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Can Earth's rotation generate power? Physicists divided over controversial claim

nature.com

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Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#81

Post by aeternum »

MathMonkeyMan wrote: post #43
ziofill wrote: post #25

Wouldn't this eventually slow down Earth's rotation? The rotational kinetic energy of our planet is 1/5 M * R^2 * w^2 with (approximately) M = 6e34 kg, R = 6.3e6m, w = 7.4e-5 rad/s, which gives approximately 5e36 joules. Yearly we need roughly 3e16 Wh. Yeah ok there's plenty. Woah! (also, I may be off by some orders of magnitude)

This is addressed in the last paragraph of the article: > Even if it works, the method will not generate energy from thin air. It would tap Earth’s kinetic energy and, in doing so, cause the planet’s spinning to slow over time — although only slightly. If the technique provided all of Earth’s electricity needs, which was around 11 trillion watts in 2022, this would slow the planet’s spin by 7 milliseconds over the ne…

Isn't friction from the atmosphere already slowing the planet's spin? Many weather effects like hurricanes ultimately derive their energy from a combination of the earth's rotation and thermal/uneven heating effects so I don't see why this is contentions.

Like most things, nature is already doing it and has been for millions of years.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#82

Post by LegionMammal978 »

It would be interesting if this works. Last time people were hyping up a tiny effect with big ramifications that can only exist due to a subtle 'loophole', it was the EmDrive stuff that turned out to be driven by measurement errors. But I'm no expert in electrostatics.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#83

Post by Beijinger »

IshKebab wrote: post #65
npodbielski wrote: post #47

I wonder how many wats of power we would be able to generate before earth slows down for i.e. 1 second longer day.

That's easy to work out but I can tell you not it's going to be more than we will ever use.

You have no idea, what amount of energy we will be able to use the long run.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#84

Post by api »

LegionMammal978 wrote: post #82

It would be interesting if this works. Last time people were hyping up a tiny effect with big ramifications that can only exist due to a subtle 'loophole', it was the EmDrive stuff that turned out to be driven by measurement errors. But I'm no expert in electrostatics.

I was about 99.99999% sure that one was bogus because it was violating bedrock conservation laws. I'm not sure that this does. AFAIK there is no conservation law that says a spinning mass can't extract power from that.

Still... it would have been hilarious of the EmDrive had worked.

"Well, they've progressed! Last time we checked in on the third planet in this star system its inhabitants were still using warp drives to heat food. They appear to have realized this."

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#85

Post by [deleted] »

mr_mitm wrote: post #70
1970-01-01 wrote: post #67

A bad question, as it has been doing that literally (rotationally) since before life started. This power is busy generating the magnetosphere. We would not be enjoying our nice oxygen atmosphere and would be as dead as Mars if Earth's rotation wasn't also powering a dynamo.

It doesn't take any energy to maintain a static magnetic field though.

[deleted]

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#87

Post by Ylpertnodi »

grepfru_it wrote: post #63
EncomLab wrote: post #45

It's incredible the lengths humanity is willing to go to avoid adopting nuclear energy - despite the US navy driving mobile reactors millions of miles over the last 70 years.

Solve the waste problem and you solve nuclear. Waste is still the giant elephant in the room and a lot of people have a fifth grade solution to the problem (we will bury it under ground! We will fly it to the sun! We will resuse it until it is no longer radioactive!) I used to have a neighbor who worked for the DOE, all of the viable solutions are blocked by people who don’t want it in their backyard. Can’t really mo…

>Waste is still the giant elephant in the room and a lot of people have a fifth grade solution to the problem (we will bury it under ground! We will fly it to the sun! We will resuse it until it is no longer radioactive!)

Could the waste be 'sent' into space? Bonus points for sending a certain human with it. Serious question, though.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#88

Post by janpot »

IshKebab wrote: post #65
npodbielski wrote: post #47

I wonder how many wats of power we would be able to generate before earth slows down for i.e. 1 second longer day.

That's easy to work out but I can tell you not it's going to be more than we will ever use.

"640K ought to be enough for anybody"

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#89

Post by fallingknife »

pmontra wrote: post #54
EncomLab wrote: post #45

It's incredible the lengths humanity is willing to go to avoid adopting nuclear energy - despite the US navy driving mobile reactors millions of miles over the last 70 years.

Many countries would have to buy nuclear fuel from other countries much like they do for gas and oil. On the other side very few countries can build their own solar panels so it seems the same sort of problem. However if you accept to depend from potential hostile countries at least solar panels don't do much harm when they fail and it takes very little effort to install the equivalent amount of power of a nuclear po…

Unfortunately the arrangement of the continents would require undersea transmission lines for this. Would be an interesting future where the Bering Strait is the most valuable real estate on Earth for the American-Euraisian grid connection. But more likely we would build fusion reactors or get over our nuclear phobia before building something like that.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#90

Post by rsynnott »

Nifty3929 wrote: post #62
deepfriedchokes wrote: post #51

Earlier quoted context omitted.

The Navy isn’t constrained by economics. Nuclear doesn’t make sense economically compared to things like solar and batteries.

I haven't seen any data that backs that up based on general principals. Most of the cost is in artificially-imposed operational requirements - however well founded. Also, remember that nuclear, unlike solar, has a lot of room for improvement still, both in how it's done, and how it's regulated. Solar has already been tremendously optimized, while nuclear has not. The cost argument seems to be advances by the same peo…

> Most of the cost is in artificially-imposed operational requirements

Indeed. Once there was a wonderfully efficient, economical nuclear reactor design, better thermal efficiency than PWRs, could be refueled during operation, considerably cheaper to build… However, nobody is THAT keen to build more Chernobyls.

(The RBMK design really was quite impressive, provided you weren’t too concerned about, well, safety.)

The economics of nuclear energy are difficult, today. So much of the cost is upfront that getting the investment is problematic; unless you have a guaranteed price per kWh, it really is a huge gamble.

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