Thread: Journey to the Centre

There’s a old riddle that asks ‘What gets bigger by taking more away from it?’ Ans: The hole. Seems like it also gets more interesting. This article speaks of the world’s deepest man made hole.

https://www.treehugger.com/the-world...al-cap-4863210

Temperatures prevented further drilling but along the way they made discoveries, some new and some dispelling of old truths, as well as exposing how little we know of what’s below us.

You don’t hear much about capturing geothermal energy. There’s plenty of warmth down there, just need to transfer it topside. Too bad we couldn’t drill a 12km hole beneath every edifice, control and enable heat. Suspect costs of drilling are exorbitant but new techniques do come along. There may be an environmental impact but no idea what that might be.

Originally Posted by zinjanthropos

There’s a old riddle that asks ‘What gets bigger by taking more away from it?’ Ans: The hole. Seems like it also gets more interesting. This article speaks of the world’s deepest man made hole.

https://www.treehugger.com/the-world...al-cap-4863210

Temperatures prevented further drilling but along the way they made discoveries, some new and some dispelling of old truths, as well as exposing how little we know of what’s below us.

You don’t hear much about capturing geothermal energy. There’s plenty of warmth down there, just need to transfer it topside. Too bad we couldn’t drill a 12km hole beneath every edifice, control and enable heat. Suspect costs of drilling are exorbitant but new techniques do come along. There may be an environmental impact but no idea what that might be.

Capturing geothermal energy is the basis of most domestic heat pump systems. Geothermal Heat, Ground Source Pumps, Renewable Energy Source

[QUOTE=exchemist;631501]

Originally Posted by zinjanthropos

There’s a old riddle that asks ‘What gets bigger by taking more away from it?’ Ans: The hole. Seems like it also gets more interesting. This article speaks of the world’s deepest man made hole.

Capturing geothermal energy is the basis of most domestic heat pump systems. Geothermal Heat, Ground Source Pumps, Renewable Energy Source

I see the odd heat pump here and there when driving around. Is it popular where you are? People here satisfied with nat gas or because of our proximity to Niagara, electricity. I was thinking about geothermal on an industrial scale, supplying cities with heat. I figure it’s too costly to build infrastructure. Still require electricity, no?

[QUOTE=zinjanthropos;631504]

Originally Posted by exchemist

Originally Posted by zinjanthropos

There’s a old riddle that asks ‘What gets bigger by taking more away from it?’ Ans: The hole. Seems like it also gets more interesting. This article speaks of the world’s deepest man made hole.

Capturing geothermal energy is the basis of most domestic heat pump systems. Geothermal Heat, Ground Source Pumps, Renewable Energy Source

I see the odd heat pump here and there when driving around. Is it popular where you are? People here satisfied with nat gas or because of our proximity to Niagara, electricity. I was thinking about geothermal on an industrial scale, supplying cities with heat. I figure it’s too costly to build infrastructure. Still require electricity, no?

Yes, a heat pump uses electricity. But you get several times the energy out that you put in. Domestic heat pump systems are likely to become a lot more widespread, once we have regulations forbidding the use of natural gas to heat newly built houses, which is coming some time in the next decade or so. I've even looked into retrofitting a heat pump to my Victorian house in London, but the costs are too high, as it would mean replacing all the radiators as well (Heat pumps are only efficient if they don't have to raise the temperature of the heat too far, so typically you get a lot of warmish water circulating, rather than a smaller amount of really hot water, as in a conventional gas boiler system. Ideal for underfloor heating, but not much good with the smallish area of conventional radiators. So better for newbuilds than retrofitting.)

I can't see any special advantage in trying to use a heat pump on a city-wide scale. But some towns with access to volcanic, high temperature, heat (e.g. in Iceland, New Zealand), do that already, I think.

The Earth's crust is constantly being recycled. Saw a 10 year old report that suggested it takes 500 million years for total recycling whereas scientists originally thought it was 2 billion years. Can't find anything else contrary to that 500my hypothesis. I don't know when recycling began but one can extrapolate the crust being recycled at least a few times already. With it goes the evidence of the 500 million years prior i figure. Sure there's going to be random misses, some rock avoids recycling just by luck, so should there be a lot of rock present day that's older than 500 million years?

Seems to me there's a fair amount of extremely old rock still around, including Hudson's Bay area here in Canada, estimated at over 4.2 billion years old. Canadian Shield composed of rock billions of years old. Other than volcanic islands and areas surrounding volcanoes, where can one find rock less than 500 million years old?

Originally Posted by zinjanthropos

The Earth's crust is constantly being recycled. Saw a 10 year old report that suggested it takes 500 million years for total recycling whereas scientists originally thought it was 2 billion years. Can't find anything else contrary to that 500my hypothesis. I don't know when recycling began but one can extrapolate the crust being recycled at least a few times already. With it goes the evidence of the 500 million years prior i figure. Sure there's going to be random misses, some rock avoids recycling just by luck, so should there be a lot of rock present day that's older than 500 million years?

Seems to me there's a fair amount of extremely old rock still around, including Hudson's Bay area here in Canada, estimated at over 4.2 billion years old. Canadian Shield composed of rock billions of years old. Other than volcanic islands and areas surrounding volcanoes, where can one find rock less than 500 million years old?

Yes that's clearly the case, seeing as continental crust is lighter than oceanic and sits on it like a raft. The oceanic crust gets renewed like a conveyor belt but subduction of continental crust is a far more hit and miss affair. We have rocks that are >3bn years old, which are what we use for evidence about early life, the Great Oxygenation Event and other information about the early earth.