Interesting Items...

Geophysicists believe that heat flows from Earth’s interior into space at a rate of about 44 × 10^12 W (TW). What is not clear, however, is how much of this heat is primordial – left over from the formation of the Earth – and how much is generated by radioactive decay.
But in the first paragraph it refers to 50% from radioactivity. As it is heat flow tidal wouldn't be a likely cause. Looks like that old QI favourite from years ago "Nobody Knows".
 
As it is heat flow tidal wouldn't be a likely cause.
I don't see why not. The spin of the Earth raises tidal bulges in the rock, albethey not as significant as the ocean tides, and the continual pulling and pushing must result in heat – the energy for this comes out of the Moon's orbit (the Moon is drifting away).
 
I don't see why not. The spin of the Earth raises tidal bulges in the rock, albethey not as significant as the ocean tides, and the continual pulling and pushing must result in heat – the energy for this comes out of the Moon's orbit (the Moon is drifting away).
Indeed the energy all comes from somewhere. I recall once watching some "science" program and it said Jupiter and Saturn drifted inwards during our solar system formation due to random pertubations in their orbits. Random!!?? I had to resist the urge to hurl something at the TV. There's nothing random about any of it, you have to work out where the energy is transferred. In the case of planetary orbits drifting inwards during solar system formation it is impacts with orbital debris gradually slowing the planets down.
 
After 4.5 billion years (or whatever it is), is there really still going to be significant trapped heat... especially if it is escaping at 20TW???
 
The wiki article on it seems quite good.
I haven't read that yet, printed it (to PDF) for later.
After 4.5 billion years (or whatever it is), is there really still going to be significant trapped heat... especially if it is escaping at 20TW???
I find it difficult to believe, but clearly it must be the case, that after that many years plus the Sun is still burning and that molten lava still emerges from the Earth. My knowledge and imagination are sadly lacking.
 
I find it difficult to believe, but clearly it must be the case, that after that many years plus the Sun is still burning and that molten lava still emerges from the Earth. My knowledge and imagination are sadly lacking.
I was referring to primordial heat. We have discussed that there is still heat being generated.

So far as the Sun goes, it was calculations of how much material would have to be burned for it to be as old as geological time that proved it must be nuclear powered. Given its mass of mostly hydrogen, the energy available from converting that to helium means the Sun is only a small fraction of the way through its life.
 
The wiki article on it seems quite good. (https://en.wikipedia.org/wiki/Geothermal_gradient). Nice graphs of the temperature gradient too - it gets very hot very quickly in the upper layers as you descend!
On a quick skim, I can't see any estimate for how much of the current heat is primordial.

Obviously there will be a significant proportion if it is being continually topped up, but what I would like to see is a figure for the core temperature if it were not being topped up and the Earth had been allowed to cool without radioactive decay and tidal forces.
 
spontaneous combustion
My washing machine tried that last week! :mad:
Fortunately it was smoke without fire. A spray of fabric refresher got rid of the nasty smell in the clothes. Time for a new machine. More expense and just after the water bill. (Don't call me Bill).

Of course, it wasn't spontaneous - it had just finished a wash cycle when I noticed the smoke. Most battery fires (usually electric bicycles) seem to occur when charging. Not sure what the main cause of EV combustion is.
 
My washing machine tried that last week! :mad:
Fortunately it was smoke without fire. A spray of fabric refresher got rid of the nasty smell in the clothes. Time for a new machine. More expense and just after the water bill. (Don't call me Bill).

Of course, it wasn't spontaneous - it had just finished a wash cycle when I noticed the smoke. Most battery fires (usually electric bicycles) seem to occur when charging. Not sure what the main cause of EV combustion is.
If you have not sorted out a new machine yet this place is worth a look, I have bought 3 things from them in the past few months and saved several hundred pounds compared to the exact same items from Currys and they offer free delivery and in some cases free recycling also joining their club for £19.99 guarantees free recycling and gives additional discounts for a year for less than a single Currys recycling fee. After some research I bought a LG washing machine which had a really long parts and labour guarantee and good reviews and am very impressed with it.


https://markselectrical.co.uk/f4y511gbln1_lg-washing-machine £389 free delivery, free recycling.
https://www.currys.co.uk/products/lg-y500-series-ai-direct-d £549 + £20 delivery + £25 recycling.
 
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Yes I've sorted a replacement including recycling and installation (probably could do it myself, but I'm not as flexible as I used to be and the connections involve a bit of bending which could play havoc with my back). Currys didn't have the item in stock. In any case, Currys' website always misbehaves when I access it.

Never heard of Marks Electrical before today.
 
Never heard of Marks Electrical before today.
I only discovered them recently, I looked on a manufactures site for an an oven I was interested in and it listed half a dozen stockists including Currys, John Lewis and Marks Electrical which had the oven for £180 less than the others, the name suggests a small independent outfit but I think they are quite major players, great customer support too.
 
I tend to buy new socks with a full supply of all the same colour/pattern. That way there is only ever one odd sock at most by the time it comes to replace them.
 
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