Why electric planes are inevitable

A vast majority of US cropland is not for food production, but rather the heavily subsidized corn industry for ethanol to be used in fuel. That whole process ends up producing more carbon than it otherwise would straight from gasoline which is just asinine.

So if we converted all of the farmland dedicated to ethanol production to solar farms we would net a huge energy boost for the country, in my mind your comment isnt really a loss.
You may be right.
 
All autonomous electric transport is suffering from the low energy density problem and ultimately will be the same low margin business, because it will carry battery [dead]weight which doesn't pay money to transport it and therefore should be considered as a lost opportunity profit. No matter what sleek CF airframe one puts around electric propulsion, the end result won't be an economic solution. Powerplant efficiency can be estimated easily:

LiON battery energy density: 265 Wh/kg
Jet-A fuel energy density: 42.8 MJ/kg == 11888.8 Wh/kg

Jet-A power plant and energy source is 44 times more efficient than electric propulsion per unit of mass. On top of this producing batteries is highly energy intensive process on its own. Just read Manhattan institute report on the true cost of "green" energy machines. On top of this batteries will require utilization, where is traditional fuel is directly expendable.

This plane fire remined me a story which started with $465m grant of public money to a company run by a techno swindler and ending up with this:
Did you consider that a greater proportion (by well over 2x) of the electricity carried will be turned into propulsive force, versus the kerosene?
There are many problems, but we've not yet optimized lithium batteries, let alone some of the outliers.
 
Sugar beets, and we grew a lot of them when I was still out on the family farm, contain a remarkably low concentration of sugar. Taste a chunk, if you get the opportunity. Hardly any trace of sweetness.
What sugar beets are really good at is generating biomass, huge tonnage of beets from an acre of land. Getting the sugar out takes an enormous amount of energy; it only works economically because beet growing regions tend to also have cheap hydropower available. But it would be an expensive way to make alcohol for fuel.
Maybe they have improved the yield of sugar beets? The roots are about 20% sugar, now.
https://en.wikipedia.org/wiki/Sugar_beet

Nebraska doesn't have hydropower, yet it produces quite a bit of sugar beets:
https://cropwatch.unl.edu/sugarbeet-history-nebraska
https://farmflavor.com/nebraska/nebraska-crops-livestock/nebraska-sugar-beets-confection-perfection/

Nebraska is the fourth highest producer of sugar beets:
https://en.wikipedia.org/wiki/Sugar_industry_of_the_United_States

The other states that produce more aren't known for hydropower, either.
 
Did you consider that a greater proportion (by well over 2x) of the electricity carried will be turned into propulsive force, versus the kerosene?
There are many problems, but we've not yet optimized lithium batteries, let alone some of the outliers.
No, we haven't reached the limits of lithium batteries. Here's one new example with a lot higher energy capacity and faster recharge than anything we have now:
https://ucsdnews.ucsd.edu/pressrelease/meng_science_2021
 
Nebraska is the fourth highest producer of sugar beets:
https://en.wikipedia.org/wiki/Sugar_industry_of_the_United_States

The other states that produce more aren't known for hydropower, either.

Nebraska is 6th, it appears from the link, producing only 4% of the nation's sugar beets. But Minnesota and Michigan are much higher than I would have thought, and it's true that they don't have a lot of hydro power.
It's still an expensive way to make sugar, but since nearly all of the US isn't well suited for growing sugar cane, it's what we've got.
 
No, we haven't reached the limits of lithium batteries. Here's one new example with a lot higher energy capacity and faster recharge than anything we have now:
https://ucsdnews.ucsd.edu/pressrelease/meng_science_2021

These new promising battery types and technology seem to be announced almost weekly. The problem is taking a one off battery created in a lab and translating it to mass production with the necessary quality and reliability is a entirely different animal. That where 99% of new battery technology fails.
 
You can use Mr. Moon to do it with tidal power generation. Of course, that has upsides and downsides too.

Another (very) long term downside is that anything that it increases the surface friction of the planet, slowing its rotation ever so slightly. The same applies to wind and hydro - the energy does have to come from somewhere. I think the slower rotation of the earth will cause the moon to increase its distance to maintain the angular momentum of the system.

But not something we’ll have to worry about any time soon!
 
These new promising battery types and technology seem to be announced almost weekly. The problem is taking a one off battery created in a lab and translating it to mass production with the necessary quality and reliability is a entirely different animal. That where 99% of new battery technology fails.
So you are suggesting that we stop research? If we took that attitude, we never will have electric planes nor better electric cars. In fact, we'll never have anything new. Do you truly think people can't learn from failures, fix the problems, and eventually make a good product?

The lithium ion batteries we use now took a long time to become a commercial product. The initial work on lithium batteries were in the 1970's, a decent prototype was made in 1985, and it was commercialized in 1991. It took more time for those batteries to be generally used. So it was roughly 20 years before they became accepted. The acceptance time for a new battery will be reduced now
 
Another (very) long term downside is that anything that it increases the surface friction of the planet, slowing its rotation ever so slightly. The same applies to wind and hydro - the energy does have to come from somewhere. I think the slower rotation of the earth will cause the moon to increase its distance to maintain the angular momentum of the system.

But not something we’ll have to worry about any time soon!
For wind and hydro, the energy source is the sun.
 
In fact, we'll never have anything new
I think that's a bit of a slippery slope..

If people kept jumping off buildings they'll eventually figure out they can't fly.. even if flapping their arms really really hard slows their descent rates by fractions of a mile per hour.. "keep practicing! eventually we'll land without dying, and then land without breaking anything, and then we'll be able to fly like birds!"

For comparison
-the first patent for a jet engine was in 1930.. by 1939 it was flying.. and within 20 years we had supersonic commercial air travel, and 30 years later efficient high bypass engines.. to go from a patent to 777/787/A350 engine tech in about 6 or so decades is incredible
-by comparison, the first battery was made in 1800.. and.. well.. look where we are despite billions of dollars and tons of very smart people working on them. It's a strawman argument to say that the advancement of electric tech is stalled due to political reasons, or otherwise.. there are simple quantum level limits to what you can do with it

That USCD article noted above.. was very well written, they admit that real world applications are limited, that charge cycles reduce the batteries retention. Their experiment showed only 80% retention after 500 cycles.. if the average airliner logs 40K cycles.. how do you get there? Keep putting new batters in the planes every 1-2 months? Where does all that get mined and recycled? I'm all for the advancement of our industry, my disdain for the disgraceful state of our aviation tech, namely engines, is well know. But, we need to be realistic

Not to mention that lithium mining and battery development is not an environmentally neutral process. Burning fossil fuels, chemically speaking.. is fairly clean. Mining lithium, disposing of it, is remarkably toxic.
 
I think that's a bit of a slippery slope..
And the argument I replied to wasn't a slippery slope?
"They announce new things all the time, they don't work, so we should stop trying"

If people kept jumping off buildings they'll eventually figure out they can't fly.. even if flapping their arms really really hard slows their descent rates by fractions of a mile per hour.. "keep practicing! eventually we'll land without dying, and then land without breaking anything, and then we'll be able to fly like birds!"
What does this have to do anything? Lithium batteries have continuously improved since 1991.

[QUOTE="Tantalum, post: 3151514, member: 30125"
For comparison
-the first patent for a jet engine was in 1930.. by 1939 it was flying.. and within 20 years we had supersonic commercial air travel, and 30 years later efficient high bypass engines.. to go from a patent to 777/787/A350 engine tech in about 6 or so decades is incredible
-by comparison, the first battery was made in 1800.. and.. well.. look where we are despite billions of dollars and tons of very smart people working on them. It's a strawman argument to say that the advancement of electric tech is stalled due to political reasons, or otherwise.. there are simple quantum level limits to what you can do with it[/quote] Jets are a different technology which is rather mature. It makes as much sense to compare jets to computing power as it does to compare them to batteries. We can probably get another 10 fold improvement in battery capacity, but that's just my opinion. What's the comment about political reasons about? I never brought that up.

[QUOTE="Tantalum, post: 3151514, member: 30125"That USCD article noted above.. was very well written, they admit that real world applications are limited, that charge cycles reduce the batteries retention. Their experiment showed only 80% retention after 500 cycles.. if the average airliner logs 40K cycles.. how do you get there? Keep putting new batters in the planes every 1-2 months? Where does all that get mined and recycled? I'm all for the advancement of our industry, my disdain for the disgraceful state of our aviation tech, namely engines, is well know. But, we need to be realistic

Not to mention that lithium mining and battery development is not an environmentally neutral process. Burning fossil fuels, chemically speaking.. is fairly clean. Mining lithium, disposing of it, is remarkably toxic.[/QUOTE]
What do you think happens to lead-acid batteries now? Almost all of them are recycled:
https://www.recyclingtoday.com/article/battery-council-international-lead-battery-recycling/

Why do you think we will continue to use lithium? Batteries based on sodium and other metals are being explored but are a long way off.
Why do you think think they won't improve the battery in the UCSD press release? Until this year, silicon wasn't very promising at all!
Why do you think no other than you is thinking about recycling the batteries, of whatever chemistry? Why do you think it isn't happening, now?
https://spectrum.ieee.org/lithiumion-battery-recycling-finally-takes-off-in-north-america-and-europe
 
"They announce new things all the time, they don't work, so we should stop trying"
Sure, it is. But I get the impression some people place a little too much faith in EV tech breakthroughs, we need a modicum of careful reality check. This group is smarter than most, I'd say.. but most people hear the word "electric" or "EV" or "hybrid" and automatically assume it's the magic pill to save the world. They see a Tesla drive by, watch the YouTube that spurred this thread, and think "gee, duh!" without getting the full picture of why we're not actually there.. yet.. and at this rate are still a very long ways off. A tiny two place electric plane that has no practical application is hardly a case-and-point of this technology's real world potential. The Airbus E-fan flew in 2014.. are we that much closer today than we were then?

Lithium batteries have continuously improved since 1991
But in 3 decades those improvements are tiny, at least compared to 3 decades of improvements in virtually every other (generally much less well funded) field

..hopefully! it's a very real concern, from the article
"
Founded in late 2016, the company is part of a booming industry focused on preventing tens of thousands of tons of lithium-ion batteries from entering landfills. Of the 180,000 metric tons of Li-ion batteries available for recycling worldwide in 2019, just a little over half were recycled. As lithium-ion battery production soars, so does interest in recycling.
"
.. as it is now, that's a very depressing metric that nearly 90,000 tons of Li-ion batteries went to landfills... and I find that stat is unusually high, the stuff I've read puts that figure usually under 25% getting recycled, in this case just 5% https://grist.org/politics/most-lit...in-a-landfill-a-new-bill-aims-to-change-that/ BBC also quoted 5% https://www.bbc.com/news/business-56574779 Science direct has some peer reviewed journals on this as well. Most of these toxic landfills are out of sight, and hence, out of mind, and often in impoverished countries. Mind you, Tesla has cobalt in their batteries. The world's largest source of cobalt is the DRC (Democratic Republic of Congo), allegedly up to 40,000 children work in the cobalt mines. Mr Fancy-Pants Silicon Valley tech executive driving his Tesla might be individually adding less carbon to the atmosphere, but is his (or her's) general ecological and sociological impact to the world less severe?



I'm not actually disagreeing with you overall, at least I don't think. But I think it's important people get the full picture with hybrid/electric/ev tech and take it all with a grain of salt.
 
Sure, it is. But I get the impression some people place a little too much faith in EV tech breakthroughs, we need a modicum of careful reality check. This group is smarter than most, I'd say.. but most people hear the word "electric" or "EV" or "hybrid" and automatically assume it's the magic pill to save the world. They see a Tesla drive by, watch the YouTube that spurred this thread, and think "gee, duh!" without getting the full picture of why we're not actually there.. yet.. and at this rate are still a very long ways off. A tiny two place electric plane that has no practical application is hardly a case-and-point of this technology's real world potential. The Airbus E-fan flew in 2014.. are we that much closer today than we were then?
Yes, we are closer. The Pipistral Alpha Electro is available. How do you define "practical application"?
I'd be happy if we had a plane with C172 or 182 performance and range, and charge it up within 30 minutes.


But in 3 decades those improvements are tiny, at least compared to 3 decades of improvements in virtually every other (generally much less well funded) field
Such as? Internal combustion engines are only seeing incremental improvements anymore. Same with aircraft.


..hopefully! it's a very real concern, from the article
"
Founded in late 2016, the company is part of a booming industry focused on preventing tens of thousands of tons of lithium-ion batteries from entering landfills. Of the 180,000 metric tons of Li-ion batteries available for recycling worldwide in 2019, just a little over half were recycled. As lithium-ion battery production soars, so does interest in recycling.
"
.. as it is now, that's a very depressing metric that nearly 90,000 tons of Li-ion batteries went to landfills... and I find that stat is unusually high, the stuff I've read puts that figure usually under 25% getting recycled, in this case just 5% https://grist.org/politics/most-lit...in-a-landfill-a-new-bill-aims-to-change-that/ BBC also quoted 5% https://www.bbc.com/news/business-56574779 Science direct has some peer reviewed journals on this as well. Most of these toxic landfills are out of sight, and hence, out of mind, and often in impoverished countries. Mind you, Tesla has cobalt in their batteries. The world's largest source of cobalt is the DRC (Democratic Republic of Congo), allegedly up to 40,000 children work in the cobalt mines. Mr Fancy-Pants Silicon Valley tech executive driving his Tesla might be individually adding less carbon to the atmosphere, but is his (or her's) general ecological and sociological impact to the world less severe?
I've read those papers, hence my question. People are aware of the waste from old batteries, and some of the recycling issues are because there are so many types of lithium ion batteries. Most people don't know, nor care, about where the things they use in daily life come from, nor their impact on the rest of the world. I suspect (my opinion) that's the cause of some of the politics now- people think (in some cases correctly, in other not correctly) that some environmental or social movement is going to change their lives, and they will be worse off for it. My opinion is also that some of those people look at the press announcements and see the comments by EV enthusiasts and think they will be forced to replace their pick-up with something far less capable for their needs. Those people have a stake in the effects of environmental decisions, too.

I'm not actually disagreeing with you overall, at least I don't think. But I think it's important people get the full picture with hybrid/electric/ev tech and take it all with a grain of salt.
For myself, I would be surprised to see electric planes carrying large numbers of passengers across the oceans within my lifetime, if ever. A small plane used by Harbour Air or Cape Air on short routes? I'd think that was possible, as is something within my piloting skills, which are modest at best.
 
The initial work on lithium batteries were in the 1970's

To reinforce that point. The initial work dates back to the early 1900's without having to squint your eyes too much. Earlier than that if you're willing to be a bit more hand wavey. But by 1912 the potential of lithium as an energy store was firmly understood and being worked on to replace nickel-cadmium batteries. It's just that it took almost hundred years to understand it well enough to only rarely cause emergency landings when the instability of the element itself causes problems.
 
Another (very) long term downside is that anything that it increases the surface friction of the planet, slowing its rotation ever so slightly. The same applies to wind and hydro - the energy does have to come from somewhere.

It comes from the sun. Wind and hydro don't change the rotational speed of the earth anymore than wind hitting the Rocky Mountains or water being captured in the 100 million plus natural lakes in the world do, or the 12,700,000,000,000,000kg of water in the clouds on a given day.
 
...Not to mention that lithium mining and battery development is not an environmentally neutral process. Burning fossil fuels, chemically speaking.. is fairly clean. Mining lithium, disposing of it, is remarkably toxic.

Okay but you don't burn fossil fuels until after you mine and process them and part of the disposal involves pumping the waste product into the air. I lived in LA in 1972 and remember how it looked, kind of like modern day Beijing looks now.

The recycling of batteries however is something that needs work. They are not being designed or manufactured with ease of recycling in mind and the cheaper the batteries get the less viable it is to make any profit off of recycling them. They need to do something like they do with mattresses, where you pay the recycling cost up front when you buy the thing.

Overall I think this discussion has been fairly well balanced. There are zealots at both ends but the reality is that it's not a slam-dunk either way. Using electricity for transportation has it's place, doesn't mean it's going to completely supplant everything else, at least not immediately. Fact is you still need to "make" the electricity to begin with and the advantage is that there are many different ways of doing that. The bottom line is we need to find something that is sustainable that we are not going to run out of in 100 or 1000 or 10,000+ years.

Buckminster Fuller said that fossil fuels are like the battery we are using to crank the engine and we need to get the engine running before the battery goes dead because it would take a few hundred million years to recharge it.
 
Ethanol in gasoline is supported by agricultural industries and no one else. The ethanol takes more energy to make than it gives up in fuel (fertilizer to grow, mechanisms to harvest, energy for fermentation, energy for distillation). We might be in a get ahead situation if we switched to microbial produced biodiesel, there are lots of algae that are up to 50% oil. Sadly biodiesel doesn't play well with our current distribution system, so it gets short shrift. But I promise you, if we're ever to have a renewable carbon based fuels it will come from microbes. Ethanol already does.
 
To reinforce that point. The initial work dates back to the early 1900's without having to squint your eyes too much. Earlier than that if you're willing to be a bit more hand wavey. But by 1912 the potential of lithium as an energy store was firmly understood and being worked on to replace nickel-cadmium batteries. It's just that it took almost hundred years to understand it well enough to only rarely cause emergency landings when the instability of the element itself causes problems.
Instability of the element? I don't think you mean that, as lithium is a fairly stable element. Perhaps you meant chemical reactivity of lithium metal (and the other group 1 metals)?
 
Okay but you don't burn fossil fuels until after you mine and process them and part of the disposal involves pumping the waste product into the air. I lived in LA in 1972 and remember how it looked, kind of like modern day Beijing looks now.

The recycling of batteries however is something that needs work. They are not being designed or manufactured with ease of recycling in mind and the cheaper the batteries get the less viable it is to make any profit off of recycling them. They need to do something like they do with mattresses, where you pay the recycling cost up front when you buy the thing.

Overall I think this discussion has been fairly well balanced. There are zealots at both ends but the reality is that it's not a slam-dunk either way. Using electricity for transportation has it's place, doesn't mean it's going to completely supplant everything else, at least not immediately. Fact is you still need to "make" the electricity to begin with and the advantage is that there are many different ways of doing that. The bottom line is we need to find something that is sustainable that we are not going to run out of in 100 or 1000 or 10,000+ years.

Buckminster Fuller said that fossil fuels are like the battery we are using to crank the engine and we need to get the engine running before the battery goes dead because it would take a few hundred million years to recharge it.
And the Chinese are recognizing that isn't good. Beijing wasn't as clear as the Jiangsu area when I was there last. I was a little surprised at that since I figured the leaders there would have insisted their air get cleared, first.

You've a good summary. Close the thread :)
 
It comes from the sun. Wind and hydro don't change the rotational speed of the earth anymore than wind hitting the Rocky Mountains or water being captured in the 100 million plus natural lakes in the world do, or the 12,700,000,000,000,000kg of water in the clouds on a given day.

Looks like I misremembered. But does tapping the tides still apply?
 
Surprised nobody brought up the topic most near and dear to an aircraft owner's heart. Maintenance.

The lack of preventative maintenance requirements was the biggest revelation to me when I got my Tesla M3. Somehow in all the hype and counter-hype, I never realized that the only scheduled maintenance for a Tesla is rotate the tires and inspect the brakes annually. No oil changes, no transmission fluid, no differential/transfer case fluid, no coolant, no hoses, no belts, no filters, no tune ups, no spark plugs, none of that.

That got me thinking about what an impossibly chaotic machine an ICE engine is. Thousands of small explosions a minute, harnessed by hundreds of whirling parts and gears constantly grinding against each other, bathed in various lubricants, generating noise, heat, electricity, smell, leaks, metal fragments, and some propulsion.

Nothing I love more than the roar of an aircraft engine, but once you compare that to the silence and simplicity of an EV, it gets harder to bet against that technology in the long run.

Of course Lithium batteries come with their own engineering challenges, but that is still a relatively young technology for widespread public use. Apply FAA airworthiness certification methodologies to EV production, and reliability may approach the point where engine failure is almost unheard of.
 
And fusion, at that! We use fusion now! And they said it would never work! :)
Yeah, we use fusion. In H-bombs. We can't control the rate like we can with fission. And I think there's a bit of a problem with confinement.

Nevertheless, modern nuclear power is a lot safer than it was 40 years ago. And human error was the biggest problem anyway, from careless or complacent operators to the people who decided to site a nuclear plant on a flood plain. Human error is usually the biggest problem in just about everything, including aviation.
 
The lack of preventative maintenance requirements was the biggest revelation to me when I got my Tesla M3. Somehow in all the hype and counter-hype, I never realized that the only scheduled maintenance for a Tesla is rotate the tires and inspect the brakes annually. No oil changes, no transmission fluid, no differential/transfer case fluid, no coolant, no hoses, no belts, no filters, no tune ups, no spark plugs, none of that.

That got me thinking about what an impossibly chaotic machine an ICE engine is. Thousands of small explosions a minute, harnessed by hundreds of whirling parts and gears constantly grinding against each other, bathed in various lubricants, generating noise, heat, electricity, smell, leaks, metal fragments, and some propulsion.

Nothing I love more than the roar of an aircraft engine, but once you compare that to the silence and simplicity of an EV, it gets harder to bet against that technology in the long run.

Yeah, but what do we tinker after we get a Tesla? We old guys are addicted to those noises and smells and filth and stuff. If I stick my head in the cab of an old truck, I'm young again. It smells like the old leaded gasoline of 1965, and the old motor oils and greases of that time too. Refineries do stuff differently now and none of it smells the same anymore.

Apply FAA airworthiness certification methodologies to EV production, and reliability may approach the point where engine failure is almost unheard of.

And affordability will be unheard of, too. Governments ruin everything they touch.
 
"
Founded in late 2016, the company is part of a booming industry focused on preventing tens of thousands of tons of lithium-ion batteries from entering landfills. Of the 180,000 metric tons of Li-ion batteries available for recycling worldwide in 2019, just a little over half were recycled. As lithium-ion battery production soars, so does interest in recycling.
"
.. as it is now, that's a very depressing metric that nearly 90,000 tons of Li-ion batteries went to landfills... and I find that stat is unusually high, the stuff I've read puts that figure usually under 25% getting recycled, in this case just 5% https://grist.org/politics/most-lit...in-a-landfill-a-new-bill-aims-to-change-that/ BBC also quoted 5% https://www.bbc.com/news/business-56574779 Science direct has some peer reviewed journals on this as well. Most of these toxic landfills are out of sight, and hence, out of mind, and often in impoverished countries. Mind you, Tesla has cobalt in their batteries. The world's largest source of cobalt is the DRC (Democratic Republic of Congo), allegedly up to 40,000 children work in the cobalt mines. Mr Fancy-Pants Silicon Valley tech executive driving his Tesla might be individually adding less carbon to the atmosphere, but is his (or her's) general ecological and sociological impact to the world less severe?

50% recycling rate? Plastic is under 10% and never bio-degrades, The plastic we through away will still be floating in the ocean in a thousand years.
That battery? it will have completely disintegrated. I think 50% battery recycling is actually pretty dam good compared to other attempts at recycling.

Tim
 
50% recycling rate? Plastic is under 10% and never bio-degrades, The plastic we through away will still be floating in the ocean in a thousand years.
That battery? it will have completely disintegrated. I think 50% battery recycling is actually pretty dam good compared to other attempts at recycling.

Tim
Do you trust the 50% though? The other articles and literature I found showed anywhere from 5% to 25%
 
I used your article. If you did not trust it, do not post it.

Tim
 
Do you trust the 50% though? The other articles and literature I found showed anywhere from 5% to 25%
The recycling rate will go up as more and larger batteries are used. It is hard to justify recycling a $0.25 battery in a toy or phone, but when you get $2000 per battery pack, there will be people lined up around the block willing to "take away for free" your old car battery pack for recycling. Once every car has a battery pack, they will (nearly) all get recycled.
 
The recycling rate will go up as more and larger batteries are used. It is hard to justify recycling a $0.25 battery in a toy or phone, but when you get $2000 per battery pack, there will be people lined up around the block willing to "take away for free" your old car battery pack for recycling. Once every car has a battery pack, they will (nearly) all get recycled.
Like laser printer toner cartridges. That makes sense.
 
Looks like I misremembered. But does tapping the tides still apply?

Tapping tides for power does not apply. But it is indeed tides that are causing the moon to recede and the earth to slow its rotation.
 
Baaahhhhhhhh, the earth is slowing, the earth is slowing!!!!!! LOL.
 
Oh boy, more hours in the day! I wonder how many millions of years we have to wait. :D
 
The answers here do seem to show any additional drag on the tides from tidal dams would slow the earth: https://physics.stackexchange.com/questions/6400/are-tidal-power-plants-slowing-down-earths-rotation

What is slowing the rotation of the earth is the interaction of the moon and the tides, as I previously wrote. Harvesting tidal power makes exactly zero difference.

Answer 1 in that thread basically says that even if there was a rotational cost, it wouldn't matter for millions of years, which is itself incorrect. The sun will be a red giant and consume the earth long before the earth slows to the same speed as the moons orbit regardless of tidal power. The moon is slowing the earth by 1.8 milliseconds per century.

Answer 2 in that thread is closer, but ignores that anywhere that we'd be building tidal plants is where the tidal energy would be knocking against the shore anyway. So the same energy will be transferred with or without the plant.

Answer 3 isn't even worth considering as it assumes a perfectly spherical frictionless world and gets the physics of even that simplified model wrong anyway.

I mean, really, the forces involved with creating tides are astronomical. If a real physicist could find an effect, it would be so many decimals down there as to be laughable.
 
Instability of the element? I don't think you mean that, as lithium is a fairly stable element. Perhaps you meant chemical reactivity of lithium metal (and the other group 1 metals)?

"Stable" is used in chemistry as well, not just physics. In chemistry it means relatively non-reactive. In physics it means, as you allude, that it isn't radioactive.

By a chemist's usage, lithium is wildly unstable. In physics it's stable.
 
"Stable" is used in chemistry as well, not just physics. In chemistry it means relatively non-reactive. In physics it means, as you allude, that it isn't radioactive.

By a chemist's usage, lithium is wildly unstable. In physics it's stable.
As an active chemist, I say lithium metal is reactive, and less reactive than sodium and the other group 1 metals. I tend to use "stable" in the context of molecules rather than elements, unless I'm talking radio chemistry.
 
Oh boy, more hours in the day! I wonder how many millions of years we have to wait. :D

It's a closely guarded secret, but by current measurements the days were only 22 hours long just a few years ago. It's why many old people get up at 5 am, and have to take naps in the afternoon. I worked with a guy who was so old that he said, as a kid, he'd get dizzy just because the earth spun so fast. That's why dinosaurs were so heavy...had to be, to keep from flying off.
 
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