Are love tap bad for the car's structure?

Question: I am paranoid about my car being parked parallel in the street. If someone taps their bumper to my bumper , will it ruin the structure of the car? Will it mess with my alignment? How bad is it to receive a love tap? Don't know much about cars, so sorry about this stupid question.
Comment: Welcome to Motor Vehicle Maintenance & Repair! Not a stupid question by any means!
Answer: Not for the structure.
Industry regulations require that:

a car's safety systems must still function normally after a straight-on pendulum or moving-barrier impact of 4 km/h (2.5 mph) to the front and the rear

On modern cars, the bumper you see is a thin plastic cover. Underneath that cover is a large piece of foam or other absorbent/elastic material. Behind that foam is the actual metal structure of the vehicle. The foam looks like this, and it is this foam that occupies most of the space/shape in the bumper:

A low speed impact compresses the foam, then the foam springs back to its original shape thus retaining its ability to cushion the next impact.
While the structure and safety equipment of your car is meant to survive love taps unscathed, mechanical components and paint aren't designed to the same standard. For example, in an automatic transmission there is a pin that engages when the transmission is placed in Park. Bumping the car, especially repeatedly, can't be good for this pin and eventually the pin may break, requiring transmission repair or replacement [2]. If you are concerned with being love tapped, manually setting the parking brake can be a good idea [3]. And any sort of contact with the bumpers is likely to scratch/scuff them, even tear if the contact is with a license plate frame at an angle.
[2]:  For the pin to break the car would need to be tapped either many many times or be hit relatively hard. In any event setting the parking brake will likely extend the life of transmission.
[3]: One downside to setting the parking brake is the brake pads/shoes can get stuck to rotors after rain/snow, especially in winter. I usually do set the parking brake but I don't pull it all the way up as high as it will go.
Comment: Breaking of the parking pawl or pin does not always mean complete replacement of the transmission, but changing that part. Which does mean removing & refitting...
Comment: Just to confirm, if I'm going to parallel park, I should always set my parking brake to ON so that the pins won't break. In other words, I should always have my parking brake ON no matter where I park, just in case someone bumps me. Is that correct?
Comment: Amended the answer - there are pros and cons to setting the parking brake.
Answer: Structure wise you shouldn't worry about it. Bumpers are made to take a 5mph hit with zero damage (supposed to be here in the States, anyway). You'll see superficial damage to the paint and outer structures, though ... besides a scuff, a torn bumper cover may come of it.
Answer: In the good old days of parallel curb parking , more than a few people backed until they "touched" the car behind , then went forward until the touched the car in front . Everything was good unless there was broken glass from lights.


Why does church tradition teach that one third of the angels fell with Lucifer when no verse supports that

Question: The verse used is Rev. 12:4, but the context takes place in the midst of the great tribulation and not before Adam sinned.  Daniel 8:10 seems to confirm that the  stars that the dragon flung down were good angels, as he trampled them.  Those are the only 2 verses in the Bible dealing with this question that I can find and both infer that the 'stars' were enemies of the dragon not his fellow angels.
Is there something that I am missing here?
Answer: @BYE points in the right direction. Some of the prophecies in Revelation look backwards to events that occurred before John lived, because the contest between Satan and God goes back to the beginning of the world.

12 A great sign appeared in heaven: a woman clothed with the sun, with
  the moon under her feet and a crown of twelve stars on her head. 2 She
  was pregnant and cried out in pain as she was about to give birth. 3
  Then another sign appeared in heaven: an enormous red dragon with
  seven heads and ten horns and seven crowns on its heads. 4 Its tail
  swept a third of the stars out of the sky and flung them to the earth. (Revelation 12:1-4)

Verse four is interpreted by some to represent angels as stars. Thus the stars that fall to the earth are fallen angels, and they number one third of all stars, hence one third of all angels.

Jamieson-Fausset-Brown Bible Commentary

drew—Greek, present tense, "draweth," "drags down." His dragging down the stars with his tail (lashed back and forward in his fury)
  implies his persuading to apostatize, like himself, and to become
  earthy, those angels and also once eminent human teachers who had
  formerly been heavenly (compare Re 12:1; 1:20; Isa 14:12).

This commentary considers several possible meanings, including the stars being angels or martyred Christians.

Expositor's Greek Testament
Revelation 12:4. The symbolism is a
  reminiscence of an ætiological myth in astrology (cf. the cauda of the
  constellation Scorpio) and of the primitive view which regarded the
  dark cloud as a snake enfolding the luminaries of heaven in its
  hostile coils (Job 3:8; Job 26:13, with A. B. Davidson's notes). Thus
  the Iranians (S. B. E. iv. p. lxxiii., Darmesteter) described the
  fiend as a serpent or dragon not on the score of craftiness but
  "because the storm fiend envelops the goddess of light with the coils
  of the cloud as with a snake's fold". The same play of imagination
  would interpret eclipses and falling stars, and, when the pious were
  compared to stars (as in Egyptian theology, Plut. de Iside, 21), it
  was but a step to the idea of Daniel 8. (cf. Sib. Or. ver. 512 f., the
  battle of the stars), where Antiochus Epiphanes does violence to some
  devout Israelites who are characterised as stars flung rudely down to
  earth (i.e., martyred, 1 Maccabees 1.) Originally, this description of
  the dragon lashing his tail angrily and sweeping down a third of the
  stars probably referred to the seduction of angels from their heavenly
  rank (so 8–9) to serve his will (Weiss). But John, in recasting the
  tradition, may have thought of the Danielic application, i.e., of the
  devil succeeding in crushing by martyrdom a certain number of God's
  people. In this event, they would include at least, if they are not to
  be identified with, the pre-Christian martyrs of Judaism (cf. Hebrews
  11:32 f. Matthew 23:35).—ἕστηκεν, a conventional posture of the
  ancient dragon cf. e.g., Pliny, H. N. viii. 3, "nec flexu multiplici
  ut reliquae serpentes corpus impellit, sed celsus et erectus in medio
  incedens"; ibid. viii. 14, for serpents devouring children. The mother
  of Zoroaster had also a vision of wild beasts waiting to devour her
  child at its birth. This international myth of the divine child
  menaced at birth readily lent itself to moralisation, or afforded
  terms for historical applications, e.g., the abortive attack on Moses,
  the prototype of messiah (Baldensperger, 141, 142) at his birth (Acts
  7:20 f.) and the vain efforts of Herod against the messiah. The
  animosity of Pytho for Leto was due to a prophecy that the latter's
  son would vanquish him.

This commentary also agrees that the stars are angels:

Pulpit Commentary
Verse 4. - And his tail drew the third part of the stars of heaven, and did cast them to the earth; draweth (Revised
  Version). Not the stars with which the woman is crowned (see ver. 1),
  but other stars. In describing the vast power of the devil, St. John
  seems to allude to the tremendous result of his rebellious conduct in
  heaven, in effecting the fall of other angels with himself (Jude 1:6).
Comment: "*interpreted by some to represent angels as stars*", including by the Book of Revelation itself.  1:20 says "*… The seven stars are the angels …*", so it's hardly a stretch to think that other angles in the book also represent angels.
Answer: Your assertion that the emergence of the woman in 12:1 takes place during the tribulation does not appear to be correct, in light of these two verses taken together;

Revelation 1:19 KJV Write the things which thou hast seen, and the things which are, and the things which shall be hereafter;

According to this scripture, the Revelation is divided into three distinct sections. Those three are; the things you have seen, those that are, and those yet to come.

Revelation 11:19 KJV  And the temple of God was opened in heaven, and there was seen in his temple the ark of his testament: and there were lightnings, and voices, and thunderings, and an earthquake, and great hail.

notice that the command to write states have seen, which designates writing at a future date and not at the present; otherwise it would say what you see rather than have seen.
In verse 11:19 begins the opening of visions of the past. Verse 19 comes at the end of the seventh trumpet judgment.

Revelation 11:15 through 18 And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever.
  And the four and twenty elders, which sat before God on their seats, fell upon their faces, and worshipped God, Saying, We give thee thanks, O Lord God Almighty, which art, and wast, and art to come; because thou hast taken to thee thy great power, and hast reigned. And the nations were angry, and thy wrath is come, and the time of the dead, that they should be judged, and that thou shouldest give reward unto thy servants the prophets, and to the saints, and them that fear thy name, small and great; and shouldest destroy them which destroy the earth.

beginning with the vision: in 12:1 what we have is a summary of the charges against Satan and the fallen angels all of which took place prior to creation. We know this because;

Revelation 12:17  And the dragon was wroth with the woman, and went to make war with the remnant of her seed, which keep the commandments of God, and have the testimony of Jesus Christ.

These events are referred to in the past tense. notice and went to make war with her seed, and not will go. We have further evidence that these events are in the past due to:

Luke 10:18  And he said unto them, I beheld Satan as lightning fall from heaven.

These words of Jesus were uttered 2000 years ago and if it was past then it was surely past when John had his vision.
The Revelation is difficult to understand unless  we include the rest of the Bible in discerning what Jesus said.
Hope this helps.

Comment: BYE, you assert that "in 12:1 what we have is a summary of the charges against Satan and the fallen angels all of which took place prior to creation. We know this because the events are referred to in the past tense".  This doesn't make sense. It could not have been before creation, because before creation there was no woman, and the word had not even been used by God.  Adam and Eve were the first humans.
Answer: Yes, you are right to conclude that you must include the other books o the Bible, to discern what Jesus said.  We cannot actually see spirit creatures in their natural form, including Jesus and God. It is pretty evident that 1/3 of the stars mean the wicked angels that were kicked out of heaven.  The Bible warns of the things that would follow on the Earth after being kicked out of Heaven. From King James: Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time."  This of course is why things on the Earth are so bad!


Automotive Load Dump Protection Circuit

Question: Currently I'm working on a project that will be implemented in a 12V automotive electrical system. To protect the onboard DC/DC, I decided to add reverse polarity protection as well as load dump protection to the 12V+ input. After some research (and referencing this application note), I designed the following circuit (note: some component values were changed for BOM optimization):

Which produces the following simulation result (reverse polarity and over voltage (>30V) cutoff), as intended:

My main question is that in the TI AN they include an additional resistor from the drain of the n channel mosfet to the source of the p channel overvoltage mosfet (R4 in the below schematic).

What is the function of this resistor? The AN mentions its to bias Q2 and satisfy its drain leakage in the off state. Wouldn't R5 + R6 complete this function anyway?
Comment: Welcome. The sum of R5 and R6 is much greater than the value of R4.
Comment: What about TVS? I think it is custom(?) to place it directly after the polarity protection, so I suppose directly after D8 in your schematic. It should roughly be at 18V and you probably need the automotive spec >1500W ones.
Comment: Is it more commonplace to use an automotive TVS in this application? I'm aware of the high power units designed for load dump transients but I wasn't sure if they were the more desirable solution in this case.
Comment: Can you tell me which simulator you used?
Answer: Yes, (their) R5 & R6 can perform that function, but not as well, depending on your constraints.
To ensure the 2nd FET turns on well at low VBATT, you need to ensure that your R1 >> your R13; this ensures that at low VBATT, most of the supply voltage (VBATT*R1/(R1+R13)) appears across the VGS, turning the device on. However you can't make R13 too low, or at higher battery voltages, you will have too much current in the zener (Zener current = (VBATT-6.8)/R13) which could overheat it. You can't make R1 too high, or the turn off time will become too large.
Adding their R4 provides good turn-off time (approx. proportional to 1/(R4+R6)), but doesn't overpower the zener.
In fact, you could use R4 and eliminate R5 with no noticeable effect.
Be careful because not only are load dumps possible (and are relatively slow -- < 1 ms rise time), but other sharp high voltage transients can occur (e.g. double battery jump start @ 26.5 V, impulse noise). C1 also slows down the turn-off of the circuit at high input voltages (approx t= C.V/i = 100n*6.8/15mA = 40 us); 10 nF would be safer.
Answer: @jp314 has already answered exaustively to the second part of your question, thus I'll focust on the first part: and metodologically, I'll refer preferably to your schematics components labels, and only when in need I'll use the ones shown in the excerpt of the TI AN.

What is the function of this resistor?

Looking at the ZVN4106FTA datasheet (p. 3 of 6) you see that the \$I_{DSS}\$ can be as large as \$50\mu\mathrm{A}\$: this large leakage current implies that, whitout the \$R_4\$ resistor and when \$M_1\$ is OFF , you can have a gate-to-source voltage as high as
$$
V_{GS}\simeq -V_{R_1}=-R_1I_{DSS}\simeq -5\mathrm{V}.
$$
Having a look to the ZXMP6A13F datasheet (p. 4 of 8), you see that this voltage goes well beyond the maximum thresold voltage \$V_{GS_\mathrm{(th)}}\$ of the MOSFET (\$V_{GS_\mathrm{(th)_\max}}=-3V\$ as stated in the datasheet). Therefore, given the values of \$R_1\$ and \$R_{13}\$, the use of a pull-up resistor like \$R_4\$ connected on the drain of \$M_1\$ is absolutely needed since, apart from favourable statistical combinations (which may happen and usually do happen when you build your first prototype of the circuit ;) ) otherwise you may find that the \$U_1\$ MOSFET never goes OFF.
Finally, just for the sake of completesness:

The AN mentions its to bias Q2 and satisfy its drain leakage in the off state. Wouldn't R5 + R6 complete this function anyway?

Yes, you can choose \$R_5\$ and \$R_6\$ of suitably lower values, in order to obtain the same voltage division while avoiding excessive leakage dependent biases. For other problems related in doing so, see the answer of @jp314.
Answer: Check LTC4364 from Linear (now analog). It provides input voltage limiting, under-voltage and over-voltage protection, current limiting and over-current trip with delay depending on degree of overloading with recovery to your choice - automatic with cooling down delay or latched off (manual recovery or by re-application of power). It also provides two flags - one indicating protective intervention, the other controlling eventual downstream DC/DC converter. The chip requires external n channel MOSFET (or one more for reverse current protection if needed).

Automotive Load Dump Protection Circuit


How did Kakyoin get hit by The World when he was outside of its range?

Question: It is stated that The World has an effective range of 10 meters. It is a close-range stand, and we know that if any of the Joestar group entered this range of 10 meters, they would automatically be killed by The World with the power of the time stop. It's why Dio doesn't kill the group immediately when they reach his coffin, and it's also why Dio has to chase them. Even with The World's time stop ability, the group was not in range. However, Kakyoin was near the edge of a 20 meter Emerald Splash, yet he was killed. How did this happen?
Answer: The stand has a range of "approximately" ten meters, meaning that Kakyoin could've been just inside the Stands Range (unfortunately for him).
Dio probably knows by eye exactly how far away his enemies are from him and whether or not he'd be able to catch them in The World, so he walks forward until Kakyoin is just in range and then uses The World - otherwise he'd be wasting a perfectly good use.
I think also that Emerald Splash was 20 meters in diameter, not 20 meters straight forward, making it more likely that Dio would've been perfectly in range.
Comment: Kakyoin says 20 meter radius, so I'm not sure, but the approximation would make sense...
Answer:
(...) if any of the Joestar group entered this range of 10 meters, they would automatically be killed by The World with the power of the time stop. (...)

10 meters is The World's manifestation range. There is no need for a time stop.
Kakyoin knew this and only this, so he thought he would be somewhat safe if he was in 20 meters of DIO. What he didn't anticipate was for DIO to stop time, approach Kakyoin until he is in range of The World, then attack with The World.

Kakyoin learned the range of The World when he attacked DIO in his car earlier.
Answer: Range means attack range of the stand, not range of time stop. Time stop affects the whole world and is measured in time that Dio can act while everyone else cannot.
Answer: DIO'S The world was by technicality also far more powerful than Star Platinum: The World ever was, as he had practice, and was a vampire. I'm also pretty sure that his effective radius was growing at the same rate that his ability to stop time was after consuming Joseph's Blood.


Is the electromagnetic field strength tensor a tensor?

Question: The electromagnetic field strength tensor is given by:
$$\Bbb{F}^{\mu \nu}=\begin{pmatrix} 0 & E_x/c, & E_y/c & E_z /c \\ -E_x/c & 0 & B_z & -B_y \\ -E_y /c & -B_z & 0 & B_x \\ -E_z/c & B_y & -B_x &0 \end{pmatrix}$$
I know that this is a Lorentz tensor meaning (in accordance with the definition of such a tensor) that:
$$\Bbb{F}^{\mu \nu}=\Lambda^\mu _\alpha \Lambda^\nu_\beta \Bbb{F}^{\alpha \beta}$$
for a Lorentz transform $\Lambda$. But is it actually a fully fledged tensor, such that for any coordinate transformation we have:
$$\Bbb{F}^{\mu \nu}= \frac{\partial x'^\mu }{\partial x^\alpha} \frac{\partial x'^\mu}{\partial x^\beta }\Bbb{F}^{\alpha\beta}$$
Either way can it be easily proved and if not why do we call it the 'field strength tensor'?
Comment: @ocket8888 The standard definition of the term "tensor" in the context of differential geometry considers arbitrary coordinate transformations (diffeomorphisms).
Comment: Is that definition of coordinate transformations exhastive? Also, I thought the only coordinate transformations that mattered as far as the definition of a tensor was concerned were transformations to an inertial frame, is that not true?
Answer: Yes, it is.
First argument: Look at the Lorentz force law.
The electromagnetic field strength tensor is the one for which $$m\frac{d^2x^\mu}{d\tau^2}=q F^{\mu}_{\ \ \ \nu}\frac{d x^\nu}{d\tau}$$
so that $q F^{\mu}_{\ \ \ \nu}\frac{d x^\nu}{d\tau}$ must be a vector for all possible velocities you plug in. This tells you how the $\mu$ index transforms. We already know how $\frac{d}{d\tau}x^\nu$ transforms (it's also a vector), and so we can conclude how the lower $\nu$ index transforms.
This is nice and easy, because it relies on the fact that $\frac{d x^\nu}{d\tau}$ is a nice, geometric object - it is normalized tangent to a path in Minkowski space. It's a vector and it so it transforms as a vector. Likewise with $\frac{d^2 x^\mu}{d\tau^2}$. Those two transformation laws and the Lorentz force law force $F$ to transform like a tensor, period.
Second argument: It's defined that way.
I think the confusion here is that you have the mathematical formulation of the general coordinate invariance of tensors, but you don't have the physical formulation of electrodynamics in general coordinates. That would make the problem very difficult to think about!
Maxwell's equations are:
$$F^{\alpha\beta}_{\ \ \ \ \ \ ,\alpha} = \mu_{0} J^{\beta}$$
$$(\frac{1}{2}\epsilon^{\alpha\beta\gamma\delta}F_{\gamma\delta})_{,\alpha} = 0$$
where the subscript comma denotes differentiation with respect to that coordinate. i.e., $\phi_{,\alpha}=\frac{\partial}{\partial x^\alpha}\phi$. There is nothing going on here besides new notation - this is exactly what Maxwell did, and there is no difference!
Note also that $J^\beta$ is obviously a clear, true, physical vector. It points in the direction of real moving charges.
To work in general coordinates, even in flat spacetime, things get messy. There is a very sophisticated and difficult technique to dealing with the mess: Replace every comma "," (the derivative) with a semicolon ";" (the covariant derivative). OK, it's not that difficult. The semicolon hides all the extra terms which are added when you do a coordinate transformation. (What do I mean by this? The Laplacian of a scalar $\phi$ is equal to $\phi_{,\alpha\beta} g^{\alpha\beta}$, if $g$ is the three-dimensional (1,1,1) metric. If you do a coordinate transformation, the metric components change, and now the Laplacian is equal to $\phi_{\ ;\alpha\beta} g^{\alpha\beta}$. This hides all of the first derivative terms and what-not. Evidently THE Laplacian in arbitrary coordinates is $\phi_{\ ;\alpha\beta} g^{\alpha\beta}$, and $\phi_{,\alpha\beta} g^{\alpha\beta}$ is the Laplacian only in Cartesian coordinates.)
The theory of electrodynamics is now defined as the theory of a tensor field $F^{\mu \nu}$ together with the equations:
$$F^{\alpha\beta}_{\ \ \ \ \ \ ;\alpha} = \mu_{0} J^{\beta}$$
$$(\frac{1}{2}\epsilon^{\alpha\beta\gamma\delta}F_{\gamma\delta})_{;\alpha} = 0$$
This is now a true statement which is valid for all coordinate systems, even weird/bad/arbitrary ones: Cylindrical coordinates, spherical ones, parabolic coordinates, whatever you please!
There is no new physics in what I've said so far. This is just the differential geometry of weird coordinate systems, and Maxwell electrodynamics in weird coordinate systems. But the previous two equations hold just as well in curved spacetime, with no modifications, and that's nice.
Answer: It can be easily proved. But for almost every easy prove, there is some abstraction involved.
Luckily, I think I can offer some insight. Modern physics is very related to differential geometry and the main idea is that pure geometrical objects should have definitions which are independent of coordinates. Unfortunately, I don't have space and time to explain what is a proper geometrical object here, so the previous phrase will work as a definition.
That said, if you can define the $F_{\alpha \beta}$ without ever mentioning coordinates, you will know automatically that it is independent of which coordinates you choose.
The twist is that $F_{\alpha \beta}$ is not invariant as you pointed out, but
the quantity $F = F_{\alpha \beta} dx^{\alpha} \wedge dx^{\beta}$ is. So, if you could define $F$ before $F_{\alpha \beta}$, you would automatically know how this field strength tensor transforms from the requirement of $F$ being geometric. This is possible, but I cannot do it here. It is done, however, in every differential geometry book.
Let me explain a bit the notation.
$\bullet$ The quantity $F$ that I wrote is called 2-form;
$\bullet$ The symbol $\wedge$ is usually known as exterior product. It is there so that we can remember the antisymmetry:
$$ d x^{\alpha} \wedge d x^{\beta} = - d x^{\beta} \wedge d x^{\alpha}; $$
$\bullet$ The $dx^{\alpha}$ are known as basis $1$-forms. They are a basis for an abstract linear space usually known as cotangent space of a surface. This much you should not bother at the moment. The important thing is that you can sum and multiply them by scalars.
Under an arbitrary differentiable change of coordinates $x' \mapsto x$, the $1$-forms change to
$$ dx^{\alpha \, '} = \frac{\partial x^{\alpha \, '}}{\partial x^{\beta}} d x^{\beta}$$
and you can prove with the transformations you wrote (and I really leave this to you) that
$$ F'_{\mu \nu} (x') \, d x^{\mu \, '} \wedge d x^{\nu \, '} =
F_{\alpha \beta} (x)\, d x^{\alpha} \wedge d x^{\beta} .$$
Thus, $F$ looks the same under any change of coordinates. It is therefore
independent of which coordinates you choose and geometrical quantity.
Here, I reversed engineered the logic just so you can see how it works.
The direct way to prove what you want
is to define first $F$ and then work out $F_{\alpha \beta}$.
As a final comment, notice that two Maxwell's equations can be written in a manifestly invariant way under differentiable change of coordinates. They are known as Bianchi identities:
$$ \partial_{[\mu} F_{\nu \sigma]} = 0 \Leftrightarrow d F = 0. $$
The other two cannot be written in this way because they involve the metric, or more precisely, the Hodge dual. I should emphasize that diffeomorphic invariant things have geometrical significance and then you would know how their components transform. This is but one of many justifications of how it pays to have this level of abstraction involved.
Answer: Yes, because $F_{\mu\nu} \equiv \partial_\mu A_\nu - \partial_\nu A_\mu$. Hence, it is manifestly a rank-2 tensor since it is a sum of products of rank 1 tensors (vectors).
EDIT: This question is much more nuanced than I had originally thought. In order to actually show that it obeys general covariance, that is $F_{\mu\nu}$ is a tensor, we must generalize to Maxwell's equations in curved spacetime. That is to say, we must allow for accelerating frames of reference. Then, we know that $D_\nu F^{\mu\nu} = J^{\mu}$, where $D_\nu$ is the covariant derivative. Now, if $J^\mu$ is a vector, then it follows that the $\mu$ component of $F^{\mu\nu}$ also transforms like a vector (since we can pull coordinate transformations across $D_\nu$). By antisymmetry, this means that $F^{\mu\nu}$ transforms like a tensor.
Why must $J^\mu = (\rho, \mathbf{j})$ be a vector? To my understanding, this has to be argued on physical grounds, and is an assumption made outside the framework of Maxwell's equations. I could be wrong about this last statement, would appreciate an independent verification.
The moral of this story is that, yes the EM field strength should be a true tensor because we expect that, due to general relativity, the principle of general covariance should hold.
Comment: I updated the answer, sorry for my misunderstanding before


What are these brown spots on my tomatoes?

Question: Just formed today. I'm not sure what it could be.
Answer: The Missouri Botanical Garden has an informative publication on tomato fruit problems. The interesting observation in this case is that the spots all appear in the same rough location on the fruit. If it was a random attack by an insect or splattering by rain or irrigation leaving a local infection the spots would be in different places on the fruit. So there is some event happening like rubbing against a support; this might make sense on one or two fruits but here there are multiple fruits all showing the same thing. Another external event is the rising and setting of the sun which can in some cases lead to sunscald if there was a sudden change such as weather fluctuations or loss of foliage - you would be the best judge whether that is relevant. The document mentions look alike events such as stink bug damage and a bacterial infection but this would be in more random places on the fruit. So that leaves us with the most likely, sunscald. Over to you.


why variable have to be initialized?

Question: here i tried to get output month by inputting month number but why i am having error
 - "monthString" mightn't have been initialized ?
 - and why i am not getting output string  from " monthString "?
why monthString have to be initialized ?
import java.util.Scanner;
public class SwitchClass {

public static void main(String[]args)
{
   Scanner input = new Scanner(System.in);
   System.out.printf(" when did u born ? ");
   int monthNumber = input.nextInt();
   String monthString ;

switch (monthNumber)
{
    case 1:
    monthString = "January ";
        break;
    case 2:
        monthString = "February ";
        break;
    case 3:
        monthString = "March ";
        break;
    case 4:
        monthString = "April ";
        break;
    case  5:
        monthString = "May";
        break;
    case  6:
        monthString = "June";
        break;
    case  7:
        monthString = "July";
        break;
    case  8:
        monthString = "August";
        break;
    case  9:
        monthString = "September";
        break;
    case  10:
        monthString = "October";
        break;
    case  11:
        monthString = "November";
        break;
    case  12:
        monthString = "December";
        break;
   }
System.out.println(monthString);       }

 }

Answer: What if monthNumber is not between 1 and 12? In that case, monthString won't be initialized. You should give it some default value when you declare it :
String monthString = null; // or ""

Comment: Or create a default switch case, which gives it a value.
Answer: It would be a good idea to add a default case to your switch statement.
Example:
switch (monthNumber) {
    case 1: monthString = "January";
        break;

    //other cases...

    default: monthString = "Invalid Month Number";
        break;
}

This way if monthNumber is not 1-12 then there is still a default case for the switch statement to flow to.
Answer: monthString is a local variable within main(), therefore, it must be initialized to prevent the compiler error.
If monthString were a Class variable then it does not have to be initialized explicitly.
You can do this by moving monthString outside of main() and declare it as:
static String monthString;
Answer: Because the designer of Java language believes it made more sense for it to be! Codes are easier to read when variables are initialised. A statement String foo; feels non-deterministic because you have to guess what's the default value of String is whereas String foo = null; is more deterministic.
To give you a more obvious example, consider this:
int x;
Int y;

Can you very quickly guess what the default values are? You probably have to pause for a few second to realize x is probably 0 and y is probably null
Answer: Local variables MUST always be initialized before use.
For Java 6, the compiler doesn't consider the "Incomplete" initialization of variables within  flow control blocks and try-catch blocks. The initialization must be done for all cases:
If - else:
String s;
int a = 10;
if(a > 5){
 s = "5";
}else{
 System.out.println("");
}
System.out.println(s); // error if s isn't initialized within both if and else blocks

While loop:
String s;
int a = 10;
while(a > 0) {
  s= ">0";
  a--;
}
System.out.println(s);// error if s isn't initialized outside the while

Try-Catch block:
String s;
try {
 s = "";
    } catch (Exception e) {}
System.out.println(s);// error if s isn't initialized within both try and catch blocks

Switch block:
String s;
int a = 10;
switch (a) {
     case 10:
         s="10";
         break;
     default:
         break;
         }
System.out.println(s);// error if s isn't initialized all cases, default case included

Initialize the variable before the switch and all will be fine.
String monthString = "";

Comment: @ScottM. I think that my idea is clear now after improving my post.

why variable have to be initialized?


Any way to practice using the very tip of your pinky?

Question: I'm practicing a lot of scales as mentioned in my earlier question. When I stretch my pinky to reach for a distant fret, I almost always "land" on the side of my pinky. Is this ok? If not are there any specific exercises I can do to improve my technique, or will it just come with time?
Answer: I think this is something that will come with time, patience and perseverance, practising your scales.
You could however do something like the following to try and accelerate the process.  These exercises are just off the top of my head and not something I have ever used myself but they should help strengthen your pinky.  You can pick each note or try playing them as hammer-ons, and moving down the neck one fret at a time, at whatever speed you can comfortably play them.
<code>$6 1 5  $5 1 5  $4 1 5  $3 1 5  $2 1 5  $1 1 5
</code>
This next one should be done with your ring and pinky fingers or your middle and pinky fingers. whichever you use.
<code>$6 3 5  $5 3 5  $4 3 5  $3 3 5  $2 3 5  $1 3 5
</code>
These exercises are not very musical so I wouldnt spend too much time doing them, maybe make them part of your warm-up session and play them for 5-10 mins or so.
Comment: One thing I'd suggest is that you start these exercises in a higher position - perhaps 5-9 instead of 1-5 and 7-9 instead of 3-5. The stretch will be smaller and the the position of your left arm more relaxed, allowing you to concentrate on pinky precision. Once you're comfortable in this higher position, shift the exercises down a fret, repeat and continue doing this until you can play them in first position comfortably and accurately.


how to add the value of one column to the existing value of another column

Question: if i have a new comment in "new comment" column, i want that comment to be added to the existing comments in "comment summary" column but should be in a format of line break. How can I do this in Sharepoint Designer 2013?
Answer: There are two ways that you could do this.
You could solve this without workflow by turning versioning on your list and adding a multiple lines of text field with the appending setting turned on.  This will time stamp the comment along with marking who made it.  That is completely out of the box and works nicely, but may not fit your use case.
Another way to do this would be through a SPD workflow.  The pseudo code would look something like this:
<code>If 'New Comment' is not empty
  Set 'Comments Summary' to '[%Current Item:Comments Summary%]' + '[%Current Item:New Comment%]' //Format however you wish in the String Builder
  then Set 'New Comment' to blankString //Create local variable named blankString and don't give it a value
</code>
EDIT:
The first option's functionality doesn't work in quick edit and is also not able to be viewed in a regular list view (You will see 'More entries..' or something similar).  You can get around the viewing part by using a data view web part, but if you need to be able to quick edit then you will want to go with the workflow and second approach.
Comment: thank you jordan! i tried the first option and it worked, however, i cannot input a new comment if i am using the quick edit view. How can I enable inputting new comment via the quick edit?
Comment: Updated answer.
Comment: Thank jordan! I tried the 2nd option and its not working. Basically, I have 3 columns: 1st - for new comment, 2nd - will contain the new comment and modified details which is automatic, 3rd - is when I want to add the 2nd column to the existing details of 3rd column.

My string is:
If New Comment is not empty
   Set Comment Display to [New Comment],[Modified Date],[Modified by]
   then set New Comment to blankstring

If Comment Display is not empty
   Set Comment Summary to [Comment Summary] + [Comment Display]

Am I missing something?


The fluctuation-dissipation theorem

Question: In Giuliani & Vignale's Quantum Theory of the Electron Liquid, in page 126, they point out that the absorption and emission spectra are related by $$S_{AA^\dagger}(-\omega)=e^{-\beta\hbar\omega}S_{A^\dagger A}(\omega)$$ and that to obtain such relation, you should just start off from the definition $$S_{AA^\dagger}(\omega)=\sum_{nm}P_m|A_{mn}|^2\delta(\omega-\omega_{mn})$$
and take $\omega\rightarrow-\omega$ and interchange $n$ and $m$. I know that $\omega_{mn}=-\omega_{nm}$ and $\hat A$ is an hermitian operator.
But so far I haven't managed to understand how taking such considerations can lead one to the first relation. Any help would be welcome, thank you!
Answer: The averaging here is a thermal trace:
$$S_{AA^\dagger}(t)= Tr[e^{-\beta H}A(t)A^\dagger(0)].$$
You need to permute it in order to change the order of the operators.

The fluctuation-dissipation theorem


In Job 42 why was Elihu not equally rebuked?

Question: In the final chapters of Job, what happened to Elihu son of Barakel the Buzite, of the clan of Ram? In Job 42:7 God rebuked job's friends and ordered them to offer burnt offering to Job for misrepresenting him. Why was Elihu excluded? Was Elihu excluded because he gave an accurate representation of God?
Comment: That's more or less how I read it, but I remember learning that it has the appearance of a later splicing-in that wasn't fully integrated. I can't recall the details of this argument and would be interested to hear it again...
Answer: The reason that God did not rebuke Elihu is because he spoke the truth about Job's condition, unlike Job's three friends. Job's three friends accused Job of either doing something sinful or refraining from doing something that he should have done. Elihu, however, did not accuse Job of some kind of outward sin.
God had declared Job's actions as righteous. Elihu confronted Job with his inherent sinfulness (ie, his sin nature) and not with any specific external sinful behavior or action.  Elihu's rebuke was strictly based on the fact that Job was self righteous and he justified himself rather than justifying God. Look at chapter 32 and verses 1-2.
Job 32: 1-2 (KJV):

So these three men ceased to answer Job, because he was righteous in
  his own eyes. 2 Then was kindled the wrath of Elihu the son of
  Barachel the Buzite, of the kindred of Ram: against Job was his wrath
  kindled, because he justified himself rather than God.

Elihu's words:
Job 34: 5, 9 (KJV):

5 For Job hath said, I am righteous: and God hath taken away my
  judgment.
9 For he hath said, It profiteth a man nothing that he should delight
  himself with God.

Job 35: 1-2 (KJV):

Elihu spake moreover, and said,2 Thinkest thou this to be right, that
  thou saidst, My righteousness is more than God's?

Note Elihu's words are the same as God's:
Job 35:16 (KJV):

16 Therefore doth Job open his mouth in vain; he multiplieth words
  without knowledge.

Job 38:1-2 (KJV):

Then the LORD answered Job out of the whirlwind, and said, 2 Who is
  this that darkeneth counsel by words without knowledge?

Job and his three friends all believed the same bad theology. They all believed that you reap what you sow, where if something bad has happened to you, then you must have caused it through your sin. All four men believed this to be true; the only difference was that Job believed he didn't sin and his friends believed he did.  Again, the issue is not external actions but internal sin nature.
Elihu takes on the role of the prophet, justifying God where Job failed to do so. God's speech to Job starting in Chapter 38 is exactly in the same vain as Elihu's rebuke.
Answer: I disagree with the notion that Elihu, who is inserted to provide comic relief, was not rebuked because he "spoke right". Rather, he was not rebuked because he could do no serious harm (to Job) as:

he was "young" and inexperienced and so his words were discounted as they did not come from the lived experience of suffering, but from the enthusiastic intellectualizing of youth. Thus no one ever asked him for his opinion, no one debated with him, and no one (including God) responded to his long-winded and unsolicited speech. Everyone, including God, ignored him.

did not know Job well enough to make any personal accusations against him, and so spoke only of abstract principles.

Unlike the other characters, who came to Job out of concern for their friend and sat in silence with him for a few days, Elihu was an interloper who had a purely intellectual interest in the subsequent debate. His debate was only with himself, no one was interested in contending with him, and thus he gives his prepared speeches one after the other with no interaction.
That's not to say that readers should ignore Elihu's speech. The speeches of all the characters are of immense beauty and contain much wisdom.  But it seems pretty clear that Elihu was ignored by all, including God.
Comment: +1, I agreed. God has declared Job was righteous so Elihu was wrong to insult Job like that, but Job didn't take the offense because young man could make mistake.
Comment: why "comic relief?" I agree he was inserted - which explains why is not rebuked - but I agree with those commentators who see his speech as a kind of summary of the arguments of Job's other friends.
Comment: @DanFefferman In general in this genre, funnier/lighter things are said by younger characters and more serious things by older ones.  As a hint: the youngest man steps in to defend God's honor, and he does it by being angry at Job (his elder). He sputters, unable to contain himself, but he just overheard the conversation and is not the one who suffers or is even friends with Job. He replies but was not addressed. "My belly is as wine, I'm ready to burst like new bottles" - suggesting drunkenness/silliness. And it's hilariously long winded. He spends a chapter preparing them to hear his words.
Comment: @DanFefferman So it's this stereotype of a young person who is "full of words" and yet has never experienced anything, and is wading into matters that literally don't concern him except at an intellectual level. Again, that's not to say that the speech isn't inspired or filled with scriptural truths, but from the point of the narrative, it is presented as "less serious" than the speeches of those involved in the suffering (Job) or of his friends who went and sat with him, fasting in mourning for his troubles. Therefore it serves as a bit of a lighthearted interlude before the speech of God.
Comment: @Robert ... thanks much. I'll keep this in mind for further consideration. But for now I'll go with the view that Elihu's speech is a later addition, inserted by an editor who is unsatisfied with the earlier criticism of Job's complaint. If so that would explain why God doesn't deal with it. It simply was in the book when that part of it was written.
Answer: This question is already some years old, but I'd like to add something. The story gives us several clues why Elihu's speech should be taken seriously:

Whoever wrote down Elihu's speech, he gave this character the name Elihu, meaning 'He is my God'. As if the author wants to tell the reader that Elihu knows God in a personal way.
As @Carrie already mentioned, Elihu himself already admits he is younger. He held his tongue out of respect, hoping to gain wisdom from listening (32:6-7). But he got disappointed with the lack of wisdom of these older friends (32:11-15). That doesn't fit well with the picture that Elihu is just naive and inexperienced.
Job repeatedly interrupts his other friends but not Elihu. Not even when Elihu invites Job to respond (33:5, 33:32, 34:33). So it seems he accepts what Elihu says. Some argue that the others discounted Elihu's words and ignored him. Considering how they had been debating so far, this doesn't sound very likely (8:2, 11:2-3, 12:2-3, 15:2-6, and more). It makes more sense that Elihu hits the nail right on its head, and the others simply don't know what to say anymore.
In fact, the others have little chance to respond anyway, as God himself takes over Elihu's speech. Notice how smoothly Elihu's speech transitions into God's own speech (36:22-41). God continues exactly where Elihu stopped. So God does not at all ignore Elihu's speech, but even elaborates on it.
As OP noticed in his question, God rebukes Job's other friends but not Elihu. Some argue that God doesn't bother to rebuke Elihu and just ignores his speech. The point above counters that argument. Others argue that Elihu's speech was inserted later. Could be. But the most straightforward explanation is that Elihu said the right thing. Let's dive into that.

Job's friends talk mostly about God's blessings or punishments, whereas Job seems more concerned about God accepting or rejecting him. In Job's thinking, prosperity means God accepting him for being righteous, adversity means God rejecting him for being unrighteous. Job had seen much prosperity but now faces strong adversity. So given his thinking he wants an answer why God first accepted him and now rejects him (10:2-17, 13:22-25, 19:6-13, 23:3-17).
As his friends only think in terms of blessings and punishments, they don't understand what Job is really concerned about. In their thinking, prosperity means God blessing us for doing right, adversity means God punishing us for doing wrong. A very comfortable way of thinking. As long as you do right, you'll find prosperity. If someone is facing adversity, apparently he did wrong.
A righteous man facing adversity however would pose a threat to their thinking. Rather than reconsidering their thinking and comforting Job, they defend their thinking and attack Job with false accusations and vague speculations (8:4-7, and much more). If Job admits he did wrong, he would fit in their thinking again and be no threat anymore. Basically they sacrifice their friend to keep up their own comfortable way of thinking. But Job doesn't give in and the debate gets stuck.
Elihu does understand what Job is concerned about. First he takes the sting out of Job's thinking. He debunks the simplistic one-to-one relation between prosperity/adversity on the one hand and God accepting/rejecting him on the other. The adversity Job is facing does not mean God rejects him. God may also use this adversity to correct him (33:13-30). That must have been a big relief to Job, giving space for Elihu's next point.
@alb already sums up some of Elihu's key phrases. For me, the phrase from 34:9 especially stands out:

[Job says] there is no profit in trying to please God.

As far as I know Job didn't use those exact words, but reading back indeed it's pretty much what many of Job's words boil down to. So Elihu must have been listening quite carefully.
Yes, Job is perfect and upright. Yes, he fears God and turns away from evil (1:1, 1:8, 2:3). But referring to Job's own words Elihu points out that Job does so for his own sake. Job tries to please God for his own profit (34:9). That means Job's root motivation is selfish. Job's other friends could only throw false accusations and vague speculations. Elihu simply reflects Job's own words and pinpoints his underlying selfishness.
There's still lots more to find in Elihu's speech, about pride en humbleness for instance (35:2-16). Reading the book again with above in mind may open up new perspectives on the book as a whole and Elihu's speech in particular. And I'd like to add that it's easy to look at this story from a distant analytical viewpoint. But I believe this story is meant to reveal what's going on inside our own hearts as well...
Comment: I believe you're on the right track. I would add also that only Elihu was right on both of two important points; Job DID sin (from ch3 v1 onwards), which is why he has to repent in the last chapter. God commends him only after his repentance. But his suffering DID NOT come from his sin, and that is the mistake which the friends have to repent.
Comment: @StephenDisraeli Thanks for your feedback and I see your point. I have my thoughts about that too, as well as on many other treasures in the book. But I also figured that I should just stick with OP's question. So I set my scope strictly on Elihu and how he spoke well (in contrast to Job's other friends).
Answer: Job was perfect and upright.  He also didn't sin with his lips.  The reader needs to remember God is allowing Satan to punish Job, at Jobs request for he made burnt offerings on behalf of his children.
Now the sons on Job are trying to get past Satan, who argues their misdeeds before the Lord.  God says, in answer to Jobs prayers, why not look over here at this perfect Job...go beat him up.
Satan leaves the sons of Job on the threshold, and God gets Jobs less than perfect kids into the fold.
Elihu can be a young friend, he could be a personification of God.  Or, perhaps as some scholars argue...someone Other.
Elihu knows Satan has influence and power on the Earth.  In all this Job didn't sin.
Job is still perfect and upright even though he asked to pay for his children's sins, even though his three friends mock his perfectness, even though SATAN tortured him.  Elihu does not sin against Job.
People who write about job MUST consider that Job was Perfect and upright in the eyes of the lord and Satan.  Elihu isn't necessarily unrebuked, we just don't need to know how God deals with him.
Comment: Welcome to this site! You may note how Hermeneutics 'works' by taking the tour. Personal opinions are not sought but sourced material to substantiate any claim is helpful. We all have our views and interpretations, but these need to be backed up with references. For example, you could explain what the Hebrew word for 'perfect' means in context of this question. It does not mean that Job was without sin. Nor does the text actually say Job opened himself up for Satan's attacks by making burnt offerings to cover his childrens' sins. This is not to detract from your answer but to encourage you.
Answer: He was ignored by God because he was impudent in his condemnation of Job.  God said that Job spoke, "right."  Elihu just "piled on."
Comment: Welcome to Bible Hermeneutics SE and thank you for your contribution. When you get a chance, please take the [tour] to understand how the site works and [how it is different than others](https://hermeneutics.meta.stackexchange.com/questions/653/how-can-we-educate-new-users-about-our-site-distinctives/803#803).
Answer: Before addressing the question at the last point, here are other points to remember based on other comments:

Job may have been considered to be as righteous as a sinful man can possibly be, but he was by no means perfect. Every man born since Adam is sinful (Rom. 3:23) EXCEPT for Jesus (Heb. 9:11-14).
We have the benefit of scripture to understand what was happening to Job. Job did not.
We often can't discern God's purposes for events in our own lives or in the lives of our friends, but we are to remember He sees, knows, and is sovereign over all (Rom. 8:28, Eph. 1:11, Col. 1:16-17). His ways are higher than our ways (Is. 55:9).
We have the benefit of scripture to understand we face spiritual warfare (Eph. 6:12).
Elihu admits to being younger (Job 32:6). In a culture that actually respected elders, he held his tongue out of respect, hoping to gain wisdom from listening to them.
For him to have listened to them (Job 32:11-2), he had to have actually been there the whole time. He provides no comic relief. He is not an interloper. He is not spliced in at a later date.
Elihu is wordy. The first chapter of his speech is all about him asking the others to listen to him, again out of deference for the wisdom he expected their years to bring.
His words come because Job may be right about his innocence, but his emotions are self-righteous, not indignant on God's behalf (Job 32:2). He also saw that the three "friends" misrepresented God badly.
In our modern English Bibles (even KJV), there is much in the way of ancient Hebrew writing, speech, and culture that gets lost in translation. Some call parts of Elihu's speech pompous and arrogant, but they may simply have been common ways of making emphasis.
God's word is inspired and perfect (2 Tim. 3:16). God may not have chosen to honor Elihu in that moment, but He did choose to honor him by including his speech in the finished product of the Bible. God did not overlook him. Elihu defends God and His character, proclaiming His goodness, justice, and majesty. Maybe this is why he was not rebuked.
Answer: Reading this today, I see this ancient recorded exchange as a way to look at my own life today.... to wrap my head around things that have happened that I don't understand and that on some level feel like aren't the result of my own doing or choices. I read it as a call to examine the attitude of my heart and thoughts which then affect my words and actions. A reminder for me that God is huge and as it is said in ch. 34 :29..."Yet He is over individual and nation alike". He is also the God who sent His Son, full of grace and mercy. For us all...and for me as just me. Sometimes I forget when thinking about or talking to God who He is...and I approach Him on a level that needs rethinking. God help me to see You both as Mighty God and loving Father. And help me respond in humility and love and trust..remembering that promise in Romans 8:28...You will cause all things to work together together good for those who are called for Your purpose. You are a Father who takes care of Your kids.
Comment: And as for Elihu...I can't speak for why God did not reprimand him. I can only think that maybe it was because He can see his heart and motives. As he saw Job's and the other three men.
Comment: This does not provide an answer to the question. Once you have sufficient [reputation](https://hermeneutics.stackexchange.com/help/whats-reputation) you will be able to [comment on any post](https://hermeneutics.stackexchange.com/help/privileges/comment); instead, [provide answers that don't require clarification from the asker](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead). - [From Review](/review/late-answers/44201)
Comment: This answer is a very personal interpretation of the verse, but does not answer the OP question directly, so it's not the type of answer that is likely to be up-voted.
Answer: The reason God does not rebuke Elihu in the Book of Job is because Elihu's speech is a later addition to the book. The speech of God near the end of the book was not updated to account for Elihu's contribution.
The idea that Elihu's speech was inserted after the main body of the text was written is well established in scholarly literature.
In The Composition of the Elihu Speeches Helen Hawley Nichols stated that this view represents "the verdict of the majority of modern scholars."
More recently, Britannica affirmed:

scholars consider his section to be a later interpolation, perhaps by
a scribe who thought that the Book of Job's subject matter ventured
too close to blasphemy.

Not only is Elihu not rebuked by God; he also is not mentioned in Job 2:11, in which Job's friends are introduced. He bursts onto the scene out of nowhere to deliver his oration. Scholars have also pointed out that Elihu's speech is stylistically divergent from the other sections of the dialogue. However he does not actually provide a fresh viewpoint. Rather he offers a summation of Job's other critics' argument as if his is the superior opinion. God eventually affirms the correctness of Job's point of view and rejects the attitude of Job's "friends." But God is mysteriously silent about Elihu. The best explanation is not that God agrees with Elihu, for surely God would say so if the original text had included Elihu's speech.
The Book of Job is one of the great works of literature, as well as a very important book of the Bible. To understand it, we need to think about the editing process which resulted in the work that we have today. Recognizing that Elihu's speech was a later addition to the book clearly answers the question as to why God does not deal with Elihu in the final chapters. The reason is that God's speech was included prior to Elihu's speech, not because God endorsed what Elihu said.
Answer: Bro did you even read what's been written above? Elihu doesn't repeat the same arguments as the three friends. His argument is different, 32:2:
Job sought to justify himself instead of justifying God.
Stylistic differences alone don't guarantee a later addition. It's just a theory. The arguments put forth should be the emphasis.
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).
Answer: Modern scholars also believe the Hebrews crossed the REED sea and not the RED sea. They believe women can be called to preach, men can be with men, women can be with women, and some would say Christ never rose from the dead. I would rather believe what God said in the Book he preserved for us than try to argue away everything!
Comment: As it's currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer).
Answer: Can we not forget that God had a bet with the Devil. We should not overthink this.
No one is wrong.  Job was trying to understand what was happening to him. It was just normal for him to assess (not judge)  himself while trying to understand why things were happening to him.  He called on God and God didn't answer. God was waiting and He responded to him in the end.
The three friends on the other hand were simply applying a principle that is basic to the faith ie one reaps what one sows.  That is how our minds (in our faith) work.
It is just impossible for them to know what was really happening.  Hence God just gave them the simple penance of sacrificial burnt offering and a prayer from His good servant Job. Lesson learned: The principle of one reaps what one sows is for self assessment and not for judging others.  So don't judge.
And as for Elihu, he is just a young inexperienced person or a new believer who thought he knows and understands God. It's a big mistake but since he was young, God didn't bother.
Comment: @ Pong Policar - Thank you for your answer. However,  the first two paragraphs don't actually deal with the dilemma posed by the Question. Expand on the third paragraph, giving commentary research references if possible. Keep studying the Bible; it's great for the soul!
Answer: A lot of interesting answers to help understand this.  What I get from these dialogs including Elihu is we often can only guess as to how God is working in a life, even our own.  Elihu did not fall into the trap of blaming Job and saying he was suffering for his sin.  Nor did he fall into the trap that God was punishing Job for his sin.  He possibly sensed there was more to this situation than these friends could understand.  And the reader of the story already knows something these friends did not know, it was a test/trial God allowed.  It's likely Elihu was not mentioned because he did sense the bigger picture.
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).


Hosting company blocks remote access to database. How to deal?

Question: I used a shared windows hosting for one of my customers. The hosting company does not provide remote access to databases (e.g connecting through Microsoft Sql management studio). How do you work with such servers? Do you also set a web based database manager for every website? (or perhaps this special company is too restricted?)
Comment: Blocking direct remote database access is pretty common.   For Linux, most hosts allow you to ssh in and then access the database.  Maybe there is some equivalent access mechanism for Windows available from your host?
Comment: Plesk Onyx has firewall settings to allow remote access from specific IP addresses. I am not sure what your hosting provider is using but it might have equivalent settings.
Answer: Its difficult to give a good answer without knowing more specifics, but -
Remote access to databases is usually disabled because its a security risk with limited upside.  In the MySQL world it is common to provide access to PHPMyAdmin. I dont get involved with Windows much, but there are no doubt equivalent tools (eg https://sourceforge.net/projects/mammo/  - just from googling).
If you have a static IP address you may be able to request access directly from your hosting provider.  You might also be able to enable some kind of port forwarding (in the Linux world a tunnel over SSH)
It may even be possible (but mind you secure it) to use something like https://github.com/ngharo/Random-PHP-Classes/blob/master/Telnet.class.php to create a telnet proxy using php.


If I use an SSH tunnel to get around a firewall, what does the sysadmin see?

Question: I use an SSH tunnel for the port my browser uses to access the internet. The result is I get around the firewall my network uses, which prevents me from using many sites I want to use (facebook, anyone?). If I SSH tunnel like this, what does the sysadmin see about my internet history? Does he just see an SSH connected, and then encrypted information? Or can he see somehow I'm on facebook, and the SSH tunnel is only good enough for the firewall?
Answer: He will just see an SSH connection being open and perhaps some encrypted information when he does a closer data inspection. Unless he knows the encryption keys he won't be able to see what you're doing exactly. So from the network traffic, he will not be able to see if you've been on Facebook. Don't forget about browser history though. Your sysadmin might have installed something on every workstation to monitor browser history. I also doubt a sysadmin will go through so much effort just to prove you've been on Facebook. ;)
From http://en.wikipedia.org/wiki/Tunneling_protocol#Secure_Shell_tunneling:

SSH tunnels provide a means to bypass firewalls that prohibit certain Internet services — so long as a site allows outgoing connections. For example, an organization may prohibit a user from accessing Internet web pages (port 80) directly without passing through the organization's proxy filter (which provides the organization with a means of monitoring and controlling what the user sees through the web). But users may not wish to have their web traffic monitored or blocked by the organization's proxy filter. If users can connect to an external SSH server, they can create an SSH tunnel to forward a given port on their local machine to port 80 on a remote web server. To access the remote web server users would point their browser to http://localhost/.
Comment: hmm, i have a mac. do you know what software I should check for to see if they check my history? if i use stealth mode, will that address the history flaw?
Comment: @hatorade there's no way to know for sure. You should ask your sysadmin. Programs like these ***if they are installed anyway*** can be hard to detect. Private browsing or trying a different browser ***might*** work but there's no way to be sure unless you ask if and how you're being monitored.
Comment: true, but i figure someone here probably knows the more popular ones :)
Answer: Also, make sure to run DNS through your SSH tunnel. In firefox, this option is disabled by default. The network admin will only see encrypted traffic, as noted above.
about:config > network.proxy.socks_remote_dns;true
Comment: Hm. Can you point me to an option in Firefox which will set used DNS servers?
Comment: I updated my answer.
Answer: If you mean the internet history stored in your browser, that will still show the sites you visited. The SSH tunnel will only encrypt/hide the data as it moves through the network.
So you are hidden from network based detection, but not from them checking your computer. What browser are you using? Does it have a "stealth" mode ?
Answer: first question: is it YOUR computer you´re working with or is it the companys computer. if it´s the companys, you shouldn´t even think about using the ssh tunnel, because normaly the firewall blocks these sites in a company for a reason. If you neet to use i.e. facebook for work, talk to your admin.
But, the point of an ssh tunnel is to encrypt the traffic, so nobody can see what youre doing. So your admin only can see THAT an ssh connection is opened. Although, if he is able to view the browser history, he will see it.
But, as BloodPhilia said:

I also doubt a sysadmin will go through so much effort just to prove you've been on
  facebook. ;)


Can rainbow tables find the preimage of a hash?

Question: Given a hash value, how are you supposed to find its preimage? What steps can I take to solve find the preimage of a hash such as this 2d202cb6a781edf6ac01d14e1dd6367497db90ba9e8ad721fd17239228a213f9 (SHA256)
Answer: The only way to find the preimage of a hash value is to guess. There is no better way than trying all possible inputs by brute force until you find a match. This property is a design goal for cryptographic hash functions (preimage resistance).
A rainbow table doesn't help finding preimages, as such. Rather, it's a tool that helps you reuse somebody else's brute force work. If a rainbow table contains 1 trillion entries, then you can use it to find the preimage of any of those 1 trillion hash values in a short time. But the maker of this table had to make the 1 trillion hash computations. The reason rainbow tables are (occasionally) useful is that once the table has been built (a high one-time cost), you can make as many queries as you want (very low cost per query). It is useful if you have reason to believe that the preimage is among the 1 trillion in the table — if the preimage isn't one of these then all the rainbow table will tell you is that it definitely isn't one of these. See Crunge's answer on Security Stack Exchange for a very nice explanation of how rainbow tables work.
In practice looking up a hash value on Google is a low-effort way to find some simple preimages. When that doesn't work, it tends to suggests that tying to invert the hash won't be the easiest method of solving your problem.
Looking for the hash value in your question turns up a partial copy of a homework assignment which mentions "You should use the tools provided in the file, but are not limited to them." Said file was not included in that copy of the assignment, but it should be in yours. What you need to do to solve the assignment is, presumably, to figure out how the provided tools work.
Answer: Rainbow tables are not magic and will not help you find a preimage to an arbitrary SHA256 hashcode.
Unless you can significantly limit the space the original plain text was drawn from. For instance if the original text is a password from of limited entropy rainbow tables may be of assistance.
A simplistic intro:
Rainbow tables are a form of time-memory-tradeoff https://en.wikipedia.org/wiki/Time/memory/data_tradeoff_attack
Someone spends an effort on the order of brute forcing a single hash, but rather than make it a one time effort they store the results of their work. If they had enough memory to store all their hash invocations you could sort them by hash output and have a quick inverse lookup to invert any hash covered by the table.
However typically our compute capacity greatly out-ways our storage capacity(or transfer capacity). So we want to summarize the information. Time memory tradeoffs allow us to store less than a full lookup and still find pre-images for a large portion of the hash outputs. The more memory you have to store the faster (time) you can mount an attack against a given hash value.
More accurately we have a time-memory-data tradeoff, because a table doesn't provides full coverage of all possible hash values we can also adjust the likelyhood a given hash will be invertable with our setup, or conversely the number of attempts we have (how much data of hash outputs we have to try to invert at least one). The data trade off can be very significant when attacking stream ciphers.
If we want to invert one of $D$ hash values taken from a space of size $N$, we have enough storage to keep $M$ input&output pairs then for $D >> 1$ we get the following tradeoff. let $t=N/(M*D)$ the time to invert a single hash value with probability $1/D$ using a single rainbow table is $t^2/2$ .
If all you want is to use ready made rainbow tables take a look at http://project-rainbowcrack.com/ or https://crackstation.net/


Why oil traders selling oil on the day before expire date but not the other days earlier than that?

Question: As you know, the oil price was negative on April 20th 2020 due to the future contracts expiration date. I am wondering why traders had to wait until 1 day before expiration to close the position (sell or buy) or rollover but not some other days earlier?  they were waiting to make decisions or because trading at that time is easier to find sellers or buyers?
I'm a newcomer to the market. I really appreciate the help from all of you. Thank you in advance.
Comment: Sellers of options and futures contracts hold on for two reasons, price improvement due to decay and price improvement due to movement in the price of the underlying.  Knowing that one should have sold at an earlier date is a function of hindsight.  You can't know what the best date was to sell until expiration.
Comment: Ever hear the expression 'getting caught with your pants down'?
Answer: They weren't forced to sell on that particular day - in fact they could have sold the next day (on the day of expiry), or they could have sold the day before. But they were facing a ticking clock and as the market started to move down some were apparently willing to get rid of these contracts at any price. Those that had the guts to wait until the next day were able to sell them for up to $9, but no one know the day before whether the price would rebound or not. It's not necessarily easier to sell on any particular day.
Comment: Unfortunately some brokers did not support negative prices and did not let their clients get out when they wanted to. [One broker](https://www.businesswire.com/news/home/20200421005853/en/Interactive-Brokers-Issues-Statement-Crude-Oil-Contracts) said that due to the extremely negative closing price that day, many "incurred losses in excess of the equity in their accounts", and therefore they were not afforded an opportunity to get out above zero the next day. Their broker liquidated them at -37.63, because for all their broker knew, oil could have dropped to -200 the next day.
Answer: Traders of futures contracts, not taking delivery and not making delivery, should move to the next dated contract at least when that contract has more volume than the current contract.
And ETF's move to the next contract on a calendar schedule.
So who held on ?
A buy-side wouldn't be inclined to hold-on unless they could take delivery. The oil had more value than the value of the contract and so just take delivery. Well they might sell looking to re-buy delivery at a lower cost a few hours later.
A sell-side could be inclined to hold-on because of the extreme contango value even if not making delivery. But the sell-side has to eventually buy to get out if they are not making delivery.
It looks like the sell-side was making delivery and so not buying. And the buy-side was taking delivery but tried to get a cheaper contract by selling and re-buying.
It looks like an industry oil-trader panic and not a speculator panic. And the situation could have been a low volume pricing.
The buy-side might have bought more to average their price but oil storage was limited.
Oh, I didn't consider the crash to be a market-maker flash-crash because the traders still in the contract should have been those taking or making delivery. But the market-makers could have just left the market because the futures market is ultimately based on an accounting of delivery.
Comment: It turned out that day traders using leverage were buying at low prices thinking that zero was the point of maximum loss. But then when prices went negative the trading systems would not let the positions be closed out. Of course sell-to-close at near zero is downside pressure. Someone might sell two, for every one held, at near zero and gain from the downside.


Calculate Volume of Torus Given Circumferences

Question: What, if any, is the formula to calculate the volume of a torus given the circumference of the tube and the outer circumference of the ring?
Comment: The formula you're looking for is $2\pi^2 r^2 R$ where $r$ is the radius of of the tube, and R is the distance from the origin to the center of the tube.

The parameterization is given in the wikipedia article, and the integral is fairly easy to compute from that information.
Comment: https://en.wikipedia.org/wiki/Torus
Comment: http://mathworld.wolfram.com/PappussCentroidTheorem.html
Answer: By Pappus' centroid theorem, the volume of a torus generated by the rotation of a circle with radius $r$ with its centre on a circle with radius $R$ is just given by $2\pi^2 r^2 R$. In our case we have $\color{purple}{l}=2\pi r$ and $\color{green}{L}=2\pi(R+r)$, hence:
$$\boxed{ \color{red}{V} = \frac{1}{4\pi}\color{purple}{l}^2(\color{green}{L}-\color{purple}{l})}$$
Comment: Jack's answer is extremely clear and concise. I upvoted it. One thing perplexing is that the first formula for area not volume in the mathworld. So if one scroll down, one will find the formula for volume.
Answer: Since one can describe the volume of a torus using the radii of the two circles, the answer is yes. Suppose the circumference of the the larger ring is given by $C$ and the circumference of the smaller ring is given by $c$.
Similarily, let $R$ represent the center radius of the larger ring and $r$ represent the radius of the smaller ring. This is given by the picture

Thus the circumference is related to the radius by
$$C=2\pi (R+r)$$
$$c=2\pi r$$
Solving these for $R$ and $r$ yields
$$R=\frac{C-c}{2\pi}$$
$$r=\frac{c}{2\pi}$$
Using the formula for the volume of a torus $V=\pi r^2 \cdot 2 \pi R$ we obtain
$$V=\pi \left(\frac{c}{2\pi}\right)^2\cdot 2\pi \frac{C-c}{2\pi}=\frac{c^2(C-c)}{4\pi}.$$
This expresses the volume of a torus using the circumference.
Comment: I think maybe you want $V=\pi r^2\cdot 2\pi(R-r)$; see Jack D'Aurizio's answer.
Comment: Yup, my bad. I've edited the post accordingly.
Answer: There are already two answers here, but I went ahead and computed the volume using the parametric equation of the torus, given by
\begin{align}&x=(a+r\cos v)\cos u\\&y=(a+r\cos v)\sin u\\&z= r\sin v\end{align}
where $a$ is the distance from the origin to the center of the 'tube', $r$ is the radius of the 'tube' itself, and $u$ and $v$ are two parameters corresponding to the central angle and the circular angle inside the 'tube'.

The laboriously calculated Jacobian (giving the magnitude of the volume element at every point inside the torus) is simply $ar + r^2\cos v\,dr\,dv\,du$, so the volume of the torus is given by the integral
$$\int_0^{2\pi}\int_0^{2\pi}\int_0^r ar + r^2\cos v\,dr\,du\,dv=2\pi^2r^2R$$
as desired.
Edit: Since I'm doubly bored, I went ahead and found the volume using a solid of revolution method. The torus can be considered the solid constructed by rotating a circle around the $z$ axis. The volume is given by the double integral
$$2\pi\int_{-r}^r\int_{-\sqrt{r^2-x^2}+R}^{\sqrt{r^2-x^2}+R}y\ dy\,dx=2\pi^2 r^2 R$$
Technically, the variables should be reversed, but the answer is the same.
Comment: This answer would probably get upvoted if you (a) explained what the circmferences are in the problem, and (b) how your technique works. The parameterization also falls from the sky, so OP probably does not see how you actually solved the problem, just the answer.
Comment: Thanks for your comment. Updated with at least some exposition.


Transfering old photos in the cloud off my phone

Question: I linked my iPhone to my account in hopes of transferring the photos off of my phone to free up space. What happened was four years of photos transferred to my phone and it will not let me transfer the older ones off - what can I do to reverse this?
Answer: iCloud isn't for keeping photos permanently.
Bring them into iPhoto [Mac] or Photo Gallery [part of MS Essentials, Windows] for permanent storage.
After transfer you will get the choice to delete the copies on your phone.


Moon hit strong enough to put it in a slow spin?

Question: I'm building a world nearly equal to earth; i need a catastrophic event that make the moon start spinning breaking the tidal lock, a really slow spin, like 500 years for a full spin. i thought about a strong impact with great angle.
It will be possible while retain its orbit mostly unchanged?
Every scientific objection are welcomed
Comment: @DWKraus, black holes are stellar-mass objects, possibly heavier that the Sun, and one passing through the Solar System will wreak an immense havoc to planetary orbits. If you don't want Jupiter migrating inwards and ejecting the Earth out into interstellar space or flinging it into a deadly freezing orbit somewhere between Saturn and Uranus, better don't shoot black holes at our poor, barely dynamically stable Solar System! :)
Comment: Welcome to worldbuilding, please give a good read to our [help] to understand what we expect from questions here. You are asking more than one question, while we prefer only one, and I think some of them have already been answered here.
Comment: Sorry, i'll reformulate
Comment: Does it really need to be catastrophic? Maybe you could have other large celestial objects fly by and give it a slow spin. Repeat for a 500 year spin. A moon of Jupiter or something spins because of other moons if I recall correctly.
Comment: Well, it could in fact be something other than an impact, but i would settle for something spectacular, if not i could just assume that the moon of this planet isn't yet totally locked with the planet rotation. But if the forces in plays are the same, as the first answer, the gravitational force of the external body would break apart the moon before make it spin...
Comment: Is the goal to not have an extinction-level event occur on the adjoining planet from debris?
Comment: it would be great, yes
Comment: Welcome to worldbuilding, BTW. FYI I was able to direct a message specifically to you because this message box is under your posting. But to send a notice otherwise to someone so they know you mean for them to get it, you'd start the comment by putting their name with an "@" in front, so I would be "@DWKraus"
Comment: I don't know enough about the astrophysics of it, but a near-miss by a rogue black hole could certainly shift the rotation. I'm just not sure if it would also tear apart the moon or send the planet and/or moon out of orbit as well.
Comment: @DWKraus you're right! thx for the advice
Comment: I'm partial to a gigantic interstellar paintball splattering against the moon and painting a large portion of it black, and then the unequal weighting of solar pressure against the light and dark portions of the moon causing the moon's spin to change.
Comment: @JeremyFriesner I considered that! I just couldn't find a good way to justify it or muster faith it would work. :(
Comment: @kkm Well, it could go really fast, but there's a reason I didn't try to make it an answer...
Answer: The rotational kinetic energy of the moon is $3 \cdot 10^{23}$ J. In order to change the rotational speed of the moon, you will need to play with an energy of that order of magnitude.
The gravitational binding energy of the moon is instead $1 \cdot 10^{29}$ J, which is about 1 million times higher.
Therefore you can "safely" spin up the moon by grazing its surface with asteroid impacts.
Comment: @RBarryYoung thanks for finding the error, now corrected
Comment: I followed your link for "*Gravitational binding energy of the moon*", and it gives a different answer than you have posted.  You have it at 7*10^22 J, but that Wolfram page says that it is 1.244*10^29 J.  I suspect that you mistakenly read the moon's *mass*, 7*10^22 kg as the binding energy.  This would also resolve the mystery of how an intact body could have a higher rotational energy than its binding energy.
Comment: I was wrong as well, and energy in Alpha is for 27 days period of rotation, for moon - that 3.071e23, and for 500 years per rotation change the energy still 6700 times less than it is now, so a delta of energy is 44e18 J, which can be considered as standing still impactor with a mass of 100 million tons (difference of speeds about 30km/s)
Answer: The Moon rotates around the common Earth-Moon barycenter in a given time T1, and it also revolves around its own axis in a time T2.
Being tidally locked just means that T1 = T2.
And one solution to make it not tidally locked would be to vary T2. This would require to either brake or increase the Moon's rotation.
A different - actually, exactly opposite - approach would be to vary T1 by altering the Moon's orbit. This you can do by crashing a very large comet against the Moon, thus increasing (or decreasing) its orbital speed. The Moon's rotation would remain unchanged, and therefore would fall out of sync with the new duration of the Lunar month.
To decrease the effects of the impact on the Moon's integrity you might imagine the comet having recently broken up in, say, a close encounter with Jupiter. The impact would take place on a very large portion of the Moon's surface (a more catastrophic version of this impact is depicted in Jack DeVitt's Moonfall.
Even in a non-completely-catastrophic scenario (say, something like Bob Shaw's The Ceres Solution) you would get lots of ejecta, a considerable portion of which would certainly re-enter Earth's atmosphere, as well as very probably triggering a Kessler chain reaction.
A less catastrophic scenario would have the Moon narrowly missed by a much larger celestial body than a comet: large enough to "pull" the Moon outwards in its orbit. This would inevitably gravitationally influence the Earth and its orbit also, so most timebases would need to be recalibrated.
Answer: Volcanic eruptions can release enough energy to be comparable to the kinetic energy of the moon's motion.
Perhaps a glancing hit by a massive meteor could have ripped off the surface of this moon, and the intense tectonic response could spew enough lava into space to make the moon spin? The moon might have a glowing spot for a hundred or so years before it settled down.
Our moon isn't tectonically active, but yours could be.
Comment: A glancing blow could also mess with the gravitational bulb that takes form from gravity that is causing the tidal lock. If you hit that part, it could make the slowing down and it again being tidally locked take a long time.
Comment: Yep, that's what i was thinking about! it could be possible without destroying the moon, hurling it into deep space, or wiping clean earth surface with meteor shower?
Comment: Yep. Rather than a single push over a few minutes it would be numerous volcanic pushes over decades or centuries.
Comment: @Trioxidane, for calculations we model planets and moons as if they were made of a very viscous liquid, which they really are. Dispersing the "gravitational bulb," as you aptly called it, will do very little, as a new one will form immediately, on the scale of hours to days. Also, it's not a stable feature, and is shifting as the Moon librates due to its orbit's eccentricity, dissipating energy and slowing it down, causing it to lose orbital velocity and recede from the Earth.
Answer: A lunar day, equal to lunar orbital period, is ≈28 (Earth) days, adding a 1/500 yr^-1 to it corresponds to a relative change of (1/(500×365))/(1/28), which is about 150 ppm. Such a small deviation will likely be compensated by the orbital resonance attractor in the spin-orbit phase space, even given a low eccentricity of the Moon orbit. My feeling is that the Moon would return to the 1:1 resonance barely after 1-5 axial spins at the increased (or decreased) rotation rate. Since the Moon orbit eccentricity is very low (≈0.06), the resonant band of the spin-orbit phase space is quite narrow, and, as you likely know, separated from other resonant bands by chaotic bands. It is possible that the rotation speed will enter the a band of a chaotic regime, so that the rotation rate would not decrease smoothly back to where it were. The tidal heating will also vary then. In the final phase, the process shifts from the chaotic regime to librations of decreasing amplitude which may be protracted; surprisingly, this part is modeled by a dumped pendulum equations quite well.
The heat dissipated in the process could in principle start some volcanic activity on the Moon, and will certainly initiate outgassing in the heating rock, but I cannot speak to this, unfortunately. The excess energy, about 150 ppm relative, i.e. 1.5×10^-4 of the total rotational energy, is quite low. The largest unknown here is the time over which the energy dissipates. My feeling is the process should be quick, on the order of 10^2 to 10^3 years. Unfortunately, I'm not familiar with energy models when establishing an orbital resonance; I studied only the dynamics of it, where energy "just gets lost," so I have no intuition how much heating this will cause, and what the heating profile over time would be.
Sorry that this is a little bit handwavy. This is rather just my thoughts about how complicated the situation is, and that its outcome may be predictable or not, depending on how far off 1:1 resonance the system will be thrown, i.e. whether it will reach the chaotic band in the phase space. The Moon will not necessarily disintegrate from a glancing blow, as @l-dutch helpfully estimated. Such a blow will impart both spin and orbital velocity change, and the exact figure will depend on the angle of impact and the mass and speed of the impactor. A head-on impact will change orbital velocity without affecting spin, which will also disturb the resonance. Any impact, central or glancing, actually will. The impact itself will also produce significant amount of heat in an instant, which should also be accounted for. An off-equator blow will also send the rotation axis tumbling, which will eventually stabilize in the presence of Sun's gravity, that also should not be discounted. Planetary dynamics is already horribly complex even when these effects are ignored. I'd turn to numeric modeling rather than trying to write and solve equations accounting for all factors; they aren't likely even solvable (welcome to the wonderful underworld of the systems of PDEs!). But an impact that throws the Moon out of resonance by just 150 ppm is not catastrophic at all for the Earth-Moon system, and things will "get back to normal" almost instantly on the astronomic timescale, although the new "normal" may end up a bit different, due to a shifted rotation axis of the Moon and a different eccentricity and, albeit very slightly, radius of its orbit.
As a wild guess, does The Universe Sandbox has a model of tidal resonance?
Since you have a wide literary licence, you may assume any sensible regime in the range that I tried to describe, even if rather qualitative. If you want lunar volcanism, it's possible. If you want the impact ejeca reaching the Earth, it's also possible. A recovery time of hundreds to tens of thousand years is reasonable. Finally, if you want the Moon to end up rotating on a tilted axis with precession after the event, it's not only possible but very likely. If you do not, that's also does not violate physics, just requires a more or less precise nearly-equatorial momentum transfer, which is also realistic, given the relatively low energy gain.
Comment: wow, ok, this is really helpful! I guess i'm going to do some math, until i will eventually got bored!
Comment: @MicheleFornasari Unfortunately, the math here is so complicated that it's more common to resort to computer simulations. Or, rather, supercomputer simulation, if you want to account for heat distribution inside the Moon while it regains its resonance—this one is certainly unsolvable analytically. What we study analytically is a general structure of spin-orbit phase space, which is a simplified version of your question. It does not answer, for example, how much heat in energy losses is generated by each of the two bodies, only the total lost energy, or tells anything about the relaxation time.
Comment: @MicheleFornasari, I don't know how much background in math you have, but here's an introductory-level paper on types of orbital resonance and their phase space topologies. It's in fact even avoids PDEs, and is written in the ODE language, greatly simplified, but much easier to solve and feel the meaning of the equations. The exposition is well-paced and detailed: it's a seminar lecture, so you expect that attendees grok as you talk. Just in case, since you mentioned you wanted to do the math, it could be a good start: https://www.lpl.arizona.edu/~renu/malhotra_preprints/rio97.pdf
Comment: WoW, this is really interesting! I fear that it would be far off my math capabilities, but i will surely try it! Thank you


Skype is getting crashed even after removing the shared.xml

Question: I am also facing the same problem. It crashed even after removing the shared.xml. I tried all possible ways like re-start the machine, re-install the application etc. etc. But, nothing helped. If anyone got a permanent solution for this, please let me know.
Answer: http://skype.com/go/getskype-beta------this is the link to install the latest version from skype that will fix the crash issue that has been occurring for some time now---
If u read many ,many posts thru out this forum it has been advised by both skype users and skype moderators that this latest version of skype that was introduced on November 17th will fix the crashing issue many are experiencing--it is Skype Beta 5.7--and it works--just read the posts---thru out this forum--and also see the link I posted below--------see this link posted from Heartbeat------ -Go HeartBeat Skype
source; Skype


How do I get out of the rocks around the chest in the maze?

Question: I can get to where the chest is at the beginning, surrounded by rocks, but I can't get back out. I need capital W, I think. Could somebody tell me where to get it?
Answer: press capital "B"
so you  will jump to WORDS
Answer: I got stuck on this as well, you need to use the e key, but you don't have this at the start of the level, you need to continue along the island and jump across to the e key so you can use it.
Answer: You can use the e key while on the S square (lower right corner)

Forward to the end of word [count].
Position the cursor at the end of the word.
Does not stop in an empty line.
A word (see :help word) consists of a sequence of letters, digits and
  underscores, or a sequence of other non-blank characters, separated
  with white space (spaces, tabs, EOL). An empty line is also considered
  to be a word.


Can a Rigger command multiple drones when jumped into one?

Question: So a rigger with an RCC and a bunch of slaved drones jumps in to one of his drones. Can this rigger then use the send message/command multiple drones actions while jumped in?
Answer:
When you're jumped into a vehicle or other device, you're in Virtual
  Reality mode. (Core 266)

No rule mentions any restriction on Matrix actions as a result of jumping in. Commanding your drones is a Matrix action and you are present in the Matrix. It should pose no difficulty.
Answer: Shadowrun 5e CRB p267

Your RCC manages several parallel connections at once, so you can give a command to one, all, or someof your slaved drones with the same
Simple Action. This multi-connection also lets you jump from one
slaved drone to another without first jumping out of the drone you're
leaving.

Pretty straight forward. Note this relies on the pilot program and autosoft of the drone, you are not remote controlling them. Also jumping in is a complex action so you can't jump in + command drone in the same initiative pass. But by RAW it seems you can give a one phrase command as a free action:
Shadowrun 5e CRB p 164

SPEAK/TEXT/TRANSMIT PHRASE:
One short phrase of verbal communication is a Free Action.

Presumablly a drone's pilot program can understand a simple "shoot back" or "follow" command.
Comment: Jumping in is not necessarily a complex action.


How I Install Adobe Audition CS6 to Ubuntu 12.10

Question: How do I install Adobe Audition on Ubuntu?
Comment: See also: http://askubuntu.com/questions/228544/how-to-run-install-adobes-illustrator-cs6-and-photoshop-and-flash-and-indesign/228546#228546
Answer: @Hasiya Rulzz I have to bring to your notice that you might not be able to run any product from the Adobe Creative Suite 6 natively into linux. Even to do that you might need application like WINE and as J Moore pointed, you can see some serious issue's running Adobe Creative Suite 6 on Linux using WINE.
What I can suggest is, you have two options:

You can try installing a Virtual Machine for Windows and try installing Adobe Creative Suite 6 there to work on, that should not be an issue.
If you are not just specific to Adobe Creative Suite 6 and can install any alternative cross-platform audio editor then I would suggest you to try Audacity.

Hope this helps.
Answer: You don't; it appears to be broken in Wine: http://appdb.winehq.org/objectManager.php?sClass=version&iId=25911


How to display graphics in IOS when connected remotely with Linux server?

Question: I am trying to work using GRASS GIS for my data remotely from Mac. Here is what I have done:

XQuartz was installed and run;
Terminal was run. I typed: ssh -Y root@IPaddress
Then I typed: grass64 (to be able to use grass commands in terminal)
Afterwards got a question about directory to chose and the information:

WARNING: It appears that the X Windows system is not active.
A graphical based user interface is not supported.
Switching to text based interface mode.

I am struggling with enabling window to display rasters that I have. I tried to type -X despite -Y, as well running GRASS before, but nothing works.. My GRASS version is 7.8.
Any ideas?
Answer: Problem solved.
Tip for today: Always restart your computer before asking for help.