Solar Flares

[Wolverine]

Do you have any sources for this? I thought it had been hypothesized that loss of the field could indeed occur during the shift, as well as an ineffective field for years even millennia during the shift.

I only recall reading the opposite.

Reversals take a few thousand years to complete, and during that time--contrary to popular belief--the magnetic field does not vanish. "It just gets more complicated," says Glatzmaier. Magnetic lines of force near Earth's surface become twisted and tangled, and magnetic poles pop up in unaccustomed places. A south magnetic pole might emerge over Africa, for instance, or a north pole over Tahiti. Weird. But it's still a planetary magnetic field, and it still protects us from space radiation and solar storms.

I once had multiple bookmarks addressing the topic but this is all I can currently locate.

 

[Hellbound]

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.

It'd sterilize the surface, sure. I just think it's have to be quite a bit bigger to get everything that's living much deeper, both in the ocean bottoms and in the rocks, because htese are microrganisms that are pretty well protected (by depth of earth or depth of water) and that don't rely on the sun for energy (dust coulds and such blocking sunlight would have little to no effect for them).

Chemolithoautotrophic bacteria have been found at depths of 3km below the surface. even with the surface sterilized, eventually some of those from that depth will be pushed up (by geological activity and such) and start evolution again.

 

[aggle-rithm]

It'd sterilize the surface, sure. I just think it's have to be quite a bit bigger to get everything that's living much deeper, both in the ocean bottoms and in the rocks, because htese are microrganisms that are pretty well protected (by depth of earth or depth of water) and that don't rely on the sun for energy (dust coulds and such blocking sunlight would have little to no effect for them).

Chemolithoautotrophic bacteria have been found at depths of 3km below the surface. even with the surface sterilized, eventually some of those from that depth will be pushed up (by geological activity and such) and start evolution again.

I've heard a theory that the ancestors of these bacteria may have survived an extinction event where an asteroid impact melted the entire surface of the globe. If true, then we all descended from this bacteria.

 

[dasmiller]

I've heard a theory that the ancestors of these bacteria may have survived an extinction event where an asteroid impact melted the entire surface of the globe. If true, then we all descended from this bacteria.

And, you know, we never call. I feel kinda bad about that now. I mean, would it kill us to pick up the phone once in a while, "Hi, how are you doing?" Maybe take the bacteria out to lunch, 'cause you know it doesn't get out much. After all, how many nice restaurants can there be, 3 km underground?

Maybe tomorrow, I'll try to remember.

 

[shadron]

It'd sterilize the surface, sure. I just think it's have to be quite a bit bigger to get everything that's living much deeper, both in the ocean bottoms and in the rocks, because htese are microrganisms that are pretty well protected (by depth of earth or depth of water) and that don't rely on the sun for energy (dust coulds and such blocking sunlight would have little to no effect for them).

Chemolithoautotrophic bacteria have been found at depths of 3km below the surface. even with the surface sterilized, eventually some of those from that depth will be pushed up (by geological activity and such) and start evolution again.

There are indications that life on Earth may have developed before the Late Heavy Bombardment^WP (3.82 to 3.95 bya); in fact there are indications that photosynthetic bacteria started converting CO2 to O2 right on the heels of the end of the LHB. It is believed that the LHB probably liquified the entire crust, though these life findings are challenging that assumption; obviously life would have had to be extreme in the limits to have lived through 1000+ degrees F through the entire crust.

 

[Cuddles]

Such CME did not yet happened.

How do you know?

Chances are it won't happen in the future.

That's not how reality works. Just because something hasn't happened yet doesn't mean it will never happen. More to the point, just because we don't know if something has happened or not certainly does not mean it will never happen.

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.

Doesn't matter. a big enough impact could easily kill everything on the Earth's crust, or even destroy the Earth entirely. Obviously that's even less likely than a pansy little mass extinction inducing one, but there are certainly a few bodies capable of doing it if they somehow got pointed in the wrong direction.

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.

Yeah, this is really the big concern with CMEs. Mass extinctions are potentially possible, but really aren't really something to worry about. Taking out power grids and satellites is not just a potential problem, but something that we've already seen happen plenty of times. So far it's mostly been relatively minor stuff such as a few satellites and half of Canada, but something on the scale of 1859 would be likely to cause some pretty major problems. I very much doubt we'd be looking at the collapse of society as some of the more doomongering types like to claim, but even just loss of power for a few countries for a few days would be pretty serious.

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.

Not necessarily. The chance of any given CME actually hitting the Earth isn't particularly high, so if only one or two happen to have hit us since complex life has existed that could just mean one big enough only happens every few hundred million years. Rare, but not entirely implausible.

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.

Yeah, a big problem with CMEs, GRBs and such as hypotheses for mass extinctions is the lack of any evidence left over. Essentially all you have is a bunch of radiation messing with the upper atmosphere, and that doesn't leave an awful lot of evidence behind for us to look at. The theory saying that they could be responsible for mass extinctions is pretty solid, but whether they actually have been is a much harder question to answer.

 

[Hellbound]

Doesn't matter. a big enough impact could easily kill everything on the Earth's crust, or even destroy the Earth entirely. Obviously that's even less likely than a pansy little mass extinction inducing one, but there are certainly a few bodies capable of doing it if they somehow got pointed in the wrong direction.

Actually, that was kinda my point. I don't think you'd wipe out all life unless you pretty well destroyed the planet. I wasn't arguing the possibility, just the size of impactor required

 

[Dr.Sid]

How do I know there was no CME which wiped life on Earth ? Because there is a life on Earth.

 

[Cuddles]

How do I know there was no CME which wiped life on Earth ? Because there is a life on Earth.

There are four big problems here. Firstly, we are mostly not talking about wiping out all life on Earth. There have certainly been plenty of mass extinctions, and you have no idea if any of them may have been due to CMEs.

Secondly, see if you can find the problem with this statement - "There is milk in my fridge. Therefore I did not drink the milk that was in my fridge last week.".

Thirdly, you apparently decided to ignore the rest of my reply to you - the possibility of something happening in the future is not necessarily dependent on whether it happened in the past. If it is possible for the Sun to put out a CME that could wipe out all life on Earth, the fact that it has not yet done so is irrelevant.

Finally, you also ignored the rest of my post, in particular the part where I point out that the Earth is not a sphere completely enclosing the Sun, and it is therefore entirely possible (indeed rather more likely than not) for a CME to miss the Earth entirely. That a CME capable of wiping out life on Earth has not actually hit the Earth is not evidence that such a CME has not happened at all.

 

[CORed]

I wouldn't hesitate to bet my life savings that a solar flare will never wipe out life on Earth.

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

I'll take that bet, if you can tell me how to collect if I win.

 

[Dr.Sid]

There are four big problems here. Firstly, we are mostly not talking about wiping out all life on Earth. There have certainly been plenty of mass extinctions, and you have no idea if any of them may have been due to CMEs.

Secondly, see if you can find the problem with this statement - "There is milk in my fridge. Therefore I did not drink the milk that was in my fridge last week.".

Thirdly, you apparently decided to ignore the rest of my reply to you - the possibility of something happening in the future is not necessarily dependent on whether it happened in the past. If it is possible for the Sun to put out a CME that could wipe out all life on Earth, the fact that it has not yet done so is irrelevant.

Finally, you also ignored the rest of my post, in particular the part where I point out that the Earth is not a sphere completely enclosing the Sun, and it is therefore entirely possible (indeed rather more likely than not) for a CME to miss the Earth entirely. That a CME capable of wiping out life on Earth has not actually hit the Earth is not evidence that such a CME has not happened at all.

Actually the original question was 'wiping Earth' .. so not only life. And yes, there could be some extinctions, but I certainly would not call such event wiping Earth, or wiping live on Earth.

Yes, past experience is irrelevant. It actually seemed like funny statement to me, never mind.

I did not comment on the other parts as I totally agree with them, there is no need to comment.

 

[Hindmost]

....snip...


Yeah, this is really the big concern with CMEs. Mass extinctions are potentially possible, but really aren't really something to worry about. Taking out power grids and satellites is not just a potential problem, but something that we've already seen happen plenty of times. So far it's mostly been relatively minor stuff such as a few satellites and half of Canada, but something on the scale of 1859 would be likely to cause some pretty major problems. I very much doubt we'd be looking at the collapse of society as some of the more doomongering types like to claim, but even just loss of power for a few countries for a few days would be pretty serious.

....snip...

Hmm...inline with what I think about this. I am concerned that a direct shot that could take out a fair number of large transformers or generators and crash the grid over a wide area. Since transformers and generators are not easy to replace quickly, there could be some problems with getting the grid back up in a timely manner. And there is always the unknow effects. I would really like to be able to quantify the whole thing, but it is difficult to test...

glenn

 

[volcano]

Actually, no. Lava is not magnetic. The liquid that causes the Earth's field is the outer core, of molten iron.

[puts on pedantic hat] Depends what you mean by magnetic. Molten lava (I'm assuming we're talking about basalt here) is mostly paramagnetic-- little bits of iron line up with the Earth's magnetic field and record the field direction at the time the lava cooled*, so technically the lava does hold on to a bit of remnant magnetization. And basalt contains the mineral magnetite, which is ferro/ferrimagnetic. [takes off pedantic hat]

I've been thinking a bit about this (the magnetization of lava) since shadron's comment was first posted. I wonder: if Earth's outer core stopped rotating entirely, how much of a residual magnetic field would exist solely from the remnant magnetism in lava flows? Perhaps they'd mostly cancel out since the orientation varies depending on the age of the flow (i.e., depending on where Earth's magnetic north was when the flow erupted). But locally, at least, I suspect they could induce a very small magnetic field.

*This is one of the main ways we know 1) Plate tectonics occurs and 2) How often Earth's magnetic field switches polarity.

 

[ben m]

A random back-of-the-envelope calculation.

The electric generating capacity of the US (10^12 W) represents about 10^10 amperes at 120V. ("So what? You can transform it to more or less." I agree, I just want a number to start with; bear with me.) If you took 10% of that (10^9 amperes) and put it through a bank of cables wrapped once around the Earth's equator, the resulting dipole (10^23 A.m^2) would be about as strong as the Earth's natural geodynamo.

So you can imagine that a future society---presumably one which has invented room-temperature superconductors---could do without the geodynamo and maintain the Earth's field artificially.

 

[dasmiller]

A random back-of-the-envelope calculation.

The electric generating capacity of the US (10^12 W) represents about 10^10 amperes at 120V. ("So what? You can transform it to more or less." I agree, I just want a number to start with; bear with me.) If you took 10% of that (10^9 amperes) and put it through a bank of cables wrapped once around the Earth's equator, the resulting dipole (10^23 A.m^2) would be about as strong as the Earth's natural geodynamo.

So you can imagine that a future society---presumably one which has invented room-temperature superconductors---could do without the geodynamo and maintain the Earth's field artificially.

You know, in all the SF I've read (and in my younger days, that was a lot), I don't think I've ever heard of anyone suggest such a thing.

And if it could be done on Earth, it could be done on some other planet if needed . . .

 

[Skeptic Ginger]

[puts on pedantic hat] Depends what you mean by magnetic. Molten lava (I'm assuming we're talking about basalt here) is mostly paramagnetic-- little bits of iron line up with the Earth's magnetic field and record the field direction at the time the lava cooled*, so technically the lava does hold on to a bit of remnant magnetization. And basalt contains the mineral magnetite, which is ferro/ferrimagnetic. [takes off pedantic hat]

I've been thinking a bit about this (the magnetization of lava) since shadron's comment was first posted. I wonder: if Earth's outer core stopped rotating entirely, how much of a residual magnetic field would exist solely from the remnant magnetism in lava flows? Perhaps they'd mostly cancel out since the orientation varies depending on the age of the flow (i.e., depending on where Earth's magnetic north was when the flow erupted). But locally, at least, I suspect they could induce a very small magnetic field.

*This is one of the main ways we know 1) Plate tectonics occurs and 2) How often Earth's magnetic field switches polarity.

I have dozens of lava rocks from all over the county. Some of them actually have a fair amount of iron in them and are attracted by a magnet.

 

[LandR]

100 million hydrogen bombs.

Yahoos take on the pending solar flares of doom and catastrophe:

Melbourne, Aug 26 (ANI): Astronomers are predicting that a massive solar storm, much bigger in potential than the one that caused spectacular light shows on Earth earlier this month, is to strike our planet in 2012 with a force of 100 million hydrogen bombs.

http://in.news.yahoo.com/139/20100826/981/tsc-massive-solar-storm-to-hit-earth-in_1.html

*Sigh*

They might, technically, be correct with 100 million hydrogen bombs but a little context would be nice. Using the phrase '100 million hydrogen bombs' conjures up certain imagery which I feel is only designed to scare people, that and the 2012 'disaster' date. Got to get 2012 in there..

 

[Lensman]

What a great idea for a science fiction monster movie! I wonder if it's been done yet.

IMDB is your friend

(It's loosely based on a short story by Larry Niven.)