Volcanic Eruptions

[lebyasarabia]

many volcanoes around the globe have been erupting.. What's the indication/s of these eruptions?

[Watson]

They have been erupting and indication is they will continue to do so. What is your question? You'll need to be a bit more specific about what you are asking. Welcome.

[Dave_Oblad]

Hello lebyasarabia,

Welcome to the Forums.

Why do folks select such complicated Avatar names?

What's the indication/s of these eruptions?

I think the primary indication of an Eruption is all the Lava, Rocks and Smoke that bellows out of the volcano ;^P

Regards,
Dave :^)

[lebyasarabia]

thanks for immediate response.

to be more specific is, do they have something to do with climate change or global warming, wherein as what i"ve read, volcanic eruptions cooled down the earth's temperature?

[Watson]

I doubt it is climate change/warming that is causing it. More likely fracking and other mining activities, if man made disturbances and quakes. More likely it is just the natural evolution of a molten planet with shifting plates. But yes I think there is historical evidence the eruptive plumbs could/would block out the sun and have a cooling effect on the earth's temperature.

[Dave_Oblad]

Hi again lebyasarabia,

Volcanoes are produced by shifts in the Earths Mantle. These shifts are generally too deep to be caused by surface features such as weather. The heat from the atomic electro-magnetic Engine at the Earths core, along with the Sun & Moon creating plate tectonic stresses and even the rotation of the Earth are related to the cause of Mantle shifts and cracks leading to volcanic actions. Volcanoes can easily shift surface weather patterns and affect Global Warming etc.. but I really doubt the reverse is true or of much consequence.

https://en.wikipedia.org/wiki/Volcano

Regards,
Dave :^)

[Eclogite]

Hi again lebyasarabia,

Volcanoes are produced by shifts in the Earths Mantle. These shifts are generally too deep to be caused by surface features such as weather. The heat from the atomic electro-magnetic Engine at the Earths core, along with the Sun & Moon creating plate tectonic stresses and even the rotation of the Earth are related to the cause of Mantle shifts and cracks leading to volcanic actions. Volcanoes can easily shift surface weather patterns and affect Global Warming etc.. but I really doubt the reverse is true or of much consequence.

https://en.wikipedia.org/wiki/Volcano

Regards,
Dave :^)

Dave, I never engage in your discussions of physics, but now you are on ground familiar to me I really must declare - much of that post isn't even wrong.

Volcanoes are produced by shifts in the Earths Mantle.

In dozens of textbooks and hundreds of research articles I have never heard mantle plumes, or convection currents described as "shifts". If we are aiming to help educate the OP in vulcanology then it makes sense to use the terminology that is commonplace.

lebysarabia, vlocanoes arise primarily through three mechanisms:

1. Subduction of oceanic plates. The Ring of Fire around the Pacific is a classic example
2. Mantle plumes. The Hawaiian islands and Emperor Sea Mount chains are type examples for these.
3. Mid-Ocean Ridge. Submarine eruptions where the plates are splitting apart and allowing magma to reach the surface following partial melting within the mantle.

The heat from the atomic electro-magnetic Engine at the Earths core

There is no such thing. The magnetic field is sustained by a self-exciting dynamo in the molten outer core. The claim that there is a nuclear reactor in the inner core is promoted by a single researcher, Marvin Hendron. It is not remotely an accepted view.

It is the residual heat formation and decay of radioactive elements that generate and sustain mantle convection.

If you have recent sound, peer reviewed data supporting a significant effect on plate tectonics of lunar/solar tidal effects I would be delighted to see them.

I do agree with your conclusion that global warming would be unlikely to have any discernible effect on volcanic activity. I would also note that I do not believe there has been any increase in volcanic activity over the last decade, couple of decades, or century.

[uninfinite]

ecoglite,

As you are familiar with volcanoes, may I canvass your view on vulcanism as a source of (in theory) virtually limitless amounts of energy. Why is it not more widely used?

[Watson]

My guess is, the limitless amounts of energy is not easily accessible. And why go that extra mile, when the petroleum form it much closer. There is geo-thermal heating in my area. Imagine getting heat out of a frozen, snow covered landscape. But it requires a well or two, and hydro for pumps and compressors. That compared to my radiant gas stove heats my home even if the power goes off.
So the simple answer 'why' is, it isn't needed. I know that is not the answer you are looking for, and I hope Eclogite can give you more technical why not, or better yet, how this energy could be utilized.

Love the Pauli-ism.

[uninfinite]

Watson,

Thanks for the reply. Guessing is about all I can do too. I know a little, and have some relevant questions - but I would like to address them to someone more informed than I am. I'm guessing you're in Iceland - sat atop the mid-Atlantic ridge, and being torn apart at about the same rate as fingernails grow. I've looked into Iceland's geothermal energy sector, and it seems based upon hydrothermal venting - whereas I was thinking more about tapping directly into the magma. At 4 - 6,000 c it should be perfect for generating electricity - if that heat can be captured. It is better than petrol or gas because it's a carbon free source of energy - and it is not limited in quantity, such that it could be used to desalinate water for example - an energy intense process, but one desperately needed in some parts of the world.

[Watson]

I think whatever high tech drilling apparatus you would be using for this project it would become to soft to drill, long before you reach these temps. I think you could reach usable heat with a much shallower system. The 4-6,000 c may likely be to hot to be a usable form of energy, from a practical point. No doubt it is a cleaner form of energy and hopefully that will justify the cost and interest in moving in that direction.

[TheVat]

That sounds right, Watson. What little I know of geothermal, it is drawn from much shallower sources of heat where it is practical to drill and then circulate a fluid through a hot rock bed. This would be limited to spots where magma is closer to the surface and there is proximity to a continental power grid that can affordably distribute the generated power. In the U.S. that might along the West coast, around Yellowstone's supervolcano, etc.

[uninfinite]

I think whatever high tech drilling apparatus you would be using for this project it would become too soft to drill, long before you reach these temps. I think you could reach usable heat with a much shallower system. The 4-6,000 c may likely be to hot to be a usable form of energy, from a practical point. No doubt it is a cleaner form of energy and hopefully that will justify the cost and interest in moving in that direction.

I've considered two means to access that energy - both involving drilling, but not in order to reach liquid magma. The first concerns magma chambers, which can look something like this:




Drilling into the rock around the magma chamber, lining the hole with pipes as in oil drilling - and filling those pipes with a liquid would in effect create a heat conveyor - that could be used to generate electricity.


A similar technology could be employed at subduction zones. This is what they look like:



Drilling into the subducted plate - following the angel of its descent, would allow drilling into the mantle to a depth not possible drilling straight down through the crust and lithoshpere.

I imagine the amount of energy that could be harvested this way, at no environmental cost would be somewhere between large and massive - and if we could use the power of volcanic heat for large scale desalination and re-distribution of water, this could give us the ability to feed the world while protecting forest and marine ecosystems from over-exploitation.

[Watson]

Interesting that the thinner crust is in the ocean basins where you only have to drill about 10 miles down. Also good to have the self heeling cauterizing effect of sea water and molten rock.

[Watson]

I think this is were we need Eclogite's expertise on the matter.

[Dave_Oblad]

HI Eclogite,

You are correct of course. I used the word "shift" for the following reason:

Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates coming together. Volcanoes can also form where there is stretching and thinning of the crust's interior plates[clarify], e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism. Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth. Volcanoes are usually not created where two tectonic plates slide past one another.

So, in Bold highlight above, I redefined "diverging or converging" as a "shift" because "Shift" simply means to move from some place to another. In the Red highlighted portion they used the words "Slide Past", which in retrospect is also Shifting. Also, I confused Mantle with Plate. I apologize for my lack of clarity and confusion.

I, of course, defer to your expertise, as I only have a rudimentary understanding of volcanoes. I did have a strong instinct that a Volcano can be a cause of Global Warming but NOT that Global Warming can cause a Volcano.

Best Regards,
Dave :^)

[olivertamayao]

but why is it more frequent nowadays??

[lebyasarabia]

thank you for your response... but that's what's more bothering is that according to news, those volcanoes around the world have been erupting more frequent than before..

[Eclogite]

Sorry folks, I had missed some of the discussion and the implicit request for input.

First, lebyasarabia, it is not accurate to assess the frequency and severity of volcanic eruptions from news broadcasts. News coverage is determined by three things:

1. What else of note is happening in the world at the time. On a slow news day a small eruption will get air time.

2. Does the eruption have a direct and immediate effect on people. A tiny burp from Vesuvius and there will be wall to wall coverage, whereas a massive eruption in the Kurile Islands will go unremarked.

3. How close is the eruption to the target audience for the news broadcast.

The frequency of volcanic eruptions varies over time. You might wish to visit this site http://volcano.si.edu/search_eruption.cfm.

If you download the data into a spreadsheet program you can investigate yourself the extent of the variation. I think you will find there is no significant increase of late.


In regard to tapping into geothermal heat the commonest approach is to drill into an area of elevated temperature, circulate down water to be heated and then returned to surface to run steam turbines to generate electricity.

Approaching magma chambers more closely offers no particular advantages and would create numerous technical problems. Consequently we do not even need to go especially deep. The trick is to find somewhere with a high heat flow or residual heat from "recent" igneous activity.

Iceland has been mentioned already- it sits astride the mid-Atlantic ridge. Kenya currently has an active geothermal development program - the East African rift runs through it. I spent a few days driving up and down the sides of volcanoes in Java in relation to geothermal drilling - volcanoes that arise from subduction of the Indian Ocean plate below the South China Sea.

Uninfinite, I see no advantage* - and massive technical issues - in drilling down a subducting plate. We simply do not need to access magma like temperatures. Moreover, porous formations in the target zone are a benefit. The deeper we go the lower the porosity, so heading down that plate will be counterproductive.


*No advantage in geothermal terms. Great advantage in enhancing geological knowledge!

[uninfinite]

Uninfinite, I see no advantage* - and massive technical issues - in drilling down a subducting plate. We simply do not need to access magma like temperatures. Moreover, porous formations in the target zone are a benefit. The deeper we go the lower the porosity, so heading down that plate will be counterproductive.
*No advantage in geothermal terms. Great advantage in enhancing geological knowledge!

Ecoglite,

Thanks for your reply. I see magma and it seems to me, that all the energy we could ever need is right there beneath our feet - and instead we're burning coal and oil and causing climate change. If we simply do not need to access magma like temperatures - what do we need?; for this is the subject of my original question, which was:

''ecoglite,

As you are familiar with volcanoes, may I canvass your view on vulcanism as a source of (in theory) virtually limitless amounts of energy. Why is it not more widely used?''

I accept your apology for not replying earlier; but the manner in which you have replied - to criticize uneducated guesses ventured in your absence, seems to belie that apology. Further, what you do say:

'In regard to tapping into geothermal heat the commonest approach is to drill into an area of elevated temperature, circulate down water to be heated and then returned to surface to run steam turbines to generate electricity.'

...should be obvious to anyone who has a definition of the term 'geothermal energy' to hand. If this is the expertise we were waiting upon, colour me disappointed.

[Eclogite]

uninfinite,
you seemed to find two matters of concern in the tenor of my post. Let me deal with these first, before getting back on topic:

1. This is a science forum. You have displayed, in many other threads, a clear head, considerable knowledge, logical thinking and other attributes I associate with a trained scientist or engineer. Therefore I do not feel a need to "treat you gently". Therefore I dealt robustly with your suggestions since it never occurred to me you would not welcome that approach.

I did not call your idea silly. I said, very simply and very clearly, I could see no advantage in it. Frankly, I expected you to come back with some specifics challenging my dismissal of the notion, as a prelude to an interesting discussion.

So, I see nothing to apologise for in relation to my response. (At the risk of inflaming a minor disagreement I shall note if one does not wish to have uneducated guesses criticised then avoid making uneducated guesses.)

2. You chose to make an implicit insult when you said "If this is the expertise we were waiting upon, colour me disappointed." uninfinite, I suggest that you cannot have it both ways. Faced with "uneducated guesses" and a request for information I naturally pitched it at a very basic level. Your own post did not suggest you were someone who had "a definition of the term 'geothermal energy' to hand". I responded accordingly.

For the record, I am not an expert in geothermal exploration. I am an expert in aspects of the drilling process.


Back on Topic:

[quote="[url=http://www.sciencechatforum.com/viewtopic.php?p=299233#p299233]
"As you are familiar with volcanoes, may I canvass your view on vulcanism as a source of (in theory) virtually limitless amounts of energy. Why is it not more widely used?''

Two reasons:
1. Economic
2. Technical.

Economic
Oil, gas and coal have been much more suitable, less expensive, alternatives in most parts of the world. Concern with AGW and air pollution have partially overcome this.

Geothermal exploitation is inherently more expensive since its technology is less developed and therefore more costly than conventional energy sources.

Technical
All proposals I am aware of for geothermal work involved drilling boreholes. While it may seem apparent that the greatest benefits could be derived by getting close to the highest temperatures this raises huge difficulties.

1. Drilling fluids are adversely affected and become very much more expensive when designed to handle high temperatures. This does not only add to the direct cost of materials and expertise, but substantial rig time may be required to periodically circulate and condition the drilling fluid before resuming drilling. This would be to an extent beyond what would be required in conventional wells.

2. To maximise effective retrieval of thermal energy directional wells will often be favoured:
a) Directional sensor electronics cannot tolerate high temperatures.
b) Directional equipment requires seals. Traditional elastomer seals cannot tolerate high temperatures.
c) Although fixed cutter bits can replace roller cone bits, whose bearing systems are temperature sensitive, the geothermal industry has been uncomfortable with their cost. And in very high temperatures even thermally stable PDC will be compromised.

3. Completion equipment, for isolating zones; fracking equipment, for exposing more of the target zone; logging equipment, to characterise and correlate; all of these will either not function, function poorly, or be vastly more expensive than in conventional wells.

4. I also have reservations about the long term effects of cyclic temperatures upon drill pipe.

I can expand on any of these points if required and address any specific or general questions you may have.

[vivian maxine]

It seems we have two threads going on here but that's fine. They are "kissin' cuzzins". Lebyasarable, I'd not even noticed more volcanic eruptions but there surely have been a lot more earthquakes lately, haven't there? Maybe the two are connected.

Dave, I'd never dare in a million years question your knowledge of what causes volcanic eruptions. Actually, it makes sense. As the magma circulates back downward, it heats up again and, if those plates are soft, the heat can seek a release through them. So, I went back to my books and, sure enough, there it is just as you said. Now I can say "it's news to me" and really mean it. I mean I didn't know the connection between tectonic plate boundaries and erupting volcanoes. All right. Allow me just one point.

If the person at Missouri Geological Society informed me correctly - and I believe she did - there are no tectonic plate boundaries along our Mississippi. There is New Madrid fault which was formed by a different action but no plate boundary. Yet, there is a long-since-dead volcano in eastern Missouri. Of course those were other times, very long ago. No doubt the geological situation has changed substantially since that volcano showed its stuff.

By the way, an aside: New Madrid did a little dance a couple of weeks ago and only the locals noticed. We're told more tremors are coming. Planet Earth is very busy nowadays - global warming, volcanic activity, earthquakes, rising waters, and on and on. These threads are timely.

Uninfinite, your idea really got my attention. Heat the world from volcanoes! Tap into volcanoes for energy! Is that a good idea? Before getting really serious about the scary parts, may I mention fracking and its problems which do not even involve magma? Leaving that, can you tap into that heat without tapping into the magma itself? And what happens when that heat meets our cooler air? Of course there would be an effort to prevent the meeting of the two but can it be done? Volcanoes have uncontrollable tempers and they show off in tantrums on a regular basis.

More, can you get clean energy from that heat? My last question is the most important because I'm sure you didn't mean to say that volcanoes do not cause pollution, both air and ground. I think anyone who has been near an erupting volcano will object to that notion fast. That ash cloud is hazardous to your health. What was the volcanic eruption some centuries ago that blotted out the sunlight? Not Aetna. Another.

Don't give up your idea. Just keep answering all the challenges. Basically, can this be done safely? I've often wondered why the thermal heat from various hot springs have not been utilized to heat local homes and businesses. We read of some location deciding to try to tap in and then we get silence. What are they discoverng that makes them give up? Does that in any way relate to tapping into volcanoes?

I believe Eclogite addressed a lot of this quite well. I only ask the questions and await the answers.

[uninfinite]

Ecoglite,

I'm fine with having my ideas robustly criticized, if it is in relation to knowledge - the like of which you have displayed here. Your knowledge of drilling is very interesting - and does seem to constitute a realistic objection to ...what I would still maintain is basically a good and necessary idea.

Two reasons. First, approaching upon climate change, we need both clean energy, and massive amounts of energy - to desalinate water for irrigation - if we are to avoid drought, famine, war and mass migration. Further, as population increases we are placing unsupportable burdens upon forest and marine ecosystems that would be relieved by developing wastelands for agriculture - like desert land. And this is in addition to - the already numerous places in the world dependent upon desalination technology - often using large amounts of fossil fuel energy, at great expense and causing greenhouse gas emissions.

Second is mining, or more specifically - processing metalic ores. Deposits are not so much scarce, as less rich. As the richer, higher concentrated deposits are tapped out, its necessary to process more ore - to produce a given quantity of metal. This uses enormous amounts of energy. Currently, fossil fuels are used - at great expense, and causing GG emissions. At some point, with deposits becoming less rich and energy prices increasing, it becomes not economically rational to produce metals - and then we are in serious trouble.

So, there is a genuine need, and the energy is there. Your economic objections are:

''Economic
Oil, gas and coal have been much more suitable, less expensive, alternatives in most parts of the world. Concern with AGW and air pollution have partially overcome this. Geothermal exploitation is inherently more expensive since its technology is less developed and therefore more costly than conventional energy sources.''

This seems a very shortsighted view - weighing the developmental costs of geothermal energy technology against the established method; without regard to the fact that fossil fuels are limited and cause climate change. However, the oil industry has the technological ability to drill to 20,000 feet - or 3.5 miles, or more. Presumably that's in a straight line, and I appreciate what you said about directional drilling - but what if it wasn't necessary to turn corners?

Volcanoes tend to occur near to the coast because of subduction - so if you cut through the side of the volcano - downward at an angle, with pipes extending into the sea, in theory, thermal expansion would create a siphon effect - pumping water uphill and ejecting it as super-heated steam to generate electricity, and to be collected for desalination. This is just off the top of my head mind you - but it does seem theoretically possible - unless of course, you say it's not possible to drill through rock hot enough to produce this kind of effect.

[uninfinite]

Vivian, In theory, yes - I think it is a good idea - not to 'heat the world from volcanoes' exactly, but to produce power for various massive users like desalination and ore processing. I'm just spit-balling ideas; a little blue sky thinking - and in theory the energy is there, but like you say magma is dangerous stuff. Not only is it toxic and emits GG's, but it's explosive - because of the gasses dissolved into the magma under enormous pressure. Drilling near to, less yet into a magma chamber could be set off an eruption - and obvs., such is to be avoided if poss!

However, if poss - you can get clean electrical energy from it in the traditional way - which is to boil water to produce steam, to turn a turbine, to produce electricity. Using heat directly is fine, but not very versatile. Again, in theory, electricity can be used to produce hydrogen from sea-water - by electrolysis, a clean gas that produces only water vapour when burnt, and can be cooled into a liquid gas - like butane in lighters, that has 2.5 times the energy of petroleum per pound. So, there's a lot that could be done, in theory - the practice however, is where the problems lie - and I'm trying to find out if they are insurmountable.

[vivian maxine]

Vivian, In theory, yes - I think it is a good idea - not to 'heat the world from volcanoes' exactly, but to produce power for various massive users like desalination and ore processing. I'm just spit-balling ideas; a little blue sky thinking - and in theory the energy is there, but like you say magma is dangerous stuff. Not only is it toxic and emits GG's, but it's explosive - because of the gasses dissolved into the magma under enormous pressure. Drilling near to, less yet into a magma chamber could be set off an eruption - and obvs., such is to be avoided if poss!

However, if poss - you can get clean electrical energy from it in the traditional way - which is to boil water to produce steam, to turn a turbine, to produce electricity. Using heat directly is fine, but not very versatile. Again, in theory, electricity can be used to produce hydrogen from sea-water - by electrolysis, a clean gas that produces only water vapour when burnt, and can be cooled into a liquid gas - like butane in lighters, that has 2.5 times the energy of petroleum per pound. So, there's a lot that could be done, in theory - the practice however, is where the problems lie - and I'm trying to find out if they are insurmountable.

Uninfinite, about your last paragraph, I don't know what it would take to make electrical energy from steam. Well, not quite true. You just told me. What I wanted to say was this. When and where I grew up we actually did get all our heat from boiling water to steam. Remember knocking radiators? :-) The knocking was when the radiators had been turned off, gone cold and then turned back on. Steam talking to us.

We got good heat from those radiators. The boilers had to be closely watched as they could explode but I imagine we have a lot better and safer methods now.

About desalinization, why aren't we doing it? Not in connection with energy production but simple desalinization. I've wondered and wondered. The cost of transporting it to where it is needed? They transport oil via pipe lines. Why not desalinizated water? But that's another topic, I suppose. So, back to volcanoes. Dave has me re-reading my book. Thanks, Dave.

[TheVat]

It often makes more sense to use more developed energy sources located right where the salt water is, the seashore. This suggests to me such options as tidal power, coastal wind turbines, and solar distillers.

[vivian maxine]

It often makes more sense to use more developed energy sources located right where the salt water is, the seashore. This suggests to me such options as tidal power, coastal wind turbines, and solar distillers.

That is what they are doing in UK. Some are being put out in the seas for tidal and/or wind. Scotland was making a big project of that. The wind ones, of course, can be put most anywhere there is good wind. Hard on the birds, though. Nothing is ever perfect.

[jackk]

hello,
according to me

volcanic erruption is the result of global warming which is increasing now a days . This is the increasing of Earth's average surface temperature due to consequences of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation (cutting of trees) which trap heat that would otherwise escape from Earth.Global warming is the word used to describe a gradually increase in the average temperature of the Earth's atmosphere and its oceans, a modification that is believed to be permanently changing the Earth’s climate. A debate is arise among many people, and sometimes in the news, infact global warming is actual (some call it a hoax). But as a climate changes scientists looking at the facts and data agree the planet is warming. While many of them view the effects of global warming to be more substantial and more fastly occurring than others do,the scientific has estimated that on climatic changes related to global warming means the average temperature of the Earth has varied between 0.4 and 0.8 °C over the past 100 years.

[jackk]

The increasing magnitude of carbon dioxide and other greenhouse gases released by the burning of fossil fuels, land clearing, agriculture, and other human projects, are believed to be the primary sources of the global warming that has occurred over the past 50 years.

[Eclogite]

volcanic erruption is the result of global warming which is increasing now a days . This is the increasing of Earth's average surface temperature due to consequences of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation (cutting of trees) which trap heat that would otherwise escape from Earth.

Hello jackk. This is an interesting idea. It consists of four parts:
1. Global warming is occurring.
2. There has been an increase in volcanic activity.
2. Global warming "traps" heat within the Earth.
3. The trapped heat is responsible for the increase in volcanic activity.

How do these assertions stack up against the facts?

1. Excluding vested interests, the inadequately informed and fools, global warming - whatever its cause -is an established reality.

2. There is no discernible increase in volcanic activity. To validate your idea you would have to demonstrate quantitatively that the number or magnitude of eruptions had increased in a significant way over a relevant time period. Can you do so?

3. The annual flow of heat from the interior of the Earth is sufficient to melt no more than a layer of ice a few millimetres thick from the surface of the Earth. The same layer could be melted in minutes by direct sunlight. I think you are overestimating the amount of heat that needs to escape. To progress your idea you would need first to calculate the increase in interior temperature cause by the increase in surface temperature. It would be an instructive exercise, but reasonably straightforward (for an approximation).

4. You would then need to demonstrate, again quantitatively, what increase there would be in the generation of magma.

Qualitatively your suggestion does not work out. Quantitatively I think you could prove to your own satisfaction that the idea, though interesting, is wrong. Or, if the figures show otherwise, you could demonstrate convincingly that you are right. Your thoughts?