Page 2 - Did you know the Earth's Magnetic Field Reversed?

I agree wholeheartedly. I have GPS available on my cell phone and never use it-- GPS is a good way to pinpoint oneself on a map, but who carried freakin' maps around? Only those losers who have compasses on them as well as GPS receivers.

For everyone else, it tells them with high precision that they are still lost.

I love my GPS if you drive around Louisiana as much as I do
and with all the signs STILL down you would get one too.
Every crew member I have has bought one out of their own pocket to have one.

Just try using GPS in the woods!!
The problem is when people rely entirely on GPS without understanding its limitations.

well i just learned about this in my high school physics class.
but does anyone know why this happens?

GPS works off satilite it does not care woods or ocean the limitation is in PEOPLE.
D1 said I always carry maps and compass,but I also carry water, food, a lighter and a cell phone with GPS maps, 911 locater and a camera.
I constantly preach being prepared, and the first thing is to think before acting.
But truthfully if you dropped me anywhere in the world naked (evil mind picture ha ha )
I could figure out where I was and in which direction to go, what to do, and how to SURVIVE.

Haha! See, I told you guys, what a total loser!

Oh, and CY? Tell us a story!

I am 1 out of 7 people so far that didnt know this.....glad someone shared the secret.

Hey, I know I'm late, but I missed this hehe.

You know, I have been reading alot lately about the Solar Cycle. The cycle has been gaining in intensity over the past century. So I guess this doesn't surprise me. Its going to get pretty hot around here in 2011. Dime to a dollar, we're going to hear about how we've killed ourselves with our lust for horsepower.

But its like something from a sci fi novel.. the sun getting hotter and hotter, inexplicably before its time...


And you know what, I think I just came up with a new spin on the solar sci fi idea... ^_^ *writes it down*

Haha, I knew that. I hope it flips in our lifetime. That'd be sweet. Then North would really be North!

I knew it ,on these my physics teacher has the credit ,but there are weak chances that this to happen in our life because this not happens from a day to other.



These can be read at , so all who did not know about these read it!

science.nasa .gov/headlines/y2003/29dec_magneticfield.htm ( delete that space prior the period))
But maybe you live forever and on these case:
SO just think about what can bee done on these special years, you could go to Tahiti and visit the Northern pole

Its an interesting article and geodynamo models are a fantastic tool, but what a lot of people forget is that they are models. They make a lot of predictions which fit well with the observed data, but do not necessarily exhibit complete Earth like behaviour. Values used to model the dynamo can be different to values seen in the Earth by a factor of up to 1 billion!! So there is still a long way to go.

How the direction of the geomagnetic field varies with time is fairly well know, but in order to understand the full long term behaviour we also need to know how the field strength varies with time.... and that is quite difficult.

If you take the latest database of field strength values (known as palaeointensities) it has 3128 points spanning around 4 billion years (Perrin & Schnepp, 2004). If you reduce the data set to data obtained using methods which are accepted as being more reliable then you are left with only 1516 points.
I won't go into details but the spatial distributions is very poor. And as for the temporal distribution... one third are from the last 100kyr, with 60% from the last 1Myr.

In short the resolution is not there to be able to draw any conclusions about the long term variability in the strength of the geomagnetic field.
There is a heck of a lot of work to do!



Perrin, M. and Schnepp, E., (2004). IAGA paleointensity database: Distribution and quality of the data set, Phys. Earth Planet. Int., 147 (2-3, Spec.Iss.), 255-267.

Can we have more than 1 north pole ???
That would be interesting.

Strictly speaking we do have more than one north pole. There is geographic north, magnetic north and geomagneic north.

Geographic north is the northern most point on the globe.

Magnetic north is where the magnetic field line point straight down.

Geomagnetic north is the magnetic north if the Earth's magnetic field where to be modelled by a best fit dipole (imagine a bar magnetic at the centre of the Earth; its pretty good approximation).

At the moment the geomagneitc field is predominantly dipolar (~75-90%) that why we only see one north and one south pole. During a magnetic reversal the field strength decreases so the effects of of non-dipole terms become more significant, relatively speaking. This makes the field at the surface more complicated with quadrupoles and octupoles (as well as higher order terms) producing mutiple poles.

If that ever did happen..... pity the pigeons!!

Yeah...I found out about 5 years ago in the science channel...I was bored.

Hmmmm.......

Well, the Mayans were obsessed with time keeping, and this involved lunar and solar cycles. In fact they have a calendar thats thousands of years old, it's so damn precise.

Theres just one small problem.

For some reason it stops on December 21st 2012.....

Just google it. The History Channel did a seriously good documentary on it.