Hypothetical discussion on the effect of magnetic fields on planets

[Epsilon Eridani]

TL;DR

Discussion on what would happen if the magnetic field of a bio-rich planet like Earth gets disturbed

Ok, so I have long been fascinated with magnetic fields and their mysterious nature. I've been wondering what would happen when the magnetic field of Earth gets bent/disturbed/rippled by some extraneous force. I am aware the extent of effects that magnetic fields have on a planet is great, but I am not really sure what would happen to say Earth, for example, if an alien object would be put in its vicinity, ravaging the magnetic field of the planet. Can someone with a deeper understanding of the topic shed some light on what would happen following such an event?

 

[berkeman]

Summary:: Discussion on what would happen if the magnetic field of a bio-rich planet like Earth gets disturbed

Ok, so I have long been fascinated with magnetic fields and their mysterious nature. I've been wondering what would happen when the magnetic field of Earth gets bent/disturbed/rippled by some extraneous force. I am aware the extent of effects that magnetic fields have on a planet is great, but I am not really sure what would happen to say Earth, for example, if an alien object would be put in its vicinity, ravaging the magnetic field of the planet. Can someone with a deeper understanding of the topic shed some light on what would happen following such an event?

Welcome to the PF.

It's hard to picture some realistic scenario where the Earth's magnetic field changes by much at the surface of the Earth, without something else big happening. For an object to come close enough to the Earth to change the B-field at the surface, it would probably have other bad effects as well.

You do know that the Earth's B-field does change slowly over time, right? And things seem to survive okay...

https://en.wikipedia.org/wiki/Earth's_magnetic_field

 

[Epsilon Eridani]

For the sake of hypothetical discussion, assume nothing big is happening, no foreign object is present, and not just the surface is changing, but the entire shape of the field is being suddenly thrashed and morphed into something that has no resemblance to how it usually is. What effects would be observed on all life and climate on the planet?

 

[berkeman]

For the sake of hypothetical discussion, assume nothing big is happening, no foreign object is present, and not just the surface is changing, but the entire shape of the field is being suddenly thrashed and morphed into something that has no resemblance to how it usually is. What effects would be observed on all life and climate on the planet?

We don't generally start discussions like that. They are ill-defined and generally not productive. Anything that can make those kind of changes to the B-field will most likely have other effects that will probably dominate the B-field secondary effects.

Take the solar wind effects described in the Wikipedia article that I linked. Those have lots of other effects beyond just the small B-field effects at the Earth's surface.

 

[Epsilon Eridani]

Ok, let me phrase the question differently then - what existing systems on Earth that are crucial to the fine balance between biomes and in general the processes that take place in the planet's tectonic layers, atmosphere, and general life-support systems, are entirely dependent on the stability and shape of the magnetic field, and would severely change if that field gets distorted?

 

[jim mcnamara]

How about removal of the magnetic field because the Earth's core ceased generating the field?
Answer: Mars.
https://phys.org/news/2020-05-timeline-ancient-magnetic-field-mars.html

How about a short term major perturbation? Not hypothetical at all...

Answer:severe geomagnetic storm -- it would likely trash satellites and some of the internet, and until we get our act together, severely damage the electric grid. It does not harm life as far as is known. This happened in 1859. Medium sized CME caused a 'the great blackout' in the US Northeast in 1965.

See: https://www.historycentral.com/sixty/Tech/blackout.html

See the Carrington Event, fun read:
https://en.wikipedia.org/wiki/September_1859_geomagnetic_storm

X class CME (coronal mass ejection):
https://en.wikipedia.org/wiki/Coronal_mass_ejection

 

[Baluncore]

I've been wondering what would happen when the magnetic field of Earth gets bent/disturbed/rippled by some extraneous force.

That happens every 125,000 years on average when the Earth's magnetic field reverses.
The last change was over 800,000 years ago, so it is now long overdue.
Ask yourself what is expected, or likely to happen when it does flip.

 

[jim mcnamara]

Cool chart of magnetic fields reversals for the past 5 million years:
https://en.wikipedia.org/wiki/Geomagnetic_reversal

 

[Epsilon Eridani]

Very interesting stuff. So basically the magnetic field is entirely controlled by the dynamo. Can humans impact that by placing a gigantic magnet near the planet for example? I know this is all very unrealistic but I'm just curious to what extent can humans have an impact on the field.

 

[Baluncore]

Can humans impact that by placing a gigantic magnet near the planet for example?

We can add or subtract from the field at the surface by pushing an electric current through loops of conductor, or transmitting radio waves. But the time needed to change the internal field is four times longer than we have had an electric power industry.
(Wikipedia says; “Diffusion in the liquid outer core is on timescales of 500 years or less, while that of the solid inner core is longer, around 3000 years”.)

 

[Dale]

There wouldn’t be much in the way of biological effects. This has happened many times in the past.

I would expect that there would be some economic effects. People panic buying toilet paper for instance. Tin foil hat companies by the dozens. Shortages of sunscreen, and toxic sunscreens rushed to market. Basically what we are seeing now, but slightly different.