Scientists ‘Iron Out’ Phenomenon That Sustains Magnetic Field Of Earth

Without Earth’s magnetic field, life on the planet might not exist.

For 3.4 billion years, this magnetic field has prevented Earth from becoming extremely vulnerable to high-energy particles called cosmic radiation.

Scientists know that what generates the protective magnetic field is the low heat conduction of liquid iron in the planet’s outer core. This phenomenon is known as “geodynamo.”

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CrazyNeutrino said:

Without Earth’s magnetic field, life on the planet might not exist.

Meh … life begain in the oceans anyway, and 10 metres of ocean would provide as much shielding as the magnetic field does. Things might be different but there’s no good reason to say life would not have arisen.

dv said:

CrazyNeutrino said:

Without Earth’s magnetic field, life on the planet might not exist.

Meh … life begain in the oceans anyway, and 10 metres of ocean would provide as much shielding as the magnetic field does. Things might be different but there’s no good reason to say life would not have arisen.

One of the things that would be different would be that the Earth’s atmosphere would either be much thinner or have been blown away comletely by solar radiation. In that case, life might have arisen, but died out long ago.

btm said:

dv said:

CrazyNeutrino said:

Without Earth’s magnetic field, life on the planet might not exist.

Meh … life begain in the oceans anyway, and 10 metres of ocean would provide as much shielding as the magnetic field does. Things might be different but there’s no good reason to say life would not have arisen.

One of the things that would be different would be that the Earth’s atmosphere would either be much thinner or have been blown away comletely by solar radiation. In that case, life might have arisen, but died out long ago.

Why? You don’t need an atmosphere for life.

dv said:

btm said:

dv said:

Meh … life begain in the oceans anyway, and 10 metres of ocean would provide as much shielding as the magnetic field does. Things might be different but there’s no good reason to say life would not have arisen.

One of the things that would be different would be that the Earth’s atmosphere would either be much thinner or have been blown away comletely by solar radiation. In that case, life might have arisen, but died out long ago.

Why? You don’t need an atmosphere for life.

Surely without an atmosphere you quite quickly run out of ocean?

dv said:

btm said:

dv said:

Meh … life begain in the oceans anyway, and 10 metres of ocean would provide as much shielding as the magnetic field does. Things might be different but there’s no good reason to say life would not have arisen.

One of the things that would be different would be that the Earth’s atmosphere would either be much thinner or have been blown away comletely by solar radiation. In that case, life might have arisen, but died out long ago.

Why? You don’t need an atmosphere for life.

True. I was thinking of life as it is now. I sit properly corrected.

sibeen said:

dv said:

btm said:

One of the things that would be different would be that the Earth’s atmosphere would either be much thinner or have been blown away comletely by solar radiation. In that case, life might have arisen, but died out long ago.

Why? You don’t need an atmosphere for life.

Surely without an atmosphere you quite quickly run out of ocean?

We’re in a pretty deep well here. There’ll be some kind of atmosphere as the liquid and gas phases reach equilibrium.

sibeen said:

dv said:

btm said:

One of the things that would be different would be that the Earth’s atmosphere would either be much thinner or have been blown away comletely by solar radiation. In that case, life might have arisen, but died out long ago.

Why? You don’t need an atmosphere for life.

Surely without an atmosphere you quite quickly run out of ocean?

Would oceans freeze without atmosphere?

CrazyNeutrino said:

sibeen said:

dv said:

Why? You don’t need an atmosphere for life.

Surely without an atmosphere you quite quickly run out of ocean?

Would oceans freeze without atmosphere?

As the atmosphere thinned, the oceans would evaporate, but the latent energy due to the phase change would take heat from the water that hadn’t yet evaporated, and freeze some of it. Over time, though, the sun would melt it again, and it would eventually all evaporate.

CrazyNeutrino said:

sibeen said:

dv said:

Why? You don’t need an atmosphere for life.

Surely without an atmosphere you quite quickly run out of ocean?

Would oceans freeze without atmosphere?

No.

CrazyNeutrino said:

sibeen said:

dv said:

Why? You don’t need an atmosphere for life.

Surely without an atmosphere you quite quickly run out of ocean?

Would oceans freeze without atmosphere?

If you had oceans without an atmosphere, you’d instantly get an atmosphere (of water vapour) due to evaporation, and this atmosphere would increase over time. The balance between liquid, gas and solid would depend on radiation levels. Here on earth, the solar radiation and geopotential well are such that water vapour would be at a low enough temperature to prevent rapid loss to space (at higher temperatures, you’ll lose more quickly). With cosmic rays of course the water will be broken up eventually.

without life, what would be the composition of the atmosphere?

party_pants said:

without life, what would be the composition of the atmosphere?

Well the early atmosphere had carbon dioxide, argon, methane, hydrogen. Nitrogen increased over time partly through exsolution and partly through bombardments.

Carbon dioxide, argon, and nitrogen are pretty stable. Methane and hydrogen will not last in an oxygenated atmosphere so it makes sense that, in our oxygenated world, they were depleted.

So it would still be mainly that stuff, CO2, Ar, CH4, N2, I suppose, but we’d have lost the hydrogen to space.

party_pants said:

without life, what would be the composition of the atmosphere?

I’ve got a piece of quartz crystal with a small cavity in it, with water and a bubble of air in the cavity. I don’t know how old it is, but I’ve been thinking of analysing it to (a) find its age, and (b) the composition of the gas bubble (and what’s in the water). I haven’t done it yet, but it would give me an idea of what the atmosphere was when the quartz crystallised.

• I’ve got a piece of quartz crystal with a small cavity in it, with water and a bubble of air in the cavity. I don’t know how old it is, but I’ve been thinking of analysing it to (a) find its age, and (b) the composition of the gas bubble (and what’s in the water). I haven’t done it yet, but it would give me an idea of what the atmosphere was when the quartz crystallised.

By which method would you extract and analyse this gas?

furious said:

• I’ve got a piece of quartz crystal with a small cavity in it, with water and a bubble of air in the cavity. I don’t know how old it is, but I’ve been thinking of analysing it to (a) find its age, and (b) the composition of the gas bubble (and what’s in the water). I haven’t done it yet, but it would give me an idea of what the atmosphere was when the quartz crystallised.

By which method would you extract and analyse this gas?

I wouldn’t extract it; I’d use atomic absorption spectroscopy. I want to keep the stone in its present form, so extracting the liquid and gas would be out of the question.

• I wouldn’t extract it; I’d use atomic absorption spectroscopy.

AAS requires destruction of items of interest in flame…

furious said:

• I wouldn’t extract it; I’d use atomic absorption spectroscopy.

AAS requires destruction of items of interest in flame…

It requires atomisation of the sample, which does usually mean the sample is destroyed. I’ll have to think some more about it, then.

• It requires atomisation of the sample, which does usually mean the sample is destroyed. I’ll have to think some more about it, then.

Lasers?

furious said:

• It requires atomisation of the sample, which does usually mean the sample is destroyed. I’ll have to think some more about it, then.

Lasers?

Yeah, laser absorption spectrometry is looking promising. I’ve got an AAS, but not a LAS, though I could possibly use my old university’s labs.

• Yeah, laser absorption spectrometry is looking promising. I’ve got an AAS, but not a LAS, though I could possibly use my old university’s labs.

Not many people have an AAS in the shed…

btm’s not many people

• btm’s not many people

Indeed…

furious said:

• Yeah, laser absorption spectrometry is looking promising. I’ve got an AAS, but not a LAS, though I could possibly use my old university’s labs.

Not many people have an AAS in the shed…

True. Not many people have got a piece of quartz crystal with a water-and-gas-filled cavity in it, either.

• True. Not many people have got a piece of quartz crystal with a water-and-gas-filled cavity in it, either.

touché…

there is water in every opal.

dv said:

CrazyNeutrino said:

Without Earth’s magnetic field, life on the planet might not exist.

Meh … life begain in the oceans anyway, and 10 metres of ocean would provide as much shielding as the magnetic field does. Things might be different but there’s no good reason to say life would not have arisen.

As with all science reporting, any sentence containing the word “might” should be ignored.

I agree. In addition, the origins of life require energy input (other than just heat alone) and it has been claimed that cosmic rays from the young Sun, being more plentiful than lightning, could have provided the energy needed to activate the molecules so they could polymerise. in other words, without Earth’s magnetic field, life could have developed sooner.

> experts have yet to understand how the geodynamo was first created and sustained all throughout history.

Good to see confirmation of that.

> a puzzle raised in 2012 called “geodynamo paradox,” iron’s thermal conductivity in the core was at 150 watts per meter per kelvin, but such a high amount would prevent the geodynamo from even starting up. If a lot of heat were transferred through conduction, not much energy would be left to power convection and the geodynamo.
This amount would also mean that the geodynamo effect was only supported rather recently in Earth’s history — only about a billion years or so. However, calculations (do they mean observations?) can trace back the phenomenon to at least 3.4 billion years. This was the geodynamo paradox.

That’s very interesting, I hadn’t thought of that. A few things come to mind. One is that the impact that formed the Moon would have given convection in the core a kick start. A second is that radioactivity was stronger for the early Earth so convection ought to have been stronger then than now, but only if the inner core wasn’t too much smaller. A third is that the phase change on the outer surface of the inner core releases latent heat that can drive convection in the same way that condensation of water drives convection in clouds.

> researchers found that the ability of iron to transmit heat were not at par with previous estimates of thermal conductivity in the core. It was actually between 18 and 44 watts per meter per kelvin.
This suggests that the energy needed to sustain the geodynamo has been present since very early in Earth’s history, researchers concluded. Our results strongly contradict the theoretical calculations

Good work! Why have the theoretical calculations failed so spectacularly?

btm said:

party_pants said:

without life, what would be the composition of the atmosphere?

I’ve got a piece of quartz crystal with a small cavity in it, with water and a bubble of air in the cavity. I don’t know how old it is, but I’ve been thinking of analysing it to (a) find its age, and (b) the composition of the gas bubble (and what’s in the water). I haven’t done it yet, but it would give me an idea of what the atmosphere was when the quartz crystallised.

Analysing fluid inclusions is a common (generally academic) technique in geology. It gives information about the fluid the quartz crystallised from. (Pressure, temperature and salinity.) I can’t see how one could get info about atmospheric composition and age from a fluid inclusion.

mollwollfumble said:

As with all science reporting, any sentence containing the word “might” should be ignored.

On the other hand I would say that any sentence not containing the word “might” should be ignored, or at least treated with extreme scepticism.

mollwollfumble said:

Good work! Why have the theoretical calculations failed so spectacularly?

Presumably because of:
1) The lack of independent observations to check them against.
2) The tendency to treat any calculation made by a person of sufficient reputation as not requiring checking, which I like to call the Galileo Effect.

The Rev Dodgson said:

Presumably because of:
1) The lack of independent observations to check them against.
2) The tendency to treat any calculation made by a person of sufficient reputation as not requiring checking, which I like to call the Galileo Effect.

Hear hear.

The Rev Dodgson said:

2) The tendency to treat any calculation made by a person of sufficient reputation as not requiring checking, which I like to call the Galileo Effect.

Why Galileo? As opposed to, say, Galen, Aristotle, Ptolemy or Marco Polo.

mollwollfumble said:

The Rev Dodgson said:

2) The tendency to treat any calculation made by a person of sufficient reputation as not requiring checking, which I like to call the Galileo Effect.

Why Galileo? As opposed to, say, Galen, Aristotle, Ptolemy or Marco Polo.

Because his erroneous theory, that was accepted for 200+ years, dealt with beams, and as everyone knows, the beam is the most important invention in the history of civilisation :)

party_pants said:

without life, what would be the composition of the atmosphere?

Well there wouldn’t be any fart gas.

bob(from black rock) said:

party_pants said:

without life, what would be the composition of the atmosphere?

Well there wouldn’t be any fart gas.

Your Body Is Surrounded by Clouds of Skin and Fart Bacteria