YaDinghus

15 minutes ago, Cristiano said:

Supposing that I correctly calculate the integral to obtain the circumference and the area (I'm not sure right now), is there any numerical method that I can try?

That depends on how precise you need the results to be. As I've said, up to a ratio of 3:2 for the major to the minor semiaxis, the error is smaller than 1% for U = pi*(a+b). Since pi appears in both formulae for circumference and area, then A/U = ab/(a+b). This is the most I can offer right now...

12 minutes ago, dimreepr said:

My point is, "an eye for an eye" is a result of "primitive tribal revenge and escalating feuds of violence." not the cause.

All we can realistically expect from our current judicial system is justice (epic fail, but that's another topic).

Which do you think is fair:

A Rapist that gets to cross-examine/demean/traumatise the victim before, probably, getting acquitted.

or

 A Rapist that gets buggered senseless by a well-hung monster in public? 

I call chicken/egg on primitive tribal violence and eye for an eye.

As for your example with the rapist: I would love to see them get buggered by a well-hung volunteer in public, but that's my primitive instinct speaking. Since restitution isn't feasible in extreme cases such as this one, punishment is all that is left to exact

Of course I don't want to see a rape victim cross-examined in court and the whole affair dragged up in public. I'd rather see acceptance of a sworn statement from the victim and a specialist report from a medical professional who examined the vicitm. If that doesn't satisfy a jury, then the jury system needs to be revised...

17 minutes ago, dimreepr said:

I disagree and for these reasons:

The whole point is "an eye for an eye" not an eye for your sight, remember the context of the culture of its conception, more brutal and less educated, in which it becomes easily understood and, mostly, satisfactory. Does it work today? No, not generally but then how many are willing to forgive?

Ok what it looks like to me is that we are coming in from entirely different positions on the subject. For me, an eye for an eye can't be separated from primitive tribal revenge and escalating feuds of violence. Because that is exactly the context I know this principle from, while modern jurisdiction (ideally) focuses on reparation rather than punishment. You on the other hand are arguing from a point of strict mathematical logic where the exact damage is retributed to the purpetrayer of the original damage. It's not that I reject this outright, but it's also an idealized scenario, because either party will always view their own suffering as more significant than that of the counter party by any means possible. That's human psychology. Without a moderating instance the cycle of retribution will keep escalating, because humans are unable to be objective when their own suffering is involved

There is no straightforward method for calculating the circumference of an ellipse from the two semiaxes, so there is also no straightforward method for determining the length of any semi-axis from the area and the circumference.

Given the area and the suspected size of the major semiaxis, the small semiaxis would be 16839.3769767847. 

Wikipedia suggests that at this proportion of the major to the minor semiaxis the circumvmference U = pi*(a+b) yields an error of 1%. So for the current assumed configuration, U should be 136264.322253585, which is more than 1% outside the originally stated circumference

For clarity: close, but no cigar

1 hour ago, pavelcherepan said:

Australian winter, not a proper cold one, but then on the other hand, houses in Australia have absolutely garbage insulation.

A good insulation would also cut back on AC costs in the summer...

1 hour ago, studiot said:

Here is a plot (courtesy Lawden) of the Friedmann solutions to the Einstein Field equations showing the time evolution of universes with different input cosmological constant (k)

With negative k the universe expands without bound

With zero k the universe becoems asymptotic.

With positive k the universe expans and contracts cyclically.

 

So the real question is not

Is the uninverse infinite, but

Will the universe ever be infinite, and if so when?

 

you also have the lambda term in there that Einstein introduced to make the Universe static if k turned out to be different from 0, because he didn't like the idea of an expanding or shrinking universe. Now k is pretty certainly 0, with very small error bars, but it is expanding at an accelerated rate, so it's lambda we're looking at for dark energy and the continued and accelerating expansion of the universe. 

I've speculated in another thread that even at the Big Bang, the volume of the Universe might have been infinite, but that our observable universe originated from a single point of that big bang. Why shouldn't the isotropic principle extend to the Big Bang?

14 minutes ago, pavelcherepan said:

Depends on time of day of course. Between 4 degrees C and maybe 15 degrees on a good day.

You call that winter?

16 minutes ago, mistermack said:

It's hugely variable. The critical factors are not so much the temperatures, as firstly the quality of draught proofing, then the insulation. Only after that comes the type of heating and method. After all, if you don't lose any heat, you don't need any heat. You're only replacing what leaks away. 

Yeah... My parents got a new roof two years ago and that greatly reduced their gas consumption in the winter. Where they live it regularly goes below -10°C during the day and can reach -25°C at night. 

50 minutes ago, mistermack said:

Yes, about 155 pounds of air  !!

You know what, I missed the dimensionality of cubic meters. Thanks for catching that... So it's more like 200 W. That's a better ballpark, but it still seems low for winter heating. What's the outside temperature where you're at?

12 minutes ago, taeto said:

I think that I wrote it wrong to you, by missing that you said that isotropy is your assumption. Clearly the torus is anisotropic, just from the description of what happens if you observe different directions. My idea is better explained by suggesting that the Universe is flat and finite, but very large, so much that we cannot detect anisotropy by looking at the observable part. 

It seems quite reasonable to say that an absolutely flat and isotropic Universe has to be infinite. Interesting.

To be fair, we couldn't determine that just by looking out because we are looking back in time. To be sure, we would have to take a snapshot of what we see now and compare it with what we see over the next 14 bn years to see if other parts of the universe developed to be exactly what they are today. Also considering the accelerating expansion of the universe we might never be able to determine that because these regions would recede beyond our cosmic horizon by then...

2 hours ago, pavelcherepan said:

As MigL has correctly pointed, there is another way of looking at it. Is it likely that our understanding of space-time or electric fields will change significantly in time?

Since electromagnetism or GR are both theories, we are meant to update and change those if conflicting evidence shows up. Therefore, our understanding of what those phenomena are can, and most likely will change over time. New theories based on new observations can show it in completely different light. At the same time observable effects of space and time or electric fields, or electrons, will still stay the same. Therefore, I would consider those as 'real', but any theory or model can only be 'real' at one particular point in time.

I'd rather say our resolution of what any particle really is improves with the development of our theories. After all, any better theory won't simply replace but rather incorporate what we already know. After all it has to account for the observations we've already made

2 hours ago, iNow said:

Right now, in July 2018, when you google the word “IDIOT,” Donald Trump is the first result. Try it also on google images.

I’m not kidding. Try it. 

Confirmed. Though it says now that Trump said Einstein was an idiot...

1 hour ago, pavelcherepan said:

It is winter in Australia so heating and bills for it is on everyone's mind.

I was just trying to decide what method of keeping my house at reasonable temperature would be the best.

Suppose the total volume of heated premises is around 550 cubic meters, and if gas ducted heating is turned off, it cools down from 20 to 17 degrees in about 2 hours.

I could either turn heating on in short bursts getting the temperature up to around 22 degrees and then turning it off for a couple hours until it drops to 19-20. Otherwise, I could just keep heating constantly on at 19 or 20 degrees.

Which method is more efficient?

So you have a bit less than a pound of air in your house, which cools down from 293 to 290 K over 7200s, so basically you're heating with ca 200mW to keep it at 293K. I must be missing something...

1 hour ago, StringJunky said:

You clearly know more about the practicalities than I do. What about natural cotton type stuff, or fur even or hair. This is in France.

From my own csmping experience I do know that even in the coldest and dampest weather you can get anything dry enough for spark lighting if you've already got a fire going. Keeping it dry enough for prolonged periods I'm not sure, since processing leather requires some advanced technology and logistics, and roughhide isn't particularly good at insulating things from moisture. You could however carve out a wooden container to keep tinderlike stuff dry for a few days, and this should be able with mesolithic tools. The mesolithic period however begins well after the absorption of Neanderthals into the Sapien line (I am loathe to say extinction because of the significant levels of Neanderthal-specific genetic markers in Humans outside of Africa)

10 hours ago, taeto said:

      That does not follow. If the universe is a 3D torus, then you might be able to look in some direction and see yourself from the back, and if you look to your straight left, you might see the right side of your body. Or look straight up, and probably get dizzy. The same things repeat in all directions, and in total the universe has only finite content.

Obviously nobody knows if the Universe is a torus. If it isn't, my reasoning applies. If it is, that would be a limiting condition

9 hours ago, StringJunky said:

You could have a  universe within this one populated with particles that have weaker than neutrino-levels of interaction with this universe.

That kind of sounds like Star Trek's depiction of parallel universes which exist in the same space but have different 'quantum phases' so they don't interact with each other - or only gravitationally, which would explain dark matter, if we hadn't discovered galaxies that have a different ratio of light/dark matter, since a reasonable assumption would be that large scale evolution would be the same in gravitationally bound parallel universes

Quote

NASA's Hubble Space Telescope took an image of a bizarre, ghostly looking galaxy called NGC 1052-DF2 that astronomers calculate to have little to no dark matter. This is the first galaxy astronomers have discovered to be so lacking in dark matter, which is thought to comprise 85% of our universe's mass.

https://www.nasa.gov/feature/goddard/2018/dark-matter-goes-missing-in-oddball-galaxy

2 hours ago, dimreepr said:

Except an eye for an eye equals two lives not "too many lives", an eye for an eye is the simplest form of justice while a feud is the simplest form of revenge.

Ok what I forgot to weave into my argument is the tendency of humans to put their own suffering on a more sensitive scale than that of a stranger. So when three people ambush and kill your cousin who was involved in the murder of one of their relatives, you would go after all three of them to make them pay for their deed (with a few of your tribesmen for good measure). And so the violence spreads. It would have started because someone got killed while they were stealing cattle to which they were clearly entitled from their point of view, and so the killing even though objectively justified because he was defending his families property the thieves would consider it unjustified.

Now I am aware that I am mixing the concept of economic reciprocity with justice, but I do this to demonstrate how the eye for an eye justice system results in prolonged feuds cause more deaths than looking at the simple concept in question would produce.

2 hours ago, Sensei said:

Many not really bright politicians/jurists believe that way to prevent crimes is to increase years in jail.. They are seriously wrong..

regarding politicians I would say they are successfully pandering to their not really bright constituents. I'm not saying that this necessarily makes these politicians smart, but that stupid people will elect politicians who make bad laws. Also, in the USA, there are plenty of judges who are elected and not appointed, so they too pander to an electorate that wants harsh punishment instead of farsighted judgement

27 minutes ago, dimreepr said:

Firstly you have to understand the culture that that form of justice existed in, a small village/commune type culture which generally means everyone knows everyone, therefore the victim knows the assailant. In that circumstance, an eye for an eye is justice.

In a larger culture town/city it's easier for the assailant to avoid detection and if so (who does the victim extract justice from?) what choice does the victim have but to forgive?  

It's revenge, not justice, that blinds the world.

I get where you're coming from. But the context in the time of the formation of the jewish people already saw major cities and intertribal violence that was met out with blood over generations.

There have been tribal courts among the Nuër people of North Africa that would intervene when such a feud went on for too long and took too many lives. They formed a kind of trust to compensate the individual families (and the gods whom they asked for guidance) that the involved tribes would pay into so the feud could be ended. From this context it does make sense to say that while justice must be served, that the concept of an eye for an eye must be suspended when the original reason for the justice-seeking is no longer relevant, to cede it, or else the world would turn blind

5 minutes ago, Janus said:

3 lb/in³

Is it really per cubic inch? Pressure is usually per sqare inch... 

1 minute ago, Janus said:

At an equivalent pressure of 3000 ft, air is still quite breathable even for fairly strenuous activity, so for sitting in an aircraft it is quite sufficient, as it only lowers the partial pressure to 2.6 lb/in³.

Continental flights are that low? I didn't know... I usually only fly transatlantic, which is 30 k ft min...

2 minutes ago, StringJunky said:

In the 'death zone', above 25000-26000ft where it's 7%, a seasoned mountaineer won't last more than 48 hours there without supplementary oxygen. Basically, you are slowly dying over that period until you do die.

Thanks for that bit of Info 

11 minutes ago, dimreepr said:

I don't agree with this but that debate is for a different thread.

5 minutes ago, SamCogar said:

2 hours ago, YaDinghus said:

Have you been to college?

Yes I have.

I was awarded an AB Degree with a Major in the Biological Sciences and a Minor in the Physical Sciences, ….. @ GSC in 63'.

2 hours ago, YaDinghus said:

He properly cited research papers from established anthropology articles and books

2 hours ago, SamCogar said:

And you accepted that as a literal fact without questioning your instructor's wild accusations that he/she would have no knowledge whatsoever about the daily life of Neolithic hunter/gathers.   

Still shooting your own leg.

https://en.m.wikipedia.org/wiki/Original_affluent_society

Quote

At the time of the symposium new research by anthropologists, such as Richard B. Lee's work on the !Kung of southern Africa, was challenging popular notions that hunter-gatherer societies were always near the brink of starvation and continuously engaged in a struggle for survival. Sahlins gathered the data from these studies and used it to support a comprehensive argument that states that hunter-gatherers did not suffer from deprivation, but instead lived in a society in which "all the people's wants are easily satisfied."

I ain't got the time or the inclination to look for all the relevant sources my professor used back in the day, but the wikipedia article should give you an idea of the concept

4 minutes ago, dimreepr said:

I agree, but sometimes it's difficult to distinguish an excuse from a reason, especially when it's used to deflect criticism.

true dat...

5 minutes ago, Externet said:

Thanks.

OK, the air brought in by engines is of poor 7% oxygen content, plus the recirculated is also depleted of O2 by occupants;  so 7% is still enough oxygen at 30,000+ feet altitude  instead of 21% for passengers to not experience anoxia as for engines to combust ?

I have to assume the physical  inactivity of passengers is what makes a difference to alpinists in feeling effects in flights of many, many hours duration.

Does the ISS gets 'refills' from shuttles or is all the oxygen fully recycled ?

That doesn't sound entirely correct. For 7% O2 to be indistiguishable from 21% at sea level, cabin pressure would have to be 3 Atm. However, continental flights should be at an altitude where outside pressure is about 1/3 atm, while having the same oxygen concentration, it would be equivalent to the partial pressure of 7% Oxygen at sea level. You would not live for a very long time with that partial pressure of Oxygen, no matter your physical activity, unless you've just completed 2 months of intense altitude training.

10 hours ago, Janus said:

50% of the air is brought in from the outside and compressed, and 50% is recirculated cabin air.

Compressing the outside air however will equalize the O2 partial pressure, and jet engines reach compression levels far beyond what is needed for this task. In regards of fuel use for cabin air compression, it would amount to a rounding error

10 minutes ago, MigL said:

Just to be 'cheeky'...

That's Christians who believe in "turn the other cheek', Stringy.
Jews believe " an eye for an eye'.

That's a horrible play on words. I like it.

Anyway it was Lois Fisher, a descendant of Ukrainian jews, who said in his Book about Ghandi:

Quote

An eye for an eye will leave everyone blind

https://www.google.de/amp/s/quoteinvestigator.com/2010/12/27/eye-for-eye-blind/amp/

21 minutes ago, dimreepr said:

I don't think they see it that way, it seems they actively use that excuse to abuse others

And that's all it is, an excuse, and not a particularly good one at that. I'm certain you yourself have been hurt some time in the past. Do you use that as an excuse to go around and hurt other people? Would you accept this kind of excuse from someone else, or would you tell them that their shitty behavior is their own responsibility?

3 minutes ago, StringJunky said:

I think they do because their experience in the second world war, given that it happened over a relatively short time, intensifies and focuses the evils of fascist tendencies and the US, GB etc bent over backwards to carve out a piece of Palestine for them. They should be setting an example that is the opposite of what they went thorough in the 30's and war years.

I may have misinterpreted what you wrote but I'm open to being corrected.

What I mean in particular is that their history is somewhat of a red herring in this debate. Every people has atrocities in their past, commited by and/or agaisnt them, and should be fighting for a better, fairer, freer world.