Earth's magnetic reversals, and risks..

[TallDave]

Cosmic rays don't penetrate far enough to matter. It's not like you get lethal dosages of radiation at the poles.

http://en.wikipedia.org/wiki/Cosmic_rays

I doubt the difference over a lifetime (without the Earth's magnetic field) would amount to a chest-xray. We'd just get some extra C-14.

[clonan]

We have been successfully in doing what? Surviving?

Just for the love of making an example, ants and mosquitos have been on this planet from much before than our race, and will be probably on this planet much after our departure.

Thats easy...The true measure of a species success is the number of BREEDING members of the species. We have almost 7 billion breeding members.

There is no multi-cellular animal that has as many breeding members as Homo sapiens and the species that directly predate on us (like head-lice).

If you look at Ants, then each colony has one breeding member. Mosquitoes do a little better, but not much.

Head-lice are probably about even with us, maybe a little higher.

I doubt that any species ever had or will ever have a higher number of breeding members than humans.

[chrismb]

We have been sucesfull in doing what? Surviving?

Numerical survival is irrelevant. You are trivialising life itself. Animals are not "alive" that are not sentient. "Life" is a sentient act.

We have become civilised and we have tamed nature itself. We have created ourselves alive. Our intellect has given birth to something this planet, perhaps the universe, has never witnessed.

"Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do. Let us go down, and there confound their language, that they may not understand one another's speech." - Even God himself fears our intellect!!!

We [many of us ] have made gains to break free from the shakles of the biological vehicles that carry around our brains and are dedicated to nutrition and faunication. Now our consciousness exceeds that which our brains evolved to do. We have begun to unpick the limitations of biology and of physics itself! We destroy matter itself and use that destruction as energy to drive our world, the world WE have created.

And you question our success?

[CaptainBeowulf]

So are you saying we will ultimately upload our minds out of these biological vehicles and become Kurzwelian AI singularities with godlike powers ourselves?!

On the point of destructive radiation getting through the atmosphere during a pole flip, if it's not masses of cosmic rays that can penetrate walls, just increased UV or whatever, then our scientific instruments and theories will show it coming. We'll just stay indoors during the day and go out at night. Or wear hoods and cloaks. Maybe people in less educated regions of the world won't believe it and will die... but it really shouldn't make much difference to people like us.

[chrismb]

So are you saying we will ultimately upload our minds out of these biological vehicles and become Kurzwelian AI singularities with godlike powers ourselves?!

I don't see any reason why a sentient intellect resident in a manufactured machine would take on god like powers (unless there are some aspects of quantum information-entropy behaviour we do not understand, viz. telekinetic effects by the manipulation of information alone). No, I think that bit will remain science fiction. But could an intellect be transferred, or created within, a manufactured device? If mankind can stay alive long enough - and also maintains its technological infrastructures in the face of dimwitted disinterest - then, yes I am confident it will be so.

On the point of destructive radiation getting through the atmosphere during a pole flip, if it's not masses of cosmic rays that can penetrate walls, just increased UV or whatever, then our scientific instruments and theories will show it coming.

Well, that is the bottom line of my question. Will it be so benign? I mean, the point above about standing on the poles don't kill you, but there again standing at a pole the Solar wind isn't on a vetor heading straight down the field lines (so as to be minimally affected) whereas once the magnetic field lines are suspended during reversals then what is to stop solar particles penetrating the atmosphere? Maybe it'll just compromise the ozone layer and, as you say, just keeping out of the sun for a few months will mitigate any effects. I dunno, maybe full exposure to the solar wind will do worse. It was a question - and I don't have the answer.

[csgt428]

Surely we have some idea of the time frame for pole reversals from sea floor magnetic alignment of newly created crust data obtained from past reversals? New crust is being created constantly where crustal plates are spreading apart. The magnetic field lines up magma's polar molecules to the existing N/S orientation while still fluid. Once it hardens there is a record. Isn't this how pole reversals were discovered in the first place?

[chrismb]

Surely we have some idea of the time frame for pole reversals from sea floor magnetic alignment of newly created crust data obtained from past reversals?

Yes we do. It is long overdue.

[Giorgio]

We have been successfully in doing what? Surviving?

Just for the love of making an example, ants and mosquitos have been on this planet from much before than our race, and will be probably on this planet much after our departure.

Thats easy...The true measure of a species success is the number of BREEDING members of the species. We have almost 7 billion breeding members.

There is no multi-cellular animal that has as many breeding members as Homo sapiens and the species that directly predate on us (like head-lice).

I have to disagree on this.
There is plenty of Multi-Cellular life form of all dimensions whose breeding number surpasses the one of our race even by several order of magnitudes.
From sub millimeter (dust acari as example) to centimeter (cockroaches), to sub meter (rabbits anyone?), to meter (sheeps and cows).

If your point is that none of them is a direct predator of our race, this is also trivial, as being at the top of the chain does not imply that a race is successful or can keep its position for an indefinite period. See what happened to the dinosaurs as example.

[Giorgio]

We have been sucesfull in doing what? Surviving?

Numerical survival is irrelevant. You are trivialising life itself. Animals are not "alive" that are not sentient. "Life" is a sentient act.

The main difference between humans and the rest of the animals of this world is that humans are driven by "greed".
Greed for power, for knowledge, for reproduction, for personal interests, this is the engine and the push that allowed us to evolve in such a short time.
Read back the last 10000 years of our history and prove me wrong.

The side effect of this "greed"? We are the only "animals" on this planet that kill members of their own specie in the name of someone else (be it a real or an abstract entity) or just for the fun of it.
Are we really better that the rest of the animals in this planet?

We have become civilised and we have tamed nature itself. We have created ourselves alive. Our intellect has given birth to something this planet, perhaps the universe, has never witnessed.

Bring your feet back to earth.
Less than 100 years ago most of our race was still living in mud. Just because our living conditions have evolved so much in the last century it does not mean that we know everything.
We don't even understand yet some of the basic aspects of our world (like gravity and mass) and you elevate our intellect to the top of the universe?

The Human race has yet to prove to have the right to call itself "intelligent" in respect to this planet, let alone to the universe.

We destroy matter itself and use that destruction as energy to drive our world, the world WE have created.

We have not "created" the world, we are born on this rock.

And you question our success?

Until now we have only been successful in praising ourselves, but this is not something that the universe cares about.

[taniwha]

The dinosaurs were done in by external events (asteroid). Their demise is rather irrelevant.

Successful is as simple as "can breed fast enough for its population to grow".

Back to cosmic rays: first, it seems I was wrong about "solar cosmic rays". I have to agree, it's a horrible name.

As for the radiation effects, in Australia, cosmic rays account for 0.3mSv/yr (out of 2.3) of normal, everyday exposure. The recommended limit is 5mSv/yr for children (50mSv/yr for adults).

The ground-level cosmic ray flux would have to increase nine fold for radiation levels in Australia to hit the limits for children. I'm pretty certain Earth's magnetic field doesn't make that much difference (I could be wrong, of course).

Also note that due to the magnetic field, the flux would increase as you approached the poles. If (when?) the field collapses, the overall flux probably won't increase all that much, but it will be more even from poles to equator.

The solar wind (the source of the "solar cosmic rays") comes from the sun, so indeed there's no head-on stream with the poles, but the magnetic field does tend to funnel a large portion of the wind that hits Earth to the poles. Also, because the solar wind comes from the sun, this part of cosmic radiation will have a day/night cycle.

Galactic cosmic rays come from every direction.

The biggest effect I predict during a field reversal is wicked aurora .

[taniwha]

In addition, the last reversal was about 780000 years ago: long after our ancestors evolved. Also, the flip seems to take 100s-1000s of years. (info from wikipedia.

I think asteroids are a much bigger worry.

[Giorgio]

The dinosaurs were done in by external events (asteroid). Their demise is rather irrelevant.

Scientific hypotesis range from asteroid to vulcanic activity. For what I know up to today there is no relevant proof for one or the other.

Successful is as simple as "can breed fast enough for its population to grow".

We can also take that as a definition, but than the majority of earth species are successful.

[taniwha]

The dinosaurs were done in by external events (asteroid). Their demise is rather irrelevant.

Scientific hypotesis range from asteroid to vulcanic activity. For what I know up to today there is no relevant proof for one or the other.

I read recently that it actually was proven (crater found, even). However, that doesn't matter: it was still external events that did in the dinosaurs. Until then, they were just as successful as any other creature.

Successful is as simple as "can breed fast enough for its population to grow".

We can also take that as a definition, but than the majority of earth species are successful.

That's my point.

This talk of which species is the most successful is nothing more than hot air (less, actually: hot air is useful).

[Giorgio]

The dinosaurs were done in by external events (asteroid). Their demise is rather irrelevant.

Scientific hypotesis range from asteroid to vulcanic activity. For what I know up to today there is no relevant proof for one or the other.

I read recently that it actually was proven (crater found, even).

Have any link?
I am deeply interested in it.

Successful is as simple as "can breed fast enough for its population to grow".

We can also take that as a definition, but than the majority of earth species are successful.

That's my point.

This talk of which species is the most successful is nothing more than hot air (less, actually: hot air is useful).

And that's my point too. I guess we have the same point after all.

[taniwha]

Well, not having the link handy (dig through the general forum archives, it's in one of the AGW threads), I tried some googling and found this. It seems it may not have been one killer asteroid, but two, along with volcanoes spurred on by the second.