phone’s stated calibration procedure.

(and why he’s my secret crush)

What BBE quickly said when we last chatted. “The last flip was 50000 years ago, I think. There was some evidence it occurred in less than 100 years.
GPS might be happy. During the flip the magnetic field weakens. So the satellites might not be stuck in a radiation belt. But then they will get more of a direct hit by the solar wind.
GPS navigation won’t change, but compasses will need new labels.”

So, the biggest problem with GPS will be the effect of the upper Earth atmosphere changes on the satellites. GPS satellites are quite low in their orbit. GPS satellites fly in medium Earth orbit (MEO) at an altitude of approximately 20,200 km (12,550 miles). Each satellite circles the Earth twice a day. They are not geosynchronous. Low orbit satellites like weather and communication are low and geosynchronous. All of these satellites will be effected by odd changes in the balance between the two poles due to increased solar radiation exposure. There is a whole branch of science dedicated to upper atmosphere research, and I found out that my BBE can talk about it for a half hour without me knowing or remembering a thing he said. ;P

We argued a bit about the ‘lable’ issue. I don’t think we need to say north is now south and vice versa… it just needs a programming change and kids will grow up learning their compass points South and not North like we did.

Tomorrow.