Solar Flares

[shadron]

What causes the earth to produce a magnetic field? Hot molten lava rotating in the earth. For the poles to flip this rotation has to change direction. For that to happen it would have to stop, and start again..no that couldn't work. It wouldn't stop rotating and then start again. I don't believe that the laws of nature allow that. I think the reversal would occur by the north pole moving south on one side of the planet, and the south pole moving north on the opposite side.

Actually, no. Lava is not magnetic. The liquid that causes the Earth's field is the outer core, of molten iron. Unfortunately, the liquid is not a laminar flow; it is turbulent, including convection currents, incoming heavy metals settling to the center and so on.

Got it. All the drawings I've seen show the magnetic field from the south shooting away from the north and eventually coming back around half circle to the north. Pic.

Currently the CME's hit the earth close to the center of the north and south poles, where the strength is the strongest? What if the pole was facing the sun, would it's protective properties be decreased?

Charged particles in a magnetic field can travel freely (neither gain nor loose energy) by traveling along the lines of the field. Particles from the sun, typically protons, blast through the outer layers of the field until their kinetic energy is absorbed, and then they flow along the field lines. Two things happen at the poles: the particles begin to concentrate as the lines concentrate; since they are all charged identically, they repel each other, so they tend to oscillate from pole to pole, and they also move around the Earth through lines of equal potential. Secondly, when they begin to approach a pole they start colliding with molecules in the air, loosing their energy to them, and fluorescing as auroras.

 

[Skeptic Ginger]

What causes the earth to produce a magnetic field? Hot molten lava rotating in the earth. For the poles to flip this rotation has to change direction.

No, that is not what happens any more than every 11 years the internal plasma rotation within the Sun reverses direction. The force reverses, the direction of rotation of the molten components in the Earth's core do not change direction.

Currently the CME's hit the earth close to the center of the north and south poles, where the strength is the strongest? What if the pole was facing the sun, would it's protective properties be decreased?

No, the CMEs hit the Earth straight on (or a glancing blow, whatever). It is the magnetic field that curves the direction of the particles hitting the atmosphere.

 

[Skeptic Ginger]

A start: Geomagnetic excursion^WP

That's nice but what about the Geomagnetic reversal^WP?

 

[macdoc]

Good visual and explanation here.

http://www.pbs.org/wgbh/nova/magnetic/reve-drives.html

and here

http://nationalatlas.gov/articles/geology/a_geomag.html

and here - including specifically reversals

http://www-istp.gsfc.nasa.gov/Education/FAQs1.html#q1

 

[aggle-rithm]

Awesome, thank you! I read this one dumbe site that claimed it COULD wipe out all life on earth if big and direct enough, and people are affected emotionally and physically by them.

Not directly, but if it takes out the electrical grid the humans are in big, big trouble...

 

[Zeuzzz]

Not directly, but if it takes out the electrical grid the humans are in big, big trouble...

Only humans stupid enough to still be using the energy grid thats been long monopolised by current energy industries. There are alternative energy generation/transfer methods now basically the same price, in some cases cheaper, than would cost plugging into the grid.

 

[aggle-rithm]

Only humans stupid enough to still be using the energy grid thats been long monopolised by current energy industries. There are alternative energy generation/transfer methods now basically the same price, in some cases cheaper, than would cost plugging into the grid.

Are the water companies using this alternative energy? We can do without lights and television and computers, but we need water to survive.

ETA: Also, there's no way we could distribute all the food for all the people in the developed world without the processing/manufacturing infrastructure that depends on the power grid.

In time, we could adapt to a life without electricity, but not before a LOT of people are dead.

 

[aggle-rithm]

Also, the alternative power sources would probably also be destroyed. You could fix it if you could get parts, the manufacture of which depends heavily on the grid.

 

[ServiceSoon]

Actually, no. Lava is not magnetic. The liquid that causes the Earth's field is the outer core, of molten iron. Unfortunately, the liquid is not a laminar flow; it is turbulent, including convection currents, incoming heavy metals settling to the center and so on...

Isn't it the combination of the inner and outer cores that causes the earth's magnetic field? Similar to how we generate electricity?

...Charged particles in a magnetic field can travel freely (neither gain nor loose energy) by traveling along the lines of the field. Particles from the sun, typically protons, blast through the outer layers of the field until their kinetic energy is absorbed, and then they flow along the field lines. Two things happen at the poles: the particles begin to concentrate as the lines concentrate; since they are all charged identically, they repel each other, so they tend to oscillate from pole to pole, and they also move around the Earth through lines of equal potential. Secondly, when they begin to approach a pole they start colliding with molecules in the air, loosing their energy to them, and fluorescing as auroras.

Huh? I'll have to take a look at Madoc's information to gain more knowledge on this topic.

 

[Cuddles]

I think Phil did cover this in his latest book, "Death from the Skies"

Yes, Phil Plait did cover this and yes, a CME could wipe us out. It's not magnetic fields you need to worry about, it's chemistry. A direct hit by a large CME could pretty much wipe out the entire ozone layer. The resulting increase in UV reaching the surface of the Earth would be devastating for almost all life, since it would kill the majority of photosynthetic life and cripple most food chains. It would kill off a lot of land based life (including us) rather more directly, but that would just speed things up a bit rather than making any real difference.

As for the argument that life has been around for a while without this happening, it's entirely possible it actually has happened before, and was the cause of one or more mass extinctions. It's unlikely to wipe out all life, but it certainly wouldn't be good for us squishy humans.

The important point to bear in mind is that effects of this magnitude require a really, really big CME. Even the biggest ones we've seen since we've been looking would manage little more than killing satellites and messing up some electronics. Still potentially dangerous and rather expensive, but far from a threat to civilisation, let alone life as we know it. An extinction causing CME is a possibility, but it's not exactly the kind of thing you should stay up at night worrying about.

As for all the silliness about effects on emotions and planetary alignments, yeah, that's nonsense.

 

[Dr.Sid]

Such CME did not yet happened. Chances are it won't happen in the future. Actually I'm more afraid about asteroids and them human robots.

 

[shadron]

That's nice but what about the Geomagnetic reversal^WP?

So? Is it a problem that the findings overlap and are ambiguous? All that I said is that some of the latest research seems to indicate that reversals might not collapse the whole of the magnetic field around Earth, leaving it unprotected; which position is compatible with the fact that reversals as placed by the geologic record don't seem to signal any sort of extinction event.

A warning about accepting any description (let alone theory) about the Earth's magnetic field too readily yet:

Present computational methods have used very strong simplifications in order to produce models that run to acceptable time scales for research programs.

The reversals weren't known until the 20s, and not investigated until the study of plate tectonics began in the 50s. Excursions have been discovered in the last ten years. At least one other body, the sun, has reversals which do not diminish the strength of its field; in fact, they increase it. The geology of the magnetic field is in a frontier state in which we only now know the most basic parts. In the coming tens of years much more remains to be learned.

 

[Skeptic Ginger]

... All that I said is that some of the latest research seems to indicate that reversals might not collapse the whole of the magnetic field around Earth, leaving it unprotected; .....

I was under the impression you were claiming more certainty than, "might".

The current theory about pole reversals doesn't include as a major part the reduction of the field strength to zero. Rather, it involves local disoganization of the field, so that there are essentially a plethora of north and south poles in the middle time. That we see single north and south poles apparently is just a measure of the more usual alignment of local fields.

My objection is your claim this is, "the current theory" as opposed to, "this is one theory".

 

[Corsair 115]

In fact, I'll bet my life savings that nothing will ever wipe out life on Earth.

A big enough asteroid or comet impact would do it. Those are very rare events however.

 

[Hellbound]

A big enough asteroid or comet impact would do it. Those are very rare events however.

Hmmm. There's evidence now that the vast majority of biomass exists under the surface of the Earth, in the form of bacteria that live on various compounds in rock and soil. Not to mention places like deep-sea vents miles below the oceans surface with pyrophilic bacteria. It'd have to be hella-big to take all that out along with everything else. I'd suspect it'd have to be big enough to pretty much break the Earth's crust open to completely take out everything.

Course, not that it'd matter any more to me (or anyone else), but life is kinda life a mold problem. Once it gets all over your house, about the only way to get rid of all of it is to tear the house down and start over

 

[shadron]

I was under the impression you were claiming more certainty than, "might".

My objection is your claim this is, "the current theory" as opposed to, "this is one theory".

Well, would a three year sentence to the CT forum with two years off for good behavior handle it? I promise that won't never, ever overstate my case ever again. Please??? I don't wanna be late for my own funeral, you understand.

(No, no, just a joke - no premonitions.)

 

[Corsair 115]

Hmmm. There's evidence now that the vast majority of biomass exists under the surface of the Earth, in the form of bacteria that live on various compounds in rock and soil. Not to mention places like deep-sea vents miles below the oceans surface with pyrophilic bacteria. It'd have to be hella-big to take all that out along with everything else. I'd suspect it'd have to be big enough to pretty much break the Earth's crust open to completely take out everything.

I remember a link to a web site which allowed one to enter in some criteria about the impacting object, such as size, velocity, and angle of impact, and the resulting physical effects, such as the brightness and temperature of the impact, would be calculated, and the practical results displayed (e.g. how much of the oceans would be boiled away, how far away you had to be to avoid being blinded, etc.).

If I recall correctly, an asteroid on the order of 100-200 miles in diameter was large enough to pretty much sterilize the entire Earth. Might have been somewhat larger, I can't really remember for sure.

 

[Hindmost]

Yes, Phil Plait did cover this and yes, a CME could wipe us out. It's not magnetic fields you need to worry about, it's chemistry. A direct hit by a large CME could pretty much wipe out the entire ozone layer. The resulting increase in UV reaching the surface of the Earth would be devastating for almost all life, since it would kill the majority of photosynthetic life and cripple most food chains. It would kill off a lot of land based life (including us) rather more directly, but that would just speed things up a bit rather than making any real difference.

As for the argument that life has been around for a while without this happening, it's entirely possible it actually has happened before, and was the cause of one or more mass extinctions. It's unlikely to wipe out all life, but it certainly wouldn't be good for us squishy humans.

The important point to bear in mind is that effects of this magnitude require a really, really big CME. Even the biggest ones we've seen since we've been looking would manage little more than killing satellites and messing up some electronics. Still potentially dangerous and rather expensive, but far from a threat to civilisation, let alone life as we know it. An extinction causing CME is a possibility, but it's not exactly the kind of thing you should stay up at night worrying about.

As for all the silliness about effects on emotions and planetary alignments, yeah, that's nonsense.

What if a CME the magnitude of the one in 1859 was to hit earth again...what would be your evaluation? I really don't know what the effect would be, but I would be concerned about the vulnerability of the grids around the world.

glenn

 

[shadron]

Yes, Phil Plait did cover this and yes, a CME could wipe us out. It's not magnetic fields you need to worry about, it's chemistry. A direct hit by a large CME could pretty much wipe out the entire ozone layer. The resulting increase in UV reaching the surface of the Earth would be devastating for almost all life, since it would kill the majority of photosynthetic life and cripple most food chains. It would kill off a lot of land based life (including us) rather more directly, but that would just speed things up a bit rather than making any real difference.

As for the argument that life has been around for a while without this happening, it's entirely possible it actually has happened before, and was the cause of one or more mass extinctions. It's unlikely to wipe out all life, but it certainly wouldn't be good for us squishy humans.

I think the largest argument against this scenario is that it would have been a virtual one-off for the sun, and the explanation as to why that should happen is lacking. As you say it would have had to have been a monstrous event. There is a theory that the End-Ordovician extinction may have been because of a nearby (within 6,000 ly) GRB that happened to have it's crosshairs on our planet, and it's ten second blast resulting in the same scenario you describe. There's a description of the occurrance in an Animal Planet hour-long which recently made a reappearance on YT:

http://www.youtube.com/user/Zuke969#g/c/71ACA91569A61953

We won't be able to settle whether or not the GRB happened as shown until we get men on the moon and do some specific looking for isotope layers. Probably such a solar event would also leave traces.

 

[Skeptic Ginger]

If the thread is now about extinction scenarios, I'll toss in that we don't know what happened only a few 100 million years ago that completely resurfaced Venus. And since we don't understand the geological mechanism, we can't say it can't happen here.

The global resurfacing of Venus

The constraints imposed by the cratering record strongly indicate that Venus experienced a global resurfacing event about 300 m.y. ago followed by a dramatic reduction of volcanism and tectonism. This global resurfacing event ended abruptly (<10 m.y.). The present crater population has accumulated since then and remains largely intact. Thermal history models suggest that similar global resurfacing events probably occurred episodically in the past.

And lest you think it can't happen here:

Episodic regional resurfacing events that had global effects also occurred on Earth (e.g., the mid-Cretaceous superplume) and probably on Mars. On Mars they may have triggered the catastrophic releases of water that formed the outflow channels.