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shamus
09-20-2012, 11:44 PM
There's this diagram of the 'Global Energy Budget' which shows the paths which solar energy takes as it comes into the Earth system and how it exits. Some is reflected, some absorbed in the atmosphere, some makes it to the surface. It is all eventually emitted, according to the diagram.
That's the important point its 100% in and 100% out.

This mirrors what we know about a blackbody, or a greybody, that energy absorbed equals energy emitted- is that right?

Now some of this energy is performing work here on earth. Some of that work temporarily stores the energy, as in it grows grass. That energy is released when something eats it and releases heat or when the grass falls over and is destroyed by microbes etc. As these processes are continuous we've just introduced a time lag, and once the system is established it is clear that there is 100% in and 100% out.

But suppose I (being solar powered by eating the fruits of the earth) carry a rock up a hill and leave it in a place where it can't roll down. I've done work, I've stored energy as potential energy in the increased elevation of the rock permanently, haven't I? So wherever that sort of work takes place that energy is not ever going to be emitted is it?

Ignoring such timescales as the heat death of the universe, that is.

Chip-skiff
09-21-2012, 12:23 AM
But suppose I (being solar powered by eating the fruits of the earth) carry a rock up a hill and leave it in a place where it can't roll down. I've done work, I've stored energy as potential energy in the increased elevation of the rock permanently, haven't I? So wherever that sort of work takes place that energy is not ever going to be emitted is it?

The idea that the elevation of the rock can be increased permanently is questionable. Given the timescale for geomorphic process (long) the surface might erode out from under the rock, allowing it to roll downhill. Or the rock might thaw and freeze and crack and be root-wedged by plants, and disintegrate in place, to grit and sand and dust, carried downslope by the rain and melting snow. Or borne away by the wind.

A diagram is static. The world isn't.

Gib Etheridge
09-21-2012, 12:38 AM
You expended the same amount of energy as you stored by carrying the rock up the hill. You've done work, you've created heat, etc. That's why you got all sweaty.

shamus
09-21-2012, 12:54 AM
Gib, I agree I expended an equal amount of energy getting the rock up the hill, but I can't have released heat equal to that energy. If I did release that much heat, I can see that the energy budget diagram would be maintained, but there's energy stored in the rock. Where did that come from? I can't see that you can store it and have it leave.Chip- fair enough, let's say for 1000 years. There are aqueducts in Europe that have had rocks in them elevated for longer than that! And of course moving a rock up hill is just an example.

Kaa
09-21-2012, 01:09 AM
It is all eventually emitted, according to the diagram.
That's the important point its 100% in and 100% out.

No, the important point is "eventually". The time scale at which you operate determines which time lags you see and these matter a lot. In the really long run, the whole universe will die a cold death.

Is Earth in a more-or-less energy balanced state? Yes. It is a perfect balance? No.


...and once the system is established it is clear that there is 100% in and 100% out.

That assumes the system never changes which is not true.


I've stored energy as potential energy in the increased elevation of the rock permanently, haven't I?

Permanently?!?? Oh, dear Lord, humans :-D

But anyway, on a gross scale the Earth is in energy balance. Squint a bit, look more carefully and you'll notice that things... fluctuate.

Kaa

PeterSibley
09-21-2012, 01:18 AM
As Kaa says, timescale is all.

Plumbtex
09-21-2012, 01:33 AM
Has the energy stored in the rock changed because you moved it to a higher location? It still has the same mass, all you have done is increased the possibility of that energy being expended. You, on the other hand, have expended a large amount of energy by moving the rock.

Kaa, does the ultimate entropy still hold true with recent models of an ever expanding universe?

Gerarddm
09-21-2012, 01:42 AM
The issue of an ever expanding universe is wonderful to contemplate. Theoretically if the rate of expansion of the universe keeps expanding, that means the galaxies will continue to rush away from each other, eventually leaving our evening sky with no visible stars. Then there is the unknown monkey wrench tossed in by dark matter, and the possibility of a multiverse, not just universe...

And I don't mean wonderful as in great, fine, hunky-dory; I mean, full of wonder.

varadero
09-21-2012, 02:02 AM
By moving the rock, you will have shifted the planet on it axis by a very small amount. Only when it rolls back to where you got it from, will the planet resume its original state. Maybe!

Peerie Maa
09-21-2012, 02:52 AM
You also are forgetting that the earth started out really really hot, and is cooling down.


But the core is also radioactive, and is heating it up.

As you are not a perfectly efficient machine you will expend more energy than you impart to the rock which is why you get hot doing the work.

Complicated 'aint it :D

shamus
09-21-2012, 02:57 AM
Well Kaa, I did kind of cover that in my heat death of the universe comment! Cut me a bit of slack.
Point is, until the advent of fossil fuels, the earth was totally solar powered.
All kinds of energy was being expended on earth in useful and unuseful work yet the planet was in energy balance.
It kind of seems like getting something for nothing.
An idle thought.

shamus
09-21-2012, 02:59 AM
As you are not a perfectly efficient machine you will expend more energy than you impart to the rock which is why you get hot doing the work.

Yeah I thought of that after answering that one. My getting hot and sweaty is a measure of my inefficiency.
The wife says that too.

PeterSibley
09-21-2012, 03:08 AM
Well Kaa, I did kind of cover that in my heat death of the universe comment! Cut me a bit of slack.
Point is, until the advent of fossil fuels, the earth was totally solar powered.
All kinds of energy was being expended on earth in useful and unuseful work yet the planet was in energy balance.
It kind of seems like getting something for nothing.
An idle thought.

Oh , fossil fuels are still stored solar energy, it's just the by products of the release process that is causing problems.

varadero
09-21-2012, 03:17 AM
Oh , fossil fuels are still stored solar energy, it's just the by products of the release process that is causing problems.

Interesting arcticle I read recently dated the evolution of the fungus that causes wood to rot. The time coincided with the age of the youngest of our fossil fuels. There for we are no longer engaged in that process, and have not been since the rot set in.

Peerie Maa
09-21-2012, 03:23 AM
Well Kaa, I did kind of cover that in my heat death of the universe comment! Cut me a bit of slack.
Point is, until the advent of fossil fuels, the earth was totally solar powered.
All kinds of energy was being expended on earth in useful and unuseful work yet the planet was in energy balance.
It kind of seems like getting something for nothing.
An idle thought.


Oh , fossil fuels are still stored solar energy, it's just the by products of the release process that is causing problems.

When the fossil fuels were laid down the process may well have cooled the earth, as energy was sequestered, we have now turned the thermostat up.
Until we screwed the balance by burning fossil fuels (long term energy store) the energy we used was part of a very quick turn over cycle. The sun drives wind and evaporation (rain) which drove wind and water mills so the turnover of energy through the cycle was very quick. Furthermore if we had not drawn down some of that energy, the wind or the rivers will have expended it on erosion or heating through friction.

seanz
09-21-2012, 03:32 AM
The idea that the elevation of the rock can be increased permanently is questionable. Given the timescale for geomorphic process (long) the surface might erode out from under the rock, allowing it to roll downhill. Or the rock might thaw and freeze and crack and be root-wedged by plants, and disintegrate in place, to grit and sand and dust, carried downslope by the rain and melting snow. Or borne away by the wind.

A diagram is static. The world isn't.

Can I add "Thrown up into the air by an earthquake"? Thanks. To think, I used to believe that gravity was a constant. Now I realize that it is subject to the Very Special Theory of Relativity.


No, the important point is "eventually". The time scale at which you operate determines which time lags you see and these matter a lot. In the really long run, the whole universe will die a cold death.

Is Earth in a more-or-less energy balanced state? Yes. It is a perfect balance? No.



That assumes the system never changes which is not true.



Permanently?!?? Oh, dear Lord, humans :-D

But anyway, on a gross scale the Earth is in energy balance. Squint a bit, look more carefully and you'll notice that things... fluctuate.

Kaa

Yeah, probably. (http://en.wikipedia.org/wiki/Entropy)

Now, here's a thing. What if Shamus transports his rock uphill using electric power, and the electricity is produced from geo-thermal energy?

How's everybody's balance now?

shamus
09-21-2012, 03:32 AM
Which raises the question if they had been oxidised at the time instead of sequestered would we have arrived where we're going already?
My thought is not, more time for carbonates to form and drop to the bottom of the sea.

Peerie Maa
09-21-2012, 03:37 AM
Which raises the question if they had been oxidised at the time instead of sequestered would we have arrived where we're going already?
My thought is not, more time for carbonates to form and drop to the bottom of the sea.

We would not even be here, evolution would have taken a different path.

seanz
09-21-2012, 03:46 AM
Yes, we have been around for about 200,000 years.......things could easily be different.

But, just removing fossil fuels from the equation might be 'interesting'. Imagine the Agricultural Revolution (Britain) and then no coal to stoke the Industrial Revolution.

varadero
09-21-2012, 03:49 AM
We may be here, but the last 200 years would have been a very different story.

varadero
09-21-2012, 03:55 AM
And when we have used them all up, and returned the balance to that which it would have been had they not fossilised, will we eventually regress to the condition we would have been had they not existed in the first place? Modern man just a blip in the history of the planet all down to the existance or non existence of a wood eating fungus?

Peerie Maa
09-21-2012, 04:03 AM
Yes, we have been around for about 200,000 years.......things could easily be different.

But, just removing fossil fuels from the equation might be 'interesting'. Imagine the Agricultural Revolution (Britain) and then no coal to stoke the Industrial Revolution.

We would have stalled in the pre steam age. No electricity, no pharmaceuticals, no plastics, no materials technology, everything metal made out of wrought or cast iron (very expensive and rare as the woods are felled for the charcoal needed to smelt and process it) brass or bronze copper and lead. Life lived at the pace of a good horse, & without pharmaceuticals, lower average life expectancy and a smaller first world population.

P.I. Stazzer-Newt
09-21-2012, 04:25 AM
It is a bad mistake to think of rocks as permanent.


"The result, therefore, of our present enquiry is, that we find no vestige of a beginning,–no prospect of an end."

"when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind"

PeterSibley
09-21-2012, 04:31 AM
And when we have used them all up, and returned the balance to that which it would have been had they not fossilised, will we eventually regress to the condition we would have been had they not existed in the first place? Modern man just a blip in the history of the planet all down to the existance or non existence of a wood eating fungus?

http://www.slu.se/en/about-slu/fristaende-sidor-eng/whats-on/news/2012/7/analysis-of-fungal-genome-clue-to-why-carboniferous-period-ended-300-million-years-ago/

seanz
09-21-2012, 05:13 AM
We would have stalled in the pre steam age. No electricity, no pharmaceuticals, no plastics, no materials technology, everything metal made out of wrought or cast iron (very expensive and rare as the woods are felled for the charcoal needed to smelt and process it) brass or bronze copper and lead. Life lived at the pace of a good horse, & without pharmaceuticals, lower average life expectancy and a smaller first world population.


Sort of (I think), the Agricultural Revolution (and population increases) predate the spread of the Industrial Revolution. I think that there could have been a massive environmental disaster caused by desertification (the Ag revolution required ferrous tools and that requires charcoal) ) and (this will give Kaa a laugh) a Malthusian catastrophe.

Peerie Maa
09-21-2012, 05:21 AM
Sort of (I think), the Agricultural Revolution (and population increases) predate the spread of the Industrial Revolution. I think that there could have been a massive environmental disaster caused by desertification (the Ag revolution required ferrous tools and that requires charcoal) ) and (this will give Kaa a laugh) a Malthusian catastrophe.

Possibly pessemistic. The charcoal industry depends on coppiced woods worked in rotation. There would have been a change in the nature of how the forests were managed, and the limited supply of charcoal will have limited the supply of new iron but it need not become as bad as that.

shamus
09-21-2012, 05:49 AM
Speaking of the agricultural revolution, I was taught that in pre revolutionary France the farmers harvested only about six grains of wheat for every one planted. Did anyone else learn this or did I have a dud teacher. I've often wondered whether agriculture had been much more productive earlier and had fallen into a decline- possibly even due to cold weather. Looking at Bruegel's "The Corn Harvest", painted pre 1600 I think, it looks to be a much better crop than that. The peasants don't look too stressed either, lolling about with their jugs of refreshment.

John Smith
09-21-2012, 05:52 AM
I'm not sure I get the point of this thread. We use energy simply moving around. When we use a machine of some sort to move us around, like an automobile, we use enough energy to move us and the car.

There is a degree of heat created buy internal combustion engines. A car that moved us around and didn't create heat might be impossible. I'm sure that electric cars have a heat factor. I'v always viewed some heat as the result of inefficiency. Short out a battery and you get considerable heat; even from those we use in flashlights. I suspect using the flashlight may generate the same amount of heat, but over a longer period of time.

sometimes we use energy for the distinct purpose of creating heat. Sometimes we use energy to keep things cool, but that also creates heat. Unless we move something through a vacuum, there is some friction. That causes heat, although usually not enough to notice.

seanz
09-21-2012, 06:01 AM
Possibly pessemistic. The charcoal industry depends on coppiced woods worked in rotation. There would have been a change in the nature of how the forests were managed, and the limited supply of charcoal will have limited the supply of new iron but it need not become as bad as that.

:)

Honestly, sometimes you can't be too pessimistic when it comes to Production vs Environment.
;)

Without steel (as well as steam/coal) the progress of the 19th C wouldn't have happened as it did. No large sewage pumps. Think of the consequences!
:D

John Smith
09-21-2012, 06:08 AM
For every upside, there seems to be a downside.

Kaa
09-21-2012, 09:51 AM
Kaa, does the ultimate entropy still hold true with recent models of an ever expanding universe?

Not sure what do you mean by "ultimate entropy" -- is it the law that in a closed system entropy can only increase? I don't see why the expanding universe model would have any trouble with this law...

Kaa

Kaa
09-21-2012, 09:55 AM
Point is, until the advent of fossil fuels, the earth was totally solar powered.

(a) Fossil fuels are stored solar power.

(b) Some energy is and has been coming from nuclear processes.

(c) Again, on most any given time scale the energy balance will not be exact. At some points the Earth absorbs more energy from the Sun than it emits, at other points it absorbs less than it emits. The system is not stable, at best it's a chaotic trajectory around an attractor.

Kaa

Dan McCosh
09-21-2012, 09:59 AM
You are looking at a food chain of energy conversion. The energy stored in the rock is converted from another source. It is waiting to be converted again to another form. It is still in balance.

Kaa
09-21-2012, 09:59 AM
We would have stalled in the pre steam age. No electricity, no pharmaceuticals, no plastics, no materials technology, everything metal made out of wrought or cast iron (very expensive and rare as the woods are felled for the charcoal needed to smelt and process it) brass or bronze copper and lead. Life lived at the pace of a good horse, & without pharmaceuticals, lower average life expectancy and a smaller first world population.

I rather doubt that. Humans are an inventive and a persistent lot. I don't see, for example, how "no electricity, no pharmaceuticals" necessarily follow from a hydrocarbon-poor world. Penicillin is just a mold on rye...

Kaa

Captain Intrepid
09-21-2012, 10:23 AM
That assumes the system never changes which is not true.

The system is definitely 100% energy in 100% energy out (ignoring higher level physics). The quality of the energy out though cannot be as high as the quality of the energy in. That's the definition of entropy.

Kaa
09-21-2012, 10:42 AM
The system is definitely 100% energy in 100% energy out (ignoring higher level physics).

Over which time period? Absorbing and emitting energy are continuous processes, over which periods are you integrating to come to your perfect balance of in=out? :-)

Kaa

Peerie Maa
09-21-2012, 10:44 AM
I rather doubt that. Humans are an inventive and a persistent lot. I don't see, for example, how "no electricity, no pharmaceuticals" necessarily follow from a hydrocarbon-poor world. Penicillin is just a mold on rye...

Kaa
Electricity uses iron in the armatures and stators, and iron and steel in the prime movers that drive the generators. You can't make a nations supply of pharmaceuticals in glass equipment and
The chemical and pharmaceutical industries are currently built upon feedstocks from petroleum. Chemists and
engineers will need to alter the production methods
towards using biomass-derived chemicals so that these
industries can become sustainable.
from http://www.rsc.org/images/biomass_tcm18-185654.pdf
So both of those industries would not have developed past the very small scale novelty/luxury market.

wardd
09-21-2012, 10:54 AM
Has the energy stored in the rock changed because you moved it to a higher location? It still has the same mass, all you have done is increased the possibility of that energy being expended. You, on the other hand, have expended a large amount of energy by moving the rock.

Kaa, does the ultimate entropy still hold true with recent models of an ever expanding universe?

my question is when it grows cold enough is there a time when it ceases to be a universe

Kaa
09-21-2012, 11:00 AM
So both of those industries would not have developed past the very small scale novelty/luxury market.

I don't see how you come to this conclusion. You can perfectly well make a nation's supply of pharmaceuticals in glass equipment -- they'd be more expensive but certainly more than the "novelty/luxury" market. Before antibiotics any small scratch could be fatal -- how much would you be willing to invest in (relatively inefficient) manufacturing of pharmaceuticals to fix that?

Sure, a world with expensive energy would look different from ours. And I don't know how the humanity would have adapted to it. But I am pretty sure it would have, somehow. The Industrial Revolution wouldn't have happened in the XVIII century, but eventually it would have happened anyway, though in a different shape and form.

Kaa

wardd
09-21-2012, 11:09 AM
I don't see how you come to this conclusion. You can perfectly well make a nation's supply of pharmaceuticals in glass equipment -- they'd be more expensive but certainly more than the "novelty/luxury" market. Before antibiotics any small scratch could be fatal -- how much would you be willing to invest in (relatively inefficient) manufacturing of pharmaceuticals to fix that?

Sure, a world with expensive energy would look different from ours. And I don't know how the humanity would have adapted to it. But I am pretty sure it would have, somehow. The Industrial Revolution wouldn't have happened in the XVIII century, but eventually it would have happened anyway, though in a different shape and form.

Kaa

the thing is this is the world we have because it's the world that works

Peerie Maa
09-21-2012, 01:00 PM
I don't see how you come to this conclusion. You can perfectly well make a nation's supply of pharmaceuticals in glass equipment -- they'd be more expensive but certainly more than the "novelty/luxury" market. Before antibiotics any small scratch could be fatal -- how much would you be willing to invest in (relatively inefficient) manufacturing of pharmaceuticals to fix that?

Sure, a world with expensive energy would look different from ours. And I don't know how the humanity would have adapted to it. But I am pretty sure it would have, somehow. The Industrial Revolution wouldn't have happened in the XVIII century, but eventually it would have happened anyway, though in a different shape and form.

Kaa
Its not about efficiency but the size of the reactors that you can manufacture in a charcoal fired furnace, blown by mouth. We have to be talking about small volumes here.
Thishttp://www.chemistryinnovation.co.uk/stroadmap/files/gfx/7ACA%20bioreactors%20CP3.jpg
is a small part of Glaxosmithkline local plant, I can't see that lot being made out of anything but stainless steel.

Kaa
09-21-2012, 02:22 PM
Its not about efficiency but the size of the reactors that you can manufacture in a charcoal fired furnace, blown by mouth. We have to be talking about small volumes here.

And why in the world would you be limited to "blown by mouth" sizes..?

In any case, running a hundred small reactors instead of one big reactor is going to be more expensive, but both setups will produce the same amount of product.


I can't see that lot being made out of anything but stainless steel.

Yes, in this real world where stainless steel is reasonably cheap. The alternate-reality world without hydrocarbons will clearly be different, but I still don't see hard limits on e.g. pharmaceuticals production.

Kaa

Peerie Maa
09-21-2012, 02:29 PM
And why in the world would you be limited to "blown by mouth" sizes..?


Kaa
How else you gonna make them? Not a lot of steel machinery remember.

Kaa
09-21-2012, 02:35 PM
How else you gonna make them? Not a lot of steel machinery remember.

Glass can be "welded" relatively easily. Especially given that you don't necessarily need glass tanks, you only need glass-lined tanks.

Kaa

Peerie Maa
09-21-2012, 02:37 PM
Glass can be "welded" relatively easily. Especially given that you don't necessarily need glass tanks, you only need glass-lined tanks.

Kaa
I guess that is a process needing heat. How does it work?

Kaa
09-21-2012, 02:46 PM
I guess that is a process needing heat. How does it work?

Oh please. I'm not an expert on glass manufacturing, but do you really think that local application of high heat is impossible without oil or gas? For one thing, if you can do it using coal you can do it using charcoal. Yes, it's going to be more expensive in an energy-poor world, but it can be done.

Kaa

Peerie Maa
09-21-2012, 03:34 PM
Nope. Working glass either needs a large furnace or a local gas flame. No coal - no gas, you don't make gas from charcoal, sorry :D

Kaa
09-21-2012, 04:08 PM
No coal - no gas

Rubbish.

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

Kaa

wardd
09-21-2012, 04:43 PM
Nope. Working glass either needs a large furnace or a local gas flame. No coal - no gas, you don't make gas from charcoal, sorry :D

wood gas

Peerie Maa
09-21-2012, 04:45 PM
wood gas
How do you make it? In a big steel retort?
Then you have to store and transport it.

There is so much that we take for granted.;)

wardd
09-21-2012, 04:47 PM
How do you make it? In a big steel retort?
Then you have to store and transport it.

There is so much that we take for granted.;)

you could use brick

wardd
09-21-2012, 04:50 PM
describe a world that could support life as we know it that wouldn't over geologic time produce hydro carbon fuel

otherwise this is a bad scifi discussion of what if

seanz
09-21-2012, 05:21 PM
How do you pressurize your wood gas? If the acetylene was at atmospheric pressure, it'd stay in the bottle, right. That big steel cylinder......

shamus
09-21-2012, 05:49 PM
Yesterday I carried my rock up the hill. Everyone seems to agree that I temporarily stored some energy in the form of potential energy in the new position of the rock. Most seem to agree that I introduced a lag into the energy balance.
This morning I changed my mind and carried it down the hill. That was easier than carrying it up the hill, but it was still work. I placed the rock very gently back in its original position. In what form is the energy I stored up the hill overnight now free to exit the earth?

PeterSibley
09-21-2012, 05:52 PM
Nope. Working glass either needs a large furnace or a local gas flame. No coal - no gas, you don't make gas from charcoal, sorry :D

I see a cunning use for night soil collection.:d

seanz
09-21-2012, 05:55 PM
Yesterday I carried my rock up the hill. Everyone seems to agree that I temporarily stored some energy in the form of potential energy in the new position of the rock. Most seem to agree that I introduced a lag into the energy balance.
This morning I changed my mind and carried it down the hill. That was easier than carrying it up the hill, but it was still work. I placed the rock very gently back in its original position. In what form is the energy I stored up the hill overnight now free to exit the earth?

The only 'energy' the rock had was to get to the bottom of the hill. Energy expended. Show's over.

PeterSibley
09-21-2012, 06:02 PM
Awwww shucks .........

seanz
09-21-2012, 06:24 PM
Through and through..........

http://www.stuff.co.nz/the-press/news/christchurch-earthquake-2011/7680851/The-red-zone-in-the-hills

shamus
09-21-2012, 07:05 PM
Good grief!

seanz
09-21-2012, 07:09 PM
Good grief!

Bit of energy there, eh?
;)

I posted earlier in the thread about how inconsistent gravity could be. Small boulders that were half buried in the ground on the Port Hills were popped up into the air back in the Feb 2011 quake.

Peerie Maa
09-22-2012, 02:20 AM
Yesterday I carried my rock up the hill. Everyone seems to agree that I temporarily stored some energy in the form of potential energy in the new position of the rock. Most seem to agree that I introduced a lag into the energy balance.
This morning I changed my mind and carried it down the hill. That was easier than carrying it up the hill, but it was still work. I placed the rock very gently back in its original position. In what form is the energy I stored up the hill overnight now free to exit the earth?
It already has. The internal friction in your muscles and joints heated you up and you transferred that heat to the atmosphere.

PeterSibley
09-22-2012, 03:01 AM
Good grief!

Potential e converted to kinetic .

seanz
09-22-2012, 03:15 AM
Hmmm......when I think about it.....the rock that smashed through that house was storing energy created by geo-thermal power. There's a coincidence.

PeterSibley
09-22-2012, 03:20 AM
The universe is in balance my son.