Earth's weakening magnetic field/solar storms

This is a great place to post questions and answers about the Sun.
Post Reply
Phobos
Posts: 30
Joined: Thu Oct 19, 2017 2:54 pm

Earth's weakening magnetic field/solar storms

Post by Phobos » Wed Feb 21, 2018 12:02 pm

Hope I'm not bombarding you with questions, Lisa! Apparently, Earth's magnetic field is weakening quite rapidly. So does that mean that minor solar storms can impact the grid, and be capable of causing more outages?

User avatar
lisa
Site Admin
Posts: 25
Joined: Tue Oct 10, 2017 6:28 pm

Re: Earth's weakening magnetic field/solar storms

Post by lisa » Sat Feb 24, 2018 4:43 am

Hi Phobos,

Not at all!!!
Apparently, Earth's magnetic field is weakening quite rapidly. So does that mean that minor solar storms can impact the grid, and be capable of causing more outages?
So, let's start at taking a look at what this actually looks like. Here's a plot showing the evolution of the Axial Dipole Moment for the Earth's magnetic field:

Image

In this case, time is going from right to left, because it is showing age - so the most recent time is on the far left. As you can see, we've been at a bit of a maximum as far as the Earth's polar field goes, so it makes sense that once the decline starts it would probably be quite rapid. That being said, take a look at the units of the plot. They are 'ka', i.e., thousands of years. So when we say rapid, we're talking on geological time scales! This means, even if we are headed for a reversal, it is not going to happen anytime soon.

In terms of what a reversal means for life on Earth - it will go on. There is evidence that the weakening of the Earth's field has historically been linked to some excess radiation, which can cause mutations and thus spur an enhanced period of evolution. But, there is no indication that it has ever cause any extinction events. In terms of what it might mean to technology, that is anyone's guess - I mean who knows what technology would even look like when it does finally occur!! However, here's a couple interesting articles that discuss what it might look like if it *were* to happen any time soon:

https://www.scientificamerican.com/arti ... -expected/
https://www.quora.com/What-will-happen- ... -our-hands

I hope this helps!

Cheers!
-Lisa

Phobos
Posts: 30
Joined: Thu Oct 19, 2017 2:54 pm

Re: Earth's weakening magnetic field/solar storms

Post by Phobos » Sat Feb 24, 2018 12:38 pm

This is really interesting, thanks!

Phobos
Posts: 30
Joined: Thu Oct 19, 2017 2:54 pm

Re: Earth's weakening magnetic field/solar storms

Post by Phobos » Sun Feb 25, 2018 12:49 pm

I have another question which is most probably totally off the wall, and please feel free to ignore it. :-) But is there any possibility that solar activity could cause Earth's mag field to reverse, and are reversals or magnetic excursions on Earth more likely to happen when solar activity is low?

User avatar
lisa
Site Admin
Posts: 25
Joined: Tue Oct 10, 2017 6:28 pm

Re: Earth's weakening magnetic field/solar storms

Post by lisa » Mon Mar 05, 2018 10:39 pm

Hi Phobos,

The Earth's magnetic field is generated by the liquid Iron in Earth's core. As the magma that makes up the fluid iron core moves, it generates a moving electric current, which in turn generates Earths magnetic field. (This is know as a dynamo and is also occurring in the Sun). So, the reversals are caused by changes in these motions. Here is a link to a page that describes and illustrates the geodynamo https://websites.pmc.ucsc.edu/~glatz/geodynamo.html. While solar activity can impact the Earth's outer magnetic field, it doesn't really impact the motions of liquid iron in the core, and so the Earth's magnetic reversal are independent of the Solar activity.

Cheers!
-Lisa

Phobos
Posts: 30
Joined: Thu Oct 19, 2017 2:54 pm

Re: Earth's weakening magnetic field/solar storms

Post by Phobos » Wed Mar 07, 2018 8:38 pm

Thanks Lisa!

Post Reply