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### Re: Science-based what-if questions

Posted: Wed Jul 12, 2017 12:04 am UTC
I was curious, I live on a river. Thank you.

### Re: Science-based what-if questions

Posted: Wed Jul 12, 2017 5:26 pm UTC
morriswalters wrote:So you want two back to back p traps connected by a portal and by implication the portal takes care of the energy involved due to the difference elevation assuming there is any. would that be correct?

Yes. Yes, it would.

Difference in elevation: from 9 to 1500 m ASL

9800 N * 1491 m = 1.46118 * 107 J per m3. Ouch.

Change in latitude: from 53.98 to 32.61°N

464.0846 m/s to 464.7603 m/s, 107.687 to 108.001 MJ / m3, a change of 3.41 * 103 J per m3.

To shift 200 m3/s that's 2.0007 GW of power requirement. I knew there'd be an energy cost but I hadn't realised Esfahan was higher above sea level than all of Britain. If the portal's not 100% efficient, that's 2 MW of heat, enough to boil 5l of water per second, for each 1% of that power that turns becomes additional heat, or enough to raise all 200000 litres by 2.4°C as it flows through. Those trout wouldn't survive a 0.15:1 heat:work ratio.

### Re: Science-based what-if questions

Posted: Wed Jul 12, 2017 6:33 pm UTC
Your heart is in the right place but physics says dump the water offshore of the outlet to the ocean. Floods are beasts however. The idea caught my attention because I see one every spring in the river I live next to. The river is large and navigable, so there is a dam and locks. The dam is somewhere over a mile in length and during floods the entire length acts in a manner consistent with how I see your portal working.

On a more humorous note, have you given consideration to the idea if you could do this efficiently on a small scale you could make sewer pipes obsolete, not to mention toilets as we experience them.

### Re: Science-based what-if questions

Posted: Thu Jul 13, 2017 2:29 pm UTC
morriswalters wrote:On a more humorous note, have you given consideration to the idea if you could do this efficiently on a small scale you could make sewer pipes obsolete, not to mention toilets as we experience them.
If you have access to portal gun technology, making sewers obsolete is setting the bar really, really low.

### Re: Science-based what-if questions

Posted: Sun Jul 16, 2017 3:52 pm UTC
Sableagle wrote:Change in latitude: from 53.98 to 32.61°N

464.0846 m/s to 464.7603 m/s, 107.687 to 108.001 MJ / m3, a change of 3.41 * 103 J per m3.
I don't know what exactly you calculate here, but the change in rotational velocity doesn't matter - it is taken into account by the sea level already which is an equipotential surface.

Portals seem to violate conservation of energy without problems, so we don't have to take care of energy.

### Re: Science-based what-if questions

Posted: Sun Jul 16, 2017 4:57 pm UTC
Sableagle wrote:
Change in latitude: from 53.98 to 32.61°N

464.0846 m/s to 464.7603 m/s
Those numbers are definitely not right, as they're both faster than a point on the equator.

It should be 272m/s to 390m/s.

mfb wrote:
Sableagle wrote:Change in latitude: from 53.98 to 32.61°N

464.0846 m/s to 464.7603 m/s, 107.687 to 108.001 MJ / m3, a change of 3.41 * 103 J per m3.
I don't know what exactly you calculate here, but the change in rotational velocity doesn't matter - it is taken into account by the sea level already which is an equipotential surface.
But this is also not right. Sea level is an equipotential surface, but taking velocity into account deals with kinetic energy, not potential.

### Re: Science-based what-if questions

Posted: Sun Jul 16, 2017 11:19 pm UTC
mfb wrote:
Sableagle wrote:Change in latitude: from 53.98 to 32.61°N

464.0846 m/s to 464.7603 m/s, 107.687 to 108.001 MJ / m3, a change of 3.41 * 103 J per m3.
I don't know what exactly you calculate here, but the change in rotational velocity doesn't matter - it is taken into account by the sea level already which is an equipotential surface.

Portals seem to violate conservation of energy without problems, so we don't have to take care of energy.
What you have to do is to conserve momentum. And thus the heat. Use magic to move water and mother momentum would demand her toll anyway. I'd like to tell you this was original thinking, but Larry Niven actually uses this as a plot device in The Ringworld Engineers. Which was why I asked.

### What happen when you remove Entropy?

Posted: Mon Jul 31, 2017 10:26 am UTC
In my current understanding, Entropy is the mathematically fundamental nature of all thing in the world,that, since it's make sure all possiblity are treated relatively equal (or rather the result of probabilty is the cause of entropy), is the reason why thing cool, people spread, and the universe's end. So what would happen if Entropy is suddenly remove from a system? I think since only Law is left, the law would then be exxagerate and the whole system would immediately shifted, from favoring the mass to favouring the few, the extreme, not only that but it would became unstable, shifting from one extreme to another.

Edit:...I also forgot that Entropy have like 30 different meaning now, so I just going to ask about the Physics one

### Re: What happen when you remove Entropy?

Posted: Mon Jul 31, 2017 12:04 pm UTC
andykhang wrote:In my current understanding, Entropy is the mathematically fundamental nature of all thing in the world,that, since it's make sure all possiblity are treated relatively equal (or rather the result of probabilty is the cause of entropy), is the reason why thing cool, people spread, and the universe's end. So what would happen if Entropy is suddenly remove from a system? I think since only Law is left, the law would then be exxagerate and the whole system would immediately shifted, from favoring the mass to favouring the few, the extreme, not only that but it would became unstable, shifting from one extreme to another.

Edit:...I also forgot that Entropy have like 30 different meaning now, so I just going to ask about the Physics one

Despite your edit I suspect you might still be conflating some philosophical concept of entropy with the physical concept. The real world doesn't work on some kind of law/chaos dichotomy and entropy is only very loosely correlated with what most people understand by chaos. I'll interpret your question as, "what if the second law of thermodynanics suddenly stops applying everywhere?". If that was not your question, could you elaborate a bit on what exactly you're hoping to find out?

Now I am not a physicist, but from what I understand of it the second law is essentially a mathematical theorem with some physical consequences rather than an experimentally verifiable physical theorem*, similar to how the fact that if I put one pen down on my desk and then put an other pen down next to it, there are now two pens on my desk follows from the fact that 1 + 1 = 2.

Hopefully, that analogy also illustrates how hard it will be to answer your question, you can't do what-if questions on logic. How would the world look like if 1 + 1 = 3 was true? If, when I put down one pen and then another and suddenly there are three pens without the third one coming from anywhere (not materializing out of nowhere, not poofing into existence by magic, but being there as a logical consequence of me putting down the 1 + 1 pens)? The question itself stops making sense as soon as you dive into it.

Suspending the second law, allowing closed systems to spontaneously become more ordered, may appear to be more plausible to us, but that is only because we understand the physics involved on a much less intuitive level (if we understand them at all). Fundamentally, your question makes as little sense as the 1 + 1 = 3 question.

*: I mean, the second lay is obviously experimentally verified, but in principle you could prove it without involving physics in any part after establishing the base concepts.

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 1:22 pm UTC
Oh yeah, logic basically evaporate when law isn't applied anymore is kinda anticlimatic though (not that I complain. Most scientific thing are anticlimatic)

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 1:47 pm UTC
Think of entropy as being the slope of time. The universe expands and entropy is linked to that expansion. If we started with everything that will exist at the singularity, then the density of the universe decreases by the rate of expansion. Every motion(and probably things I can't imagine) you see in the sky, orbits and so on, are a product of that expansion. Set the slope to zero and that expansion stops. The heat death of the universe.

I'm sure physicists are rising up out of their graves, but I believe it is close enough for government work. Dark xxxxxxx proponents are those people, who, when they do the math, realize that what they can see isn't enough to explain the observed rate of expansion.

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 2:20 pm UTC
Yeah, if your were like, "What if Mekop, the God of Order, resigned from the cosmos in disgust and his eternal rival, Ixos, God of Chaos, were left unchecked, what would the world look like?" then it would be a reasonable question. The answer would be a fun story. (Though the answer here is also a little unsatisfying, because, being the God of Chaos and Madness, Ixos will occasionally just bork over his own long term agenda for shits and giggles. Mostly he is very good but this tendency can be a bit unsettling for his allies.)

It is not that science is anticlimactic, it is that there are no good scientific answers to non-scientific questions.

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 3:05 pm UTC
doogly wrote:It is not that science is anticlimactic, it is that there are no good scientific answers to non-scientific questions.

<annoyingly precocious child's voice>Why?<annoyingly precocious child's voice>

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 3:47 pm UTC
That is not precocious, just regular type annoying.

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 6:09 pm UTC
Dammit, I always shoot this gun in the wrong direction.
doogly wrote:That is not precocious, just regular type annoying.
On the chance that's directed at me. It's probably true, since I have yet to find a way to correct defects in my knowledge without first laying my neck on the chopping block, and opening my mouth. So I understand that it is annoying. It what I have though and it's all I can do.

Having said that I don't see that it changes anything. If heat death is maximum entropy, what does the singularity represent? And why are we looking for elementary particles?

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 6:26 pm UTC
Oh no, it was directed at Soupsoon's description of the child who chants "whyyyyy" as precocious. I don't think that's quite what I would use that word for. There's special premature uncharacteristic or otherwise surprising cleverness or ability. Mostly just annoying.

Your statements above are generally legit and fine, not obnoxious.

I'm not sure what you mean by singularity. Like, big crunch end of the universe? Then we don't go into a heat death. That's a bit of a weird future but it also looks like we're not going there. It has a chance to bork with entropy though. In the heat death, things just equilibriate, the expansion doesn't stop. It just coasts. The entropy density can keep going down, forever. It'll happily asymptote.

What do you mean by 'why are we looking for elementary particles'? You mean, like, why do we bother? To get fed and laid.

### Re: Science-based what-if questions

Posted: Mon Jul 31, 2017 7:59 pm UTC
While they're getting fed and laid they're looking at the point t=0, 0 or perfect entropy, the top of the mountain. The point, which is as far as we can look backwards.
doogly wrote:Your statements above are generally legit and fine, not obnoxious.
I wish, my knowledge is defective. And I know it.
doogly wrote:The entropy density can keep going down, forever. It'll happily asymptote.
Yeah, I got it backward in school too.

### Re: Science-based what-if questions

Posted: Tue Aug 01, 2017 9:54 am UTC
The singularity is absolute minimum entropy; there's a single possible arrangement of things in a singularity. (Rather, our models fail at singularity, but at an ε afterwards, entropy is still exceedingly small and rapidly increasing.)

Heat death is maximal entropy; the *density* of entropy asymptotes toward zero, the total entropy asymptotes toward maximum for the given mass-energy.

### Re: Science-based what-if questions

Posted: Fri Aug 04, 2017 7:06 pm UTC
If we were to discover a single constant voltage source (for discussion purposes, it is in the form factor of a magical AA battery, eternally 1.5v difference between the ends), what would be the best uses we could put it to?

As an obvious starting point, I'd expect some superconductive, fractal wiring would be applied to spread that voltage out into a maximum amount of current. But simply reducing electric bills is far too mundane a thing to settle for.

### Re: Science-based what-if questions

Posted: Fri Aug 04, 2017 7:26 pm UTC
You have an infinite energy source. You could literally do pretty much anything with it.

### Re: Science-based what-if questions

Posted: Sat Aug 05, 2017 10:23 am UTC
So the best use would be to power a machine that sets an alarm 6 hours in the future and is triggered by that same alarm.

### Re: Science-based what-if questions

Posted: Sat Aug 05, 2017 5:09 pm UTC
SuicideJunkie wrote:If we were to discover a single constant voltage source (for discussion purposes, it is in the form factor of a magical AA battery, eternally 1.5v difference between the ends), what would be the best uses we could put it to?

As an obvious starting point, I'd expect some superconductive, fractal wiring would be applied to spread that voltage out into a maximum amount of current. But simply reducing electric bills is far too mundane a thing to settle for.

Anything you could do with a AA battery, forever. Do the math. (V=IR) They call it a power supply. What you seem to want is a power supply that specs P=infinity.

### Re: Science-based what-if questions

Posted: Sun Aug 06, 2017 8:49 am UTC
Could we run a "power-glider" drone with PTZ broad-spectrum cameras and long-range feed on one AA cell? Wildlife monitoring, refugee-spotting, wildfire-spotting, iceberg-spotting, glacier melt monitoring, ...

DC~AC converter, step-up transformer, mains power! Use it to power the tram network and ban all the cars.

### Re: Science-based what-if questions

Posted: Sun Aug 06, 2017 10:39 am UTC
Yeah, if it was literally an infinite AA, you'd be limited to things like the first option. If it's made of magic and has no current limitations, internal resistance, or operating temperature range, then there's a maximum current you'll be able to draw before it vaporizes whatever contacts you devise to connect it to your external system, but it's going to be quite a lot. What you do with that power is still likely to be pretty mundane.

Laser propulsion space ship?

### Re: Science-based what-if questions

Posted: Sun Aug 06, 2017 10:43 am UTC
Orbital sweeper. Stays in low earth orbit, grabs chunks of junk and throws them down into the atmosphere to burn up.

### Re: Science-based what-if questions

Posted: Sun Aug 06, 2017 11:54 am UTC
No, not very mundane at all. It allows situations where light bulbs have infinite current but zero resistance and can't give off light at all. It can be demonstrated by a current loop in a superconductor. Am I missing something?

### Re: Science-based what-if questions

Posted: Sun Aug 06, 2017 8:19 pm UTC
Well, I think only the power source itself is magical, not everything else we attach to it.

### Re: Science-based what-if questions

Posted: Sun Aug 06, 2017 10:49 pm UTC
Copper Bezel wrote:there's a maximum current you'll be able to draw before it vaporizes whatever contacts you devise to connect it to your external system, but it's going to be quite a lot.
I suppose using a plasma as a contact would work in that case, to turn the problem into an advantage.
It would then be a matter of tapping off the plasma tube for whatever you need and piping it around to convenient locations, and presumably feeding in some waste gasses to be recycled.

### Re: Science-based what-if questions

Posted: Sun Aug 06, 2017 11:10 pm UTC
Copper Bezel wrote:Well, I think only the power source itself is magical, not everything else we attach to it.
By definition it seems to break thermodynamics. But I concede that I might not be bringing my sense of humor along for the ride today.

### Re: Science-based what-if questions

Posted: Thu Aug 10, 2017 1:23 pm UTC
SuicideJunkie wrote:If we were to discover a single constant voltage source (for discussion purposes, it is in the form factor of a magical AA battery, eternally 1.5v difference between the ends), what would be the best uses we could put it to?

As an obvious starting point, I'd expect some superconductive, fractal wiring would be applied to spread that voltage out into a maximum amount of current. But simply reducing electric bills is far too mundane a thing to settle for.

Build an apple pie from scratch?

### Re: Science-based what-if questions

Posted: Fri Aug 11, 2017 4:07 am UTC
I have a rhetorical question, and anyone seriously interested in discussing the answer can PM me about it: Dr. James Gates Jr. discovered Error Correcting Code in String Theory. Why would there be error correcting code in the universe unless there are errors in the universe?

### Re: Science-based what-if questions

Posted: Fri Aug 11, 2017 5:25 am UTC
Eh, I'm not actually that excited by the discovery at this point. It seems fairly natural that if there's some kind of structure to the universe there needs to be something underpinning it that helps that structure stay what it is. It's probably like other phenomena where "the current laws of physics allow X, Y and Z but only X ever happens".

### Re: Science-based what-if questions

Posted: Fri Aug 11, 2017 8:38 am UTC
There is a pretty good answer on stackexhange. While the groups in question do arise in error correction, they also arise in many diverse areas of math. And they are not really out of place in string theory.

### Re: Science-based what-if questions

Posted: Fri Aug 11, 2017 4:10 pm UTC
Random question: if you form a black hole out of iron, is it subject to magnetic attraction? (Obviously, hard to test, I'm just curious if there's any operating theory on this.)

### Re: Science-based what-if questions

Posted: Fri Aug 11, 2017 6:35 pm UTC
commodorejohn wrote:Random question: if you form a black hole out of iron, is it subject to magnetic attraction? (Obviously, hard to test, I'm just curious if there's any operating theory on this.)

I think the no-hair theorem would say no.

### Re: Science-based what-if questions

Posted: Fri Aug 11, 2017 7:12 pm UTC
yeah, you could have it have a magnetic field, but not react ferromagnetically to some other field

### Re: Science-based what-if questions

Posted: Fri Aug 11, 2017 8:26 pm UTC
Even you make a black hole by shoving a bunch of iron together, you won't be left with a chunk of iron in the usual sense. You will have a black hole with a certain mass, charge, and angular momentum (and whatever magnetic field this results in). Where the black hole's mass-energy came from is largely irrelevant.

### Re: Science-based what-if questions

Posted: Sat Aug 12, 2017 4:22 pm UTC
I assume that a black hole originally made from iron may or may not have a magnetic field, but any field propagating away from the iron core would not pass the Schwarzschild radius. It is presumably undefined, and no experimental means would determine the original matter.

### Suneater

Posted: Sat Sep 02, 2017 7:18 am UTC
Supposedly I want to destroy a star. I wanted to do that by making a Kugelblitz - Black hole made out of light - By firing an array of intense (and i mean intense) light beam as a focal point inside the sun. A black hole inside a sun is obviously going to harm it, but at what size (and subsuquencely, mass) would harm it with a significant result on a short period of time? (Let said, in a month?)

### Re: Science-based what-if questions

Posted: Sat Sep 02, 2017 5:25 pm UTC
You can't use light to form a black hole in the center of a star unless the light can actually reach the center.